Paleozoic to Mesozoic sedimentary formations in the Colorado Front Range, Roxborough State Park: Documenting geologic landscapes and features through geo-photography
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Ellen Morris Bishop, Steve Weaver, Marli Bryant Miller, 2013. "Paleozoic to Mesozoic sedimentary formations in the Colorado Front Range, Roxborough State Park: Documenting geologic landscapes and features through geo-photography", Classic Concepts and New Directions: Exploring 125 Years of GSA Discoveries in the Rocky Mountain Region, Lon D. Abbott, Gregory S. Hancock
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Digital photography is an important tool to depict geologic features at all scales. Roxborough State Park offers an excellent laboratory to practice the skills and art of geo-photography. Three regionally significant Paleozoic through Early Cretaceous sedimentary formations (Fountain Formation, Lyons Formation, and Dakota Sandstone) offer important textural details, outcrop patterns, and structural relationships that provide photographic challenges and opportunities. In photographing these features, basic principles of composition apply, including the rule of thirds and the use of leading lines, foreground, and depth of field. To engage these, geo-photographers need to use important in-camera tools that include aperture, shutter speed and appropriate ISO (an adopted standard from the International Standardization Organization), as well as a tripod, and suitable lens focal length. Choice of file format (RAW or jpg) has important consequences for final image quality. Post-processing is essential to ensure that images accurately depict the features intended, and may include adjustment of levels, color temperature, and sharpening. GigaPan images offer an additional tool for examining geologic features at multiple scales using up to several hundred stitched images. Photographs are an important venue for communicating geologic information to both professionals and the general public, and the more the compelling the images, the more effective the communication will be.
Geo-photography is a photographic discipline focused on presenting geologic features, especially those of field geology, in a clear, attractive, and compelling manner. It includes many principles of landscape photography, but also requires the awareness of a documentary photographer or photojournalist, and borrows many macro-photography techniques.
Geology seems an easy thing to photograph—rock outcrops and landscapes usually don’t move very fast, and seem easy to snap pictures of. But for a geologic photograph to be successful, care in composition, lighting, focus, depth of field, and other technical factors, including post-processing, is essential to producing both an accurate portrayal of the subject, and a compelling image that will draw the attention of professionals and the general public alike. An excellent geo-photograph must “speak” to the viewer, communicating a sense of place, subject, and time. The most powerful images also evoke emotion. Digital photography allows geologists to shoot many images of their subject, experimenting with different compositions, and then, in postprocessing, fine-tune their picture to ensure that it depicts their subject clearly and accurately documents their work. This is a far different—and better—world than the days of shooting transparency film and hoping for the best.
Digital photography requires craftsmanship to ensure your photographs demonstrate their subject matter. You need not lug a DSLR and multiple lenses to far-flung field sites. Micro systems and high-level point and shoot cameras can now produce images that rival many bulky DSLRs, and also offer RAW image files and control over camera parameters including aperture and shutter speed.
A key factor in photography, as in anything else is practice. To shoot the best photographs of your field area, practice photographing other things and other places.
This field trip to Roxborough State Park (Fig. 1) will provide opportunities to practice the craft of geo-photography at scales from macro to landscape, including how to capture significant sedimentary features in the context of the geologic setting, and opportunities to depict the overall landscape and geologic history in compelling images.
Geology, Roxborough State Park
Roxborough State Park lies at the eastern foot of the Colorado Front Range ~35 miles southwest of Denver. The park occupies some 3,300 acres, and is designated as both a Colorado Natural Area and National Natural Landmark. Its chief geologic features include stark rock ridges, or hogbacks, predominantly of the late Pennsylvanian Fountain Formation, the Permian Lyons Formation, and the Early Cretaceous Dakota Sandstone. The park’s high point, Carpenter Peak (7280 ft) exposes Precambrian (Proterozoic) gneiss and two-mica granite that served as the roots of the Ancestral Rocky Mountains, and directly underlie the Fountain Formation.
The light-colored Early Cretaceous Dakota Sandstone represents shallow tidal zones and slightly deeper waters that record the transgression along the Western Interior Seaway. McKenzie (1972) reported a variety of shallow or tidal features including root casts, ripple marks, and dinosaur tracks from localities west of Denver. Schieber (2007) interpreted some rippled areas as algal mats, which also indicate shallow, tidal conditions and materosive ripple patches on a microbially bound sand surface. At Roxborough State Park, the Dakota Sandstone forms the (central) Dakota Hogback. Portions of a dinosaur trackway here have been identified as the footprints of ornithopod dinosaurs (hadrosaurs).
The Permian Lyons Formation comprises the central hogback in Roxborough State Park (Fig. 2). It consists of red-to cream-colored, fine, mature sediments, dominantly quartz arenite sandstone with interbedded siltstones and fine-grained microcline-rich arkoses. Calcite cement dominates. Sedimentary structures include cross-bedding, laminations ripple marks, and rare mud-cracks (Thompson, 1949). The Lyons Formation in Roxborough State Park displays some cross bedding, but also represents subaqueous deposits along the shore. In Jefferson County, just to the south, Weimer and Land (1972) interpreted the Lyons Formation as a fluvial deposit, based upon the presence of arkosic interbeds, mud-cracked shale beds and the scale and structure of ripple-marks which they interpreted as water-related. The 210-m-thick Lyons Formation extends from the Front Range near Colorado Springs to Wyoming, and is correlative with the more extensive Glorietta Sandstone in New Mexico, and the Coconino Sandstone of Arizona (Ross et al., 2010).
The Lyons Formation is generally considered to be the product of multiple, associated shoreline depositional environments, including dune, tidal or estuarine, littoral, and beach environments. The model of eolian or sabkha-dune deposit is applied throughout most of its exposures in the Colorado Front Range (Adams and Patton, 1972). However, in thin section, much of what has been reported as dunal sands are poorly sorted, even at Roxborough State Park, where the quartz content of the Lyons Formation averages 72% (Ross et al., 2010).
The Late Pennsylvanian (290-296 Ma) Fountain Formation forms the westernmost hogback in Roxborough State Park (Fig. 3). It is a red, generally arkosic, coarse-grained sandstone and conglomerate that represents a series of alluvial fans, fan deltas, and braided deltas along the eastern flank of the Ancestral Rocky Mountains (Maples and Suttner, 1990). With a maximum thickness of ~900 m (Sweet and Soreghan, 2008) its characteristic red rocks form distinctive hogback outcrops at the Flatirons west of Boulder as well as the Red Rocks near Morrison and the Garden of the Gods near Colorado Springs. Fountain Formation was weathered from the Precambrian granitic rocks of the Ancestral Rockies, and deposited under humid, tropical climatic conditions (Mack and Suttner, 1977) at ~5 degrees (N?) latitude (Sweet and Soreghan, 2008). However, the presence of polygonal cracking and fracture filling may indicate times of cold temperatures and significant diurnal temperature fluctuations, including repeated cooling under a strong diurnal cycle (10-25 °C day/night variation) and low ground temperatures (<0 °C), producing frost shattering and/or localized ice-segregation fracturing (Sweet and Soreghan, 2008).
Fossils are rare in the Fountain Formation. Invertebrates including bryozoans, brachiopods, crinoids, echinoids and gastropods have been found in limestone interbeds (Ellis, 1966), though none of these have been reported in Roxborough Park. Maples and Suttner (1990) argue that trace fossils that include Arenicolites carbonarius, Curvolithus manitouenis, and Macaronichnus segregatis indicate deposition of at least portions of the lower Fountain Formation in marine conditions, and propose deposition under conditions of marine-nonmarine cyclicity.
At Roxborough State Park, and elsewhere along the Front Range (Garden of the Gods, Red Rocks State Park) scenic hogbacks (cuestas) of Mesozoic and Paleozoic sedimentary rocks dip eastward at ~60 degrees. This uplift is the consequence of the Late Cretaceous to Paleogene Laramide orogeny. Folding and faulting was largely accomplished by thrust-faulting, which included displacements of 13-15 km eastward, and was driven by traction of near-horizontal subduction of the Kula plate (Bird, 1998). Motions, Bird notes, included the clockwise rotation of the Colorado Plateau between 75 and 50 Ma. Other models for the Laramide Orogeny include subduction of an oceanic plateau beneath North America (Henderson, et al., 1984) and the accretion of a Baja-California superterrane (Maxson and Tikoff, 1996). The Laramide was dominated by shortening due to horizontal compression, coincident in time with the Sevier thrust belt to the west (Erslev et al., 2004). Major thrust faults responsible for structures at Roxborough State Park include (east to west) the Rampart Range Thrust, Perry Park-Jamie Creek Thrust, and the 100-km-long Ute Pass-Cheyenne Mountain Thrust. Structural details within and near Roxborough State Park include well-preserved slickensided fractures in the quartz arenites of the Lyons, and Dakota sandstones, generally produced by back-thrusting motions.
Making Excellent Geo-Photographs In The Field
The well-made geo-photograph must clearly communicate the intended subject—geologic concepts and/or geologic features—to the viewer. In the best of worlds, there are three main requirements for making an excellent geo-photograph: (1) a visually interesting and well-defined subject, (2) effective techniques and equipment, and (3) good conditions, especially light. If you are aware of these requirements, you’ll be using your camera, which is simply a tool for collecting an image, to its best advantage. Photographs shot in optimum lighting conditions capture the viewers’ attention more fully and help you convey your visual message. It may be worth your time to return to a site late in the day or early in the morning to capture it in low-angle sunlight, which reveals subtle topography, or to re-shoot a scene when dramatic clouds provide a more memorable backdrop.
Photography uses both the left and right sides of the brain— the left for technical details, the right for creative vision. The creative aspects are critically important to making an excellent image. The geo-photographer needs to creatively pre-visualize the photograph, including which details are most important, then use technical knowledge to realize the image. For example, knowing how to make everything in the image sharply in focus, as well as how to emphasize the most significant geologic details using composition and light, can produce a more effective image than simply “pointing and shooting” (Fig. 4).
Tools For The Geo-Photographer
No self-respecting field geologist would venture into the wild without a hammer, Brunton (or an iPhone with the Brunton compass-like app, GeolCompass), and a notebook. There are a few tools that a geo-photographer needs as well.
Digital camera. The variety and price range of digital cameras are stupefying. For fieldwork, you want a camera that is light and a lens (or lenses) that can provide you with wide-angle, telephoto, and macro images. You should invest in a camera that shoots “RAW” files in addition to the more common jpg files. You can find excellent reviews and tests of cameras and lenses at www.DXOmark.com and www.dpreview.com. Here are some suggestions for a choice of camera.
A DSLR (digital single lens reflex) camera will provide you with the best image quality, provided you also invest in quality lenses. Camera manufacturers divide their product line into four tiers, in descending order: professional, prosumer, consumer, and entry-level. As one would expect, the components and image quality also degrade in that order. Top-level, or professional, DSLRs usually have a full-frame sensor (this is the same size a 35mm film), which include the Nikon D600 and D800, and Canon 6D and 5D Mark III. These cameras offer greater dynamic range and excellent image quality. Prosumer- and consumer-grade cameras often share the same smaller and less expensive APS-C-sized sensor—the differences between the two are mainly in camera features and build material. These cameras (Nikon 7100, Nikon 5200, Canon D60) are lighter-weight and can be fitted with sharp, lightweight lenses. The tradeoff is that their smaller sensors have less dynamic range and more image noise than a “full-frame” camera. However, in most cases, you will never notice the difference. Entry-level cameras (Nikon 3200, Canon Rebel series) have similar series designations as their consumer counterparts, but are far less endowed with features and are often poorly built.
Mirrorless interchangeable-lens camera (MILC) and micro 4/3 (MFT) systems have exploded in popularity within the past few years, because they are essentially DSLRs without the “R” (“reflex”) mirror, but a lot smaller and lighter. They have a wide variety of available lenses, and provide image quality equivalent to the APS-C DSLRs. Examples are the Panasonic GH- and GF-, Olympus PEN-, and Sony NEX-series cameras. These cameras offer a better alternative to entry-level DSLRs, as their build and image qualities are better with a lot more camera features and controls.
High-quality compact “point-and-shoot” cameras: Many professional photographers do not want to lug a lot of heavy equipment around, and need a light, easy-to-carry “backup” camera. Thus, the large-sensor compact camera was born. These cameras have a DSLR-quality sensor built into a compact body that often looks like the less-capable “point and shoot” cameras. Some high-quality compact cameras have zoom lenses, others a single fixed-focal length (usually, a 50mm or 28mm equivalent). Older versions include the Canon S95 and S100; newer models include the Fuji FX100 and Nikon Coolpix A. Prices are equivalent to what you might spend on an economical DSLR outfit— camera and lenses—but you won’t have to lug a lot of stuff to get excellent images.
Smart Phone: Many phones now include a digital camera that captures surprisingly high-quality images, despite their Thumbelina-scale sensors. Some smart phone cameras produce images that rival or exceed inexpensive point and shoot cameras. While smart phones (currently) lack the capacity to adjust apertures and otherwise behave as conventional cameras, they are accessible and eminently portable. Since “the best camera is the one you have with you” (Jarvis, 2009) a phone chosen specifically for its photographic capabilities (Nokia 808; Samsung Galaxy S4 and above, iPhone 4s, and above) may be included in your photographic arsenal— although their image quality will leave much to be desired compared to cameras discussed above.
While weight is one important consideration in choosing a camera, the inherent image quality is another. Although the quality of light and technical skills of the photographer are critical in producing a quality image, the camera itself is important (as is the quality of any tool.) The camera’s image quality is determined by (1) the technology built into the camera’s sensor and processor, (2) the quality of the lens, and (3) the camera sensor’s size. Full-frame DSLRs, including the Nikon D800 and Canon 5D Mark III, have large sensors. So, individual pixels on a full-frame 24 MP (megapixel) sensor are larger and hence can resolve more detail than a 24 MP sensor on a APS-C DSLR such as the Nikon D5200 or Canon D60, or even the smaller sensors of compact cameras and phone-cameras (which are tiny). The only advantage of a small sensor is its ability to provide greater depth of field—i.e., how much of the image, front to back, is in focus. A small-sensor camera will provide greater depth of field at any given aperture than an APS-C or full-frame DSLR.
Lenses. It is important to note that all focal lengths discussed here are standardized to “full-frame” equivalents. Smaller-ensor cameras have a fi eld of view crop factor (FOVCF) or focal length multiplier (FLM) associated with that particular sensor size. APS-C sensors usually have a FOVCF of 1.5× (Nikon) or 1.6× (Canon), while most MFT systems have a FOVCF of 2×. For example, a 100mm lens on an APS-C camera will have the same f eld of view as a 150mm or 160mm lens on a full frame Nikon or Canon DSLR, respectively. Compact cameras have a lot more varied sensor sizes, but the equivalent 35mm focal lengths are usually listed in the camera’s specifi cations. Lenses that have a single fi xed focal length are called “primes,” and variable focal length lenses are called “zooms.” In general, prime lenses are sharper and lighter than zoom lenses; although, modern zoom lenses have come a long way. Some zoom lenses that rival primes in sharpness and weight will usually cost at least twice as much.
Focal lengths are generally divided into three categories: wide-angle, standard, and telephoto. A 50mm lens is considered the standard lens (mainly because most cameras in the days of film came with a 50mm or 55mm lens in a standard kit), which is a good general purpose lens. This focal length is often referred to as having the same perspective as the human eye. Shorter lenses (usually 35mm or less) are considered wide-angle, which is good for fitting a lot of the scene into the frame—such as sweeping landscapes. Longer lenses (usually 70mm or greater) are considered telephotos, which have a narrower field of view to isolate the subject. Other special types of lenses include a macro (or “close-up”) lens, which lets the camera focus a lot closer to the subject, which results in a magnified (1×–5×) image. Note that no zoom lens is a true macro lens—even if the zoom lens has a “macro” designation—the typical magnification is 0.5× at best. Macro lenses are excellent for imaging small subjects, such as clasts, sedimentary structures, or small fossils.
For most geological uses, you can often find a zoom lens that will fill most of your needs as a “field lens.” For example, Nikon and Canon make an 18-200mm lens that provides adequate sharpness for geo-photography, and has a relatively close focus. Nikon and Canon also produce excellent 24-70mm zoom lenses that cost (and weigh) at least twice as much. In lenses, you get what you pay for, so investing in one higher quality lens is better than multiple cheap lenses. The sharpest images are usually obtained using lightweight “prime” lenses that are a single focal length and don’t zoom. (Common and very useful focal lengths are 24mm, 35mm, 50mm, 85mm) A prime lens, may be a good choice as a second lens rather than a heavier, inexpensive zoom that may produce poor image sharpness, color, and contrast.
The tripod. No matter how sharp your lens or how good your camera, shooting images while hand-holding your camera will result in just enough subtle blur to offset all that expensive equipment. If you anticipate taking important images, take a tripod along with you (and if you don’t, take the tripod anyway). Your tripod should allow you to spread the legs and shoot close to the ground for foregrounds and outcrops. Consider a tripod that allows you to position the column horizontally or upside-down to shoot outcrops and samples that you’ve placed on the ground. Lightweight carbon-fiber tripods can dampen vibrations (caused by the wind) and fold neatly into backpacks. Note, too, that if you are shooting with a lens that has image stabilization, you should, if possible, turn the image stabilization OFF when the camera/lens is mounted on a tripod for better image quality. (If image stabilization is left on, the lens will actually produce more shake as it tries to “stabilize” itself—even though it is securely mounted!) It is important to make sure that your tripod can support the weight of the camera and lens combination that you plan on attaching to it. Placing expensive camera equipment on top of cheap legs that buckle or topple is a hard lesson that happens all too frequently. Carrying along a tripod will provide you with the panache of a pro photographer, as well as making other people with cameras wish they had brought their tripods. Alternatively, a hiking staff with a removable screw-on top, on which you can attach a camera, makes a good stabilizing option for small DSLRs, micro 4/3 and compact/point and shoot cameras. It also allows you to boost the camera over your head, and, using the timer, and take shots of things seemingly out of reach.
Read the user’s manual. All the bells and whistles of a modern camera are useless unless you know how to use them properly. Although most cameras have standard settings, each camera manufacturer (and often, each model) has a different way of accessing those features.
You can never have too many batteries and memory cards.
Take a backup camera. This can be a point and shoot, or an iPhone, but take a second piece of equipment that can shoot pictures. Gravity happens. Batteries fail. Things get wet.
Use a lens hood. Not only does it block stray light, giving you better saturation and less flare, it also provides some cushion should you accidentally bump (or drop!) the lens.
Bring an umbrella or big plastic bag in case of inclement weather. Or be sure you have an extra-extra-large rain jacket that can accommodate your camera backpack and also shelter your camera while you are shooting in the rain.
Just as the quality of your results in research is dependent upon your attention to details, producing images that support and do justice to your work also benefit from the understanding of and attention to the technical details of photography.
Exposure is one of the most crucial details. There are three factors that effectively contribute to the final exposure: the aperture, shutter speed, and ISO (an adopted standard from the International Standardization Organization)—each of these factors affect the captured image differently. Aperture affects the depth of field (how much of the image is in relative focus)—the larger the aperture, the less parts of the image will be in focus. Shutter speed affects motion blur—slower shutter speeds introduce a greater amount of blur. ISO is a measure of the sensor’s sensitivity and noise—higher ISOs have greater noise.
A properly exposed image can have a variety of combinations of these three factors. It is through the use of these technical skills that the photographer can achieve their creative vision.
Digital cameras have many “auto” settings (auto exposure, auto ISO, auto white balance, etc.) meant to simplify things for the novice, or produce proper exposure for sports photographers and photojournalists who seldom have time to adjust everything between shots. However, the individual components of exposure also have significant effect (perhaps even repercussions) on your image. Your camera on “auto-anything” is a well-meaning partner that is totally ignorant of what you really want to capture. You may want everything to be in focus, from the rock in the foreground to the mountains far away. But if it’s evening or morning, your camera is likely to decide it needs a nice wide-open lens aperture, so it will happily shoot the scene at f/4, giving you (maybe) sharp focus on the rock, but the mountains will be a blur. For the best images, take control of your camera.
Aperture and Shutter Speed
The aperture of a lens, also called f-stop or f-number, is a ratio of the focal length divided by the size of the opening. The aperture controls the intensity of the light that passes through to the sensor. The lower the number, the wider the opening. So, f/2.8 is a much wider opening than f/22. It is important to be able to control the aperture setting because it allows you to isolate subjects or accentuate the focus of any given scene. The aperture also affects the shutter speed and ISO necessary for a proper exposure. In general, the wider the aperture, the faster the shutter speed and the shallower the depth of field. The maximum aperture (lowest f-number) of any given lens is usually inscribed on the lens, either around the front element or around the focusing ring.
Many lenses today can open up to about f/3.5 or f/4; the next full stop down is f/5.6, then f/8, f/11, f/16, f/22. In between these full stops are a myriad of intermediate stops. Some lenses can open up as far as f/2.8, f/1.8, or even f/1.2. Lenses with a low f-number are called “bright lenses” or “fast lenses” because they allow more light to pass through and so have more potential to shoot at faster shutter speeds. Fast lenses require a lot of glass, and are typically larger, weigh more, and cost exponentially more than slower lenses. For example, a 50mm f/1.8 lens costs about US$100, a 50mm f/1.4 lens costs over US$300, and a 50mm f/1.2 costs over US$1,400—and these are only half-stop differences!
The shutter speed controls the duration of the light that passes through to the sensor. Most cameras have a top shutter speed of 1/4000 s, with standard full stops of 1/2000 s, 1/1000 s, 1/500 s, and so forth—notice that each shutter speed is a doubling of the previous (stopping up). The lowest standard shutter speeds on most cameras are usually 30 s, with standard full stops of 15 s, 8 s, 4 s, and so forth—notice that each shutter speed is half of the previous (stopping down). Some cameras may also feature a “B” setting, or bulb, which leaves the shutter open for as long as the shutter release button is depressed—this is most often utilized in astrophotography, such as star streaks in the night sky.
In general, shutter speeds should be at least the inverse of the focal length on the lens to make sure a hand-held image have minimal blur. For example, an image shot at with a 50mm lens should be at least 1/50th of a second. A 200mm lens should be shot, handheld, at no less that 1/200th of a second.
Aperture and shutter speed have an exponential relationship to each other. For each “stop” decrease, say from f/5.6 to f/8, there is an approximate halving of the necessary shutter speed. For example, if a good exposure at f5.6 requires 1/60th of a second, the same exposure at f8 would require 1/30th, and the same exposure at f11 would require 1/15th of a second. Lenses usually produce the sharpest results when photos are shot ~3 stops down from their maximum aperture. This sharpness results because the light passes through the sharpest part of the lens. Stopping the lens down further, however, forces the light rays to bend and “diffract” and so decreases overall sharpness. In general, apertures of f/5.6-f/11 will give the sharpest possible image.
ISO is an abbreviation for International Standardization Organization. ISO is an adopted standard from the days of film, which describes the sensitivity of the camera sensor to light. In DSLRs, lower ISOs are least sensitive, have the greatest signal to noise ratio, and produce the clearest, most noise-free images, while higher ISOs are more sensitive, but the signal to noise ratio—and the image quality—also suffers. Most cameras have a native ISO of 100 (or 200 for Nikons), but can be et to ISO 200, ISO 400, ISO 800, and so forth—again, doubling the sensor sensitivity for each stop up. The noise inherent in high ISOs are better resolved by more modern camera processors— some are as sensitive as ISO 51200 or higher. In general, it is best to avoid using ISOs above 800 to avoid unwanted luminance or chroma noise. Images shot at high ISO (above ~2500) may look more like a painting, but better to have an artistic rendition than no image at all...
Getting The Right Exposure: Putting The Aperture, Shutter Speed, and ISO Together
Given these three variable factors, how we actually know the “proper” exposure for any given scene? The proper exposure is determined by a light meter, which is built-in to all modern digital cameras. The light meter measures the reflected light from your subject, be it a mountain or a hand sample, and calculates an exposure value (EV). Using the exposure ternary, we can creatively adjust our camera settings to capture our pre-visualized image.
For example, the camera meters a scene to be properly exposed at ISO 400, with a shutter speed of 1/60s at an aperture of f/8, or EV = 1/60s @ f/8 (ISO 400). [Keep in mind that this is not a math equation, but just used as a visual guide.]
Let’s say we decide to stop down the shutter speed to 1/125s to eliminate some motion blur and leave the other settings as is. Since the new shutter speed halves the duration that the light is passing through to the sensor, the resulting image is underexposed by a stop, or EV-1 = 1/125s @ f/8 (ISO 400). We can remedy this by either stopping up the aperture or ISO, by 1-stop to get back to the proper exposure, or EV = 1/125s @ f/5.6 (ISO 400) or EV = 1/125s @ f/8 (ISO 800).
Let’s say we want to only focus on a specific subject in the foreground and isolate it from the background. We do this by opening up the aperture (to smaller number) of f/4.0, which lets in 2-stops (or double-double, meaning 4x) more light, EV+2 = 1/60s @ f/4.0 (ISO 400). We need to change the shutter speed or ISO to accommodate for the change. We can either have EV = 1/250s @ f/4.0 (ISO 400) or EV = 1/60s @ f/4.0 (ISO 100)—or a combination of both, EV = 1/125s @ f/4.0 (SO 200).
Your camera’s built-in meter is interpreted by a processor, which has an image bank of common scenarios (e.g., landscape, sports, beach, portraits, etc.) that let it decide which of the three factors get priority over the others. In general, landscapes are given narrow apertures (high f-numbers), sports have higher shutter speeds, etc. In automatic mode, your camera makes these decisions in less time that it takes you to depress the shutter release button.
Keep in mind that the “proper” exposure (EV) that the camera calculates could also be off in special cases. Scenes of mostly white or light scene (high-key) or mostly black or dark scene (low-key) will be calculated incorrectly. This is because, in most cases, the camera assumes the scene has light and dark and calculates a middle gray to properly expose for both. If the scene is filled with mostly white (e.g., a glacier) or mostly black (e.g., a basalt flow), the calculated middle gray that will render the image too dark or light, respectively.
Depth of Field
Depth of field describes how much of the image is in apparent focus. It is a function of whether your image was taken with a wide or very small aperture. A photo in which features are in focus from say 5 feet to 50 feet has a greater depth of field than one in which features are in focus from 20 to 50 feet. In general, the smaller the aperture (larger f-stop) and shorter the focal length on the lens (e.g., 28mm as opposed to 50mm), the greater the depth of field. Depth of field is one reason why photographers often use tripods. A tripod allows a slow shutter speed, which allows a small aperture (larger f-stop), which allows for a deeper depth of field. A large depth of field can be useful for landscape images, where a sharp foreground leads the viewer’s eye into the background.
Keep in mind that most good photos have strong subjects— and a large depth of field can cause the image to look cluttered. A small depth of field, however, can help the subject stand out because all the extraneous material goes out-of-focus.
To isolate your subject with a blurred background, shoot at a wide-open aperture—f2.8 or smaller. This is why favorite professional portrait lenses are 85mm f1.4 or f1.2. They produce an exceptional blur known as the “bokeh.”
To include everything in focus, from the rock in the foreground to the distant mountains, use a small aperture of f11, and focus somewhere ~10-50 feet beyond the closest foreground subject.
Documenting Your Subject: Composition and Light
In geology, we observe landscapes on multiple scales. Among the most common, and germane to geo-photography, are (1) hand-samples or rocks close-up, (2) outcrops, and (3) landscapes. Each scale provides information that contributes to the subject. In geo-photography, capturing these three scales—often in one image—can be helpful in supporting our work.
Composition is the art of imposing visual order and structure on the random natural world. However, nature, including geology is often complex and messy. In contrast, the best compositions are often the simplest. Avoid visual clutter—elements that are in your field of view that do not actually support or reinforce the subject. When designing a photograph, always ask yourself why you are making the image and what you want to demonstrate to the viewer. Think graphically! Extract an image from the scene by using elements of graphic design, including color, lines, patterns, textures, and forms. Place these in an aesthetically pleasing manner within the photograph. Being aware of compositional elements, including layers, curves, folds, and other patterns will make your images much more compelling—and hence more effective at communicating your discoveries.
Here are some suggestions for creating engaging photographic compositions.
Simplicity. It is important to apply the suggestions below. But in using them, also keep in mind simplicity. Great images frame one subject and tell one story. Please do not make the viewer sort through visual clutter— extraneous blades of grass, buildings in the background, power lines—to see the subject of the image. Visual clutter distracts from your message. Keep images clean and clutter free.
Occupy the foreground. To make your image seem intimate, to involve your viewer in the image, make sure that the part of the image that seems closest to them is not a blank, wasted space (Fig. 5). Put something of visual interest in the foreground. When possible, place your subject, or something related to it, there. If you are shooting images of an outcrop, include part of the formation right up close to the viewer. Focus on it (or, preferably, just behind it), and use an aperture of f8 to f13 (any smaller and you will sacrifice overall sharpness in your photo). Use a tripod to guarantee sharpness. If you don’t have a tripod, brace your camera. Handheld images at less than 1/125th can be fatally blurred by inadvertent hand motion. As long as the foreground serves a compositional purpose—leading line, outcrop detail, etc.—it is not “visual clutter.”
Avoid putting everything—or anything of significance, including the most important element of the photo— smack-dab in the center of the photo. This practice leads to boring images, and our eyes often skip right over the center when searching for the “thirds.” (See below.)
Use the “rule of thirds” when composing your image. Imagine that your image is divided into thirds, both horizontally and vertically. You should place points of interest at or on the interior intersections of these lines. We often actually see or interpret things to have (like Gaul) three parts. If your image has three clearly defined parts (horizontally and/or vertically), it will often be more compelling to the viewer.
Lead the eye. Use available lines (or things that line up in the image) to lead the eye through the image. Lines that accomplish this may be the fractures in a rock face, bedding that leads the eye to distant outcrops, or clouds aligned in the sky that lead the viewer’s eye to the most important part of the image. Diagonal lines or elements are often more visually interest to the human eye than verticals or horizontals. Also, echoing geologic or l andscape textures in cloud patterns can also serve to lead the eye and add visual interest. Pay attention to shadows, as they also cast lines that direct or distract the viewers’ attention.
Hold the eye within the frame. Just as you want to lead the viewer’s eyes to your most important subject, it’s often a good idea to use visual elements to provide a “frame” for the image or to use vertical and horizontal elements in the landscape to trap the viewer’s eye within your picture. For example, placing trees at the edge of a landscape image of mountains provides a natural frame and bound the viewers’ eyes from wandering off of the image.
Avoid “dead” space, such as too much area with sky, or ground that is not important to your subject. The sky usually contains minimal geologic information, so minimize sky and maximize the geology—usually the foreground—in your shot. Cropping out dead space is a perfectly acceptable post-processing procedure, in case you notice a way to improve your composition after you’ve captured the basic scene.
Use depth of field to your advantage. Depth of field refers to how much of your image is in apparent focus. In most landscape photography and usually in geo-photography, it is important to have everything—or as much as possible—in sharp focus. You can achieve this with a small aperture (f11-f13; see no. 1 above). Sometimes, especially in shooting textures of outcrops, you may prefer to only have the part of the outcrop that matters in sharp focus. For this effect, you should shoot the image with your lens wide open. Note that compact cameras, with their small sensors, have relatively greater depth of field, and it may be difficult to achieve much blurring of the background, no matter how wide open your lens is. Professional lenses that are considered “fast” lenses often have maximum apertures of f/1.4 or even f/1.2 to achieve the effect of a blurred background.
Get close. Then get closer. This is a prime rule in photojournalism. You want your image to provide both intimacy and detail. You can’t do this if your subject is a tiny spot in the middle of the image. Move in. Zoom with your feet, not your lens. Shoot some images that may seem too close. Chances are these will be the ones you use. Try shooting images of just part of your subject to provide better detail. The beauty of digital photography is that if they don’t work, you have not invested much in taking them.
Try different perspectives. Photography, including geophotography, is part art and part science. While we want to provide the most accurate portrayal of our subject as possible, there is no rule that says images need be completely pedestrian. Nor should they all be shot from eye-level. If your subject is close to the ground, lie down and put the camera on the ground for your shot. If it is tall, get down on the ground and shoot upward. Make us see your subject as you see it, but also make us interested in the image for the image’s sake.
Groom your subject area, both physically and visually. Shooting an outcrop? Beware of grass or weeds or sticks that will distract from your subject. Look for errant plants, twigs, etc., that clutter the scene, and physically remove them if they are not a needed part of your image. Look also for distracting visual details—a phone pole sticking up in an awkward place, a distant building that will become a distracting white spot. You can often eliminate these by stepping a bit to either side, or shifting up or down, so that the offending distraction disappears behind a tree or shrubs.
Light is the essence of vision and of photography. Awareness of light is the most essential tool in terms of our aesthetic control when making a photograph. “Seeing the light”—being aware of the light and how its quality affects the perception of any subject—is critical. Slow down and watch how the light changes, whether it is a partly sunny day, with clouds—and light and shadow dancing across the landscape—or shadows deepening and colors growing more golden as the day ends.
Sunlight versus Shade; Noon versus Sunset
For photographing textural details of an outcrop, the diffuse light found in shade or on a cloudy day often provides better results than direct sunlight, where shadows may obscure or confuse the patterns. Landscape photographers are creatures of dawn and dusk because the low angle of the sun—and subsequent golden-hued light—reveal subtleties of landscapes. It’s also the best time of day to shoot dunes, ripple-marks, and other features where showing relief, whether great or small, is important. The warm sunset or dawn hues also impart a more romantic, pleasing light. However, to photograph a vertical surface (columnar basalts, Yosemite cliffs, etc.) the evening sunlight may provide little contrast, and important textures may be lost. Sometimes, vertical surfaces are better shot during the mid-day when the sun’s angle is low, compared to the cliff surface.
Directions of Light
The direction of the light that illuminates your subject provides an important character to your image. Generally light is one of three types. (1) Front, or direct light (what we consider “normally lighted” scenes) is light that is coming from behind the camera. (2) Side light is light that comes from the side of the camera and rakes across the subject, and tends to accentuate textures, landscape details—especially when at low angles (early morning or late afternoon). (3) Backlight is light that shines toward the camera. Backlit subjects (Fig. 6) often are illuminated by a halo of light. These images will be difficult to expose, and may also not reveal details of your subject without post-processing, but can also provide spectacular landscapes.
Most geo-photography is shot in daylight (except for specimens and photomicroscopy). There are several daylight-based light sources, and specific advantages to each. Direct point source—the Sun during bright cloudless days—provides high contrast. While this lighting may work well for broad landscapes, it often produces deep shadows and very bright, highly illuminated areas. If you are photographing details, the more uniform light produced by softer, diffused, low contrast light is a good option. Diffuse lighting includes the light on cloudy days, in shade, and light intentionally shaded. Reflected light tends to be more diffuse and produces less intense shadows and contrast than direct light. Reflected light is bounced from surfaces that are receiving direct sunlight. Reflections may come from other rock surfaces, buildings, or reflectors placed by the photographer (often useful to eliminate deep shadows in the subject). In addition, you may use a “fill flash”—a weak, low-intensity flash—to illuminate dark areas and eliminate shadows. Fill flash is often employed when shooting back-lighted subjects. A lot of macro photographers employ an external flash, because the lens often casts a shadow onto the subject due to its proximity.
The human eye is capable of resolving detail in ~11 “stops” of exposure when forced to look at one point without readjusting. When allowed to adjust rapidly to areas that are dark and areas that are very bright, the human eye can resolve detail in almost 24 “stops.” Most digital camera sensors cannot match this—they shoot at one setting. (Also, see High Dynamic Range, below.) Newer digital cameras such as the Nikon D800, Nikon D600, and Sony ALT S99 have dynamic ranges of 14 stops or more, approaching and even slightly exceeding the human eye at a fixed point. However, smaller cameras, including high-end compacts (Fuji RX100; Nikon Coolpix A, Canon S100) and smaller DSLR cameras with APS-C sensors (Nikon 7100, 5100, Canon D60, etc.), have greater difficulty resolving details in both highlights and shadows. While this limitation is not fatal, they are important when shooting high contrast outdoor scenes. You should consider whether things in shadows, or things brightly lit are more important, and expose accordingly. Note also that if you are shooting a RAW file, some additional details in shadows and/or highlights can likely be resolved in post-processing.
In geology, color may be crucial. In photography, color is an artifact of the light illuminating the subject. Under the cool wavelengths of a fluorescent light, a pure white quartzite may appear blue-green. Photographed during a sunset, it might be orange or reddish. And at high noon, under a clear sky, it might achieve its white color.
The color of light is known as the “color temperature.” In photography, we refer to correcting for the color of light (color temperature) as the “white balance” correction. Most cameras have specific settings for white balance: for example, cloudy (things will look blue) and fluorescent (things will look green). Most cameras also have an “auto-white balance” setting in which the camera determines the color temperature of the light hitting the sensor and adjusts the colors of the image accordingly. For convenience, this is the simplest to use. However, where color is critical, using a manual setting for the appropriate conditions is important. While colors can be corrected in post-processing, they are not as accurate as if the white balance was correctly tweaked when the image was taken.
Filtering the Light
You should always have a clear or UV filter on every lens. These inexpensive filters are great insurance policies that keep the front element of your expensive lens from getting scratched. The next most important lens is a polarizing filter (since light passes through the filter, it is also considered a lens). Geologic images, especially those of broad landscapes that include sky, or images shot in conditions of haze or humidity, are much improved by the addition of a polarizing filter. (If you have a compact/point-and-shoot camera that does not accept screw-in filters, you can actually hold a small polarizing filter up to the front of the lens without having to mount it, with much the same results as the bigger DSLR and MILC cameras.) Because a polarizing filter eliminates glare and randomly scattered light, the colors in your image will be more saturated and true than they would be without the filter. When you are shooting at 90 degrees to the position of the sun, your skies will also be much darker and more dramatic. Use of a polarizing filter requires that you manually rotate the front polarizing element until glare is optimally suppressed. The polarizing filter will also cut the light reaching your sensor by an average of 2-stops. While they are best used in well-lit scenes, a polarizing filter can help bring out colors in sunsets or late evening/early morning landscapes. There are plenty of other filters that may help improve your images, but these two (polarizing and a clear or UV filter) are generally all you need—and you do need them.
Photo File Format: Jpg Or Raw?
Almost all digital cameras, from compacts to professional DSLRs come with a default setting to produce images in a format known as JPEG (an abbreviation for Joint Photographic Experts Group, the organization that developed this now-standard digital image file format). JPEG, also abbreviated as. jpg files, are convenient because they are compressed. These are the small files so easily shared online. So, if you shoot. jpg files, you can download them from the camera and send them to someone else, or post them on your website without having to do anything. However, you really should downsize them first.
There is a mistaken idea that such seemingly unaltered images are a more scientifically accurate portrayal of the scene than an image that has been “altered” in post-processing. However, nothing could be further from the truth. The. jpg file that you download from the camera has been substantially tweaked by the camera’s software before you see it. So in using an “unprocessed,” straight out of camera (SOOC). jpg image, you are actually allowing the camera manufacturer to control post-processing for a variety of parameters, including colors, contrast, saturation, and sharpness. Each manufacturer has a slightly different formula. JPEGs from Canon cameras tend to be highly saturated, be shifted toward warmer, red colors, and of high contrast. Nikon tends to process for slightly cooler color balance and slightly lower contrast. While these are relatively subtle differences, they demonstrate that the unaltered. jpg is not an “unprocessed” photo. You have just deferred the processing to the camera, rather than yourself. On more sophisticated cameras, you have some control, through the menu, of how much contrast, saturation, and sharpening you want the camera to do. But not every camera allows this sort of collaboration or command.
To allow better control over the final image, high-end compact, all MILC and DSLR cameras allow you to save RAW files. This file is simply the data recorded by the camera’s sensor, with no in-camera processing. To formulate these data into an image, you’ll need a program called a RAW converter. Easily available and easy-to-use RAW converters include Lightroom, Aperture, and Photoshop, as well as the software that came with your camera.
RAW files are larger than. jpgs, include more data, and allow more and better corrections for exposure, color, and most other parameters. RAW files are 14-bit images; jpgs are 8-bit images. In post-processing (see below) you can recover details in highlights and shadows that might not be salvageable from a jpg. You have total control over the image, and in the end will produce a higher quality image than if you tried to achieve the same adjustments on a. jpg.
One great advantage of digital photography is the opportunity to fine-tune your image to improve its accuracy and detailed rendition of the subject. The camera captures only what its sensor is capable of, including a dynamic range that is more limited than the human eye, a composition that is defined by its 3:2 (or 4:3 in non-DSLR cameras) aspect ratio, and the inherent limits of its electronic and mechanical systems to render the scene. It is the geo-photographer’s job to go beyond the camera’s limitations, and produce a finished image that more accurately depicts what was intended.
The work of post-processing is nothing new to photography. In the pre-digital world, photographers overcame the limitations imposed by film chemistry and sensitivity by modifying exposure, shifting color chemistry and temperature, dodging and burning in the darkroom to reveal details otherwise obscure. It usually took many developed versions of the same image—and hence much wasted chemicals and photo paper—to get the image right. Ansel Adams was a master at producing print after print until he achieved the result he thought depicted the scene he had actually photographed. One of his guiding mantras was “The most important piece of equipment in the darkroom is the wastebasket.”
Cropping is a simple and non-invasive photo-edit that we often overlook. The best compositions retain simplicity, yet fill the frame with useful information that may not include a lot of sky, or un-needed foreground. There is nothing inherently sacred about retaining the camera’s native aspect ratio. Especially with cameras now shooting large files (16-36 MP), judiciously cropping your image to omit extraneous sky, a roadbed in the foreground or other distraction, is a perfectly legitimate procedure. It will help call attention to the significant aspects of your subject.
In geo-photography, we want to produce the most accurate rendering possible of our subject. But what the camera records in our digital file is often somewhat flawed. Some camera sensors are biased toward bluer or redder tonalities. Some provide great shadow or highlight detail, others give less overall dynamic range and need help in revealing what our eyes actually saw at the outcrop. Haze may obscure things. Our exposure of what matters may be too dark due to a very bright background. Or the standard rectangle of the digital image may leave too much sky at the top, or grass at the bottom to draw our attention easily to the subject at hand. Post-processing, done well, overcomes the technical flaws of an image, often producing a more realistic depiction of the subject than the camera captured initially.
With that said, the best images will be those with the least post-processing. Getting the framing and exposure correct in the field is very important and the mark of a photographer who is a master of the art and technical details. The quality of an image that uses the full extent of the sensor, without additional processing, is much better than the image that has been processed to achieve the same result.
Working With Raw (And Jpg) Files: Lightroom and Camera Raw
Adobe Lightroom is a post-processing software that has become an industry standard for post-processing RAW files. Similar software includes Photoshop’s Camera Raw (included in the full versions of Photoshop), Apple’s Aperture, DXO Optics Pro, and Capture One Pro. If your camera shoots RAW and saves files, chances are that the software that came with your purchase includes a RAW converter. However, Lightroom is among the least expensive, easiest and most intuitive to use, and also can open your converted RAW files in Photoshop if you wish. Light-room can also post-process jpg files, although with a jpg you have far more limited latitude for adjustment in any post-processing environment. All these programs, including Lightroom, are highly sophisticated image processing programs, and the discussion here touches only lightly on several very rudimentary operations. If you choose to shoot in RAW and employ a RAW conversion program, it would be wise to acquire and use an instruction book that goes beyond the manual included with the software.
Each RAW converter has its own protocol for importing or accessing files. To use Lightroom, you must import images into the Lightroom Library where they are archived—this is a sort of backup system for ensuring that your images are saved in more than one place. In Lightroom, you may also return your image to its original settings after you have processed it. Other software, including Photoshop Camera Raw, modify your original, and cannot be restored to original settings, so archiving your original RAW file is a good idea. Aperture saves your file into its own library like Lightroom, but other RAW converters do not.
RAW files are, essentially, digital negatives, that (like the old-fashioned film negatives) cannot be really seen or evaluated until they are developed or processed (Schewe, 2013). In Lightroom, or any other RAW conversion software, attention to only five parameters can vastly improve your finished image. This process requires only a minute or two per image once you become practiced in it.
Histogram (adjusting “levels”). The histogram, the graph at the top of the right-side menu in Lightroom, is a graphical representation of tonal and color data in your image. There are no “good” or “bad” histograms, but the ideal range of data would occupy all of the bottom line (tonal values). Otherwise, your image is missing or has overrepresented or minimized the presence of highlights or shadow values (known as “clipping”). You can adjust the histogram slightly so that the tonal information occupies the full bottom, and thus ensure that all the data your camera collected are represented (Fig 7).
White balance. Before you can properly adjust exposure and other parameters, the white balance (color temperature) of your image should be neutral. Remember that your camera’s sensor likely has a bias toward warm colors, cool colors, or other color factors that may not represent your subject with 100% accuracy. (Frankly, your adjustment might not either, but it may be better than the camera’s first instincts.) The easiest method in Lightroom is to use the dropdown menu and select a preset option (daylight, tungsten, etc.). This will require less than 30 seconds.
Exposure. This is a simple slider that adjusts the total amount of light in the image. On the slider, 1.0 equals one “stop” of exposure. Notice that beneath Exposure, you can also adjust related tonal ranges of contrast, highlights, and shadows.
Highlight-Shadow. Used judiciously, these sliders allow you to extend the dynamic range of your image by making dark, shaded areas slightly brighter and lighter, and bright places that seem over exposed darker so that you can see the details there. This is no different than the way we see things in the field as our eyes adjust rapidly to different lighting.
Sharpening. The files that your camera processes and provides to you as. jpgs not only have their colors and tonality adjusted for you, they also are sharpened by the camera’s software. Sharpening the digital file is a process of providing slightly increased contrast at the edge of each pixel. (This is distinct from lens sharpness, which provides the original definition of how well-defined each pixel edge is.) However, RAW files are NOT processed by the camera’s software. So you, the photographer, must provide some degree of sharpening. Lightroom automatically provides a default sharpening (a setting of 25 for RAW images). You may wish to sharpen more, but be careful not to over sharpen (generally avoid settings above 45-50).
Lightroom and similar programs are complex and offer a great deal of options and adjustments. As you become more familiar with the program, you may wish to explore and apply other options to correct and fine-tune your images so they accurately depict your subject. However these five adjustments will usually suffice. Note that you may also use the tools available in Lightroom and other programs to crop, straighten, remove spots, and many other useful operations.
Three Easy Jpeg Post-Processing Adjustments
If you are shooting JPEGs, you may adjust your images in Lightroom as well, but most often you will do post-processing in Photoshop, Photoshop Elements, iPhoto, or other program. On smart phones/iPhones, Snapseed works well. In only three steps, you can often improve your image.
Adjust the histogram (a.k.a. “levels”). In these programs, the histogram will have sliders on the left, right and center. Generally, the best image quality is achieved by moving the left and right sliders so they are beneath the tails of the histogram. Then adjust the middle slider (you are adjusting what value you wish to be “middle gray”) until your image looks correct to you.
Adjust contrast. This is helpful in cutting through haze, as are adjustments to vibrancy and clarity in newer versions of Adobe software (Fig. 8).
Adjust highlights and shadows. Judicious use of this tool will help reveal details that might otherwise be obscure and will also allow us to see the image as we would have seen the real thing as our eyes adjusted to differing light.
In addition to conventional field photography, this trip also offers the opportunity to learn and apply GigaPan photography. You will find the techniques discussed under Technical Details useful in setting up your GigaPan shoot. However you will be shooting only jpgs, and post-processing is not recommended before uploading the stitched images to the GigaPan site for viewing. GigaPans are high-resolution, gigapixel panoramas— digital images with billions of pixels. They are huge panoramas with fascinating detail, all captured in the context of a single brilliant photo. Once uploaded and posted on GigaPan’s website, the viewer can zoom into any portion of the image to resolve more detail. So, for example, on a GigaPan image of a ball game in Yankee Stadium, you can witness the entire ball-field at once, if not the stadium and field in the context of New York, and then zoom in to see whether Uncle Felix was in his accustomed seat, and whether he was eating popcorn or enjoying a beer.
To produce a GigaPan image, photographers use GigaPan’s EPIC robotic camera mounts to capture photos using almost any digital camera; GigaPan Stitch Software automatically combines the thousands of images taken into a single image; and GigaPan. com facilitates the unique mega-high resolution viewing experience. The GigaPan EPIC series of panoramic photography equipment is based on the same technology employed by the Mars Rovers, Spirit and Opportunity, to capture the incredible images of the red planet. Now everyone has the opportunity to use technology developed for Mars to take their own incredible images.
GigaPan was formed in 2008 as a commercial spin-off of a successful research collaboration between a team of researchers at NASA and Carnegie Mellon University. The company’s mission is to bring this powerful, high-resolution imaging capability to a broad audience. The original GigaPan prototype and related software were devised by a team led by Randy Sargent, a senior systems scientist at Carnegie Mellon West and the NASA Ames Research Center in Moffett Field, California, and Illah Nourbakhsh, an associate professor of robotics at Carnegie Mellon in Pittsburgh.
Field Trip Guide
This one-day field trip will provide introductions to the three principal sedimentary formations exposed at Roxborough State Park (http://www.parks.state.co.us/parks/roxborough/Pages/RoxboroughStatePark.aspx). The trip’s principal objective is to discover, observe, and document geologic features and settings through photography at multiple scales. Our precise stops may vary slightly from the locations noted here. You will have the opportunity to work with each of the trip leaders during the day.
Stop 1: Fountain Valley Overlook
Our first stop will be at the Fountain Valley Overlook, close to the Roxborough State Park Visitor’s Center. Here, you’ll receive an introduction to park geology, a brief synopsis of available equipment, and we will divide into four groups. From this point, the Dakota Hogback, of mostly Cretaceous Dakota Sandstone is nearby and accessible. Features for photography and discussion include ripples, trace fossils, and faulted/fractured surfaces.
Stop 2: Fountain Valley Trail
Along this 2.3-mile trail, depositional environments and textural details of the Pennsylvanian Fountain Formation are emphasized. These will include: conglomeratic textures, sand polygons and dikes, mudcracks, stream channels. We will refine our techniques for compelling close-ups of rock details. The challenges will include incorporating these features to depict the overall Fountain Formation petrogenesis and tectonic settings, as well as attention to principles of composition in geo-photography.
Stop 3: Lyons Overlook Trail
The Lyons Formation’s challenges include deducing its origin as fluvial, dunal, or shoreline deposits, and as such both details and outcrop-scale images are important. We will look for tracks and trackways, trace fossils, ripples and other evidence of the sedimentary origin of the Lyons Formation, with practice in use of filters, and a variety of focal lengths to optimize images and information.
Stop 4: South Rim Trail
This walk provides overviews of much of the park, and as such, is an excellent opportunity to capture full landscape views. The challenge is to document how sedimentary, erosional, and tectonic history contribute to the landscape we find in front of us.
Stop 5: Choice of trail
Depending upon your interest, this will be an opportunity to explore, examine, and pursue your particular interest, with the objective of contributing your images and findings in the morning session tomorrow.
Stop 6: Visitor Center
A review of park geology, and time for comments, and review of some techniques that you found most helpful.
The 2013 trip during the GSA Annual Meeting in Denver concluded with a post-processing session the following day, where participants had time to process and share photos. Other discussion included:
GigaPan stitching and uploading.
RAW post-processing in Lightroom and Camera Raw.
JPG post-processing in Lightroom.
Use of Photoshop and Photoshop Elements to refine and optimize images.
Working with file sizes and changing file sizes.
Reviews by Jefferson Chang, Gregory Hancock, and Ted Sayre were extremely helpful in clearly presenting the information in this field trip guide.
Suggested Further Reading
There are many, many books and websites on photography that can provide more details and greater insight beyond the contents of this field guide. Here are several of our favorites.
Aris, Zack, 2013, Photography Q&A, New Riders, 312 p.
Long, Ben, 2012, Complete Digital Photography, 7th edition, Cengage Learning PTR, 640 p.
Rowell, Galen, 2012, Mountain Light (Sierra Club edition), Sierra Club Books, 240 p.
Rowell, Galen, 2010, The Inner game of Outdoor Photography, W.W. Norton, 287 p.
Schaefer, John, 1998, The Ansel Adams Guide: Basic techniques of photography, Little, Brown, 400 p.
Tharp, Brenda, 2010, Creative Nature and Outdoor Photography (revised edition), Amphoto Books, 160 p.
Wolfe, Art, and Martha Hill, 2013, The New Art of Photographing Nature: An Updated Guide to Composing Stunning Images of Animals, Nature, and Landscapes, Amphoto Books, 224 p.
Figures & Tables
Classic Concepts and New Directions: Exploring 125 Years of GSA Discoveries in the Rocky Mountain Region
- Dakota Formation
- data processing
- Douglas County Colorado
- field studies
- field trips
- Fountain Formation
- Front Range
- Lyons Sandstone
- North America
- public lands
- road log
- sedimentary rocks
- United States
- upper Paleozoic
- Western Interior
- Western Interior Seaway
- Roxborough State Park