"It seems an utter impossibility to get the proper condition. Long focus lens with a good shutter, a wide angle lens, and an Astigmatic will be o.k. with a trip in the summer or fall."
Catalog from Whitmore Exploring Expedition, 1897; Grand Gulch, Cave 8.
Photography is a great way to record rock art, but the effects of time and weathering often make it difficult to get a good image. Usually you can get an acceptable result by combining multiple film types and bracketing your exposures.
EQUIPMENT:
FILM:
EXPOSURE:
TIME of DAY:
FILTERS used in Black & White photography:
FILTERS used for color photography:
Be careful using filters with wide angle lenses, vignetting becomes a problem with 24mm and wider lenses.
To avoid blur on handheld exposures, use a shutter speed at least as great as the focal length of the lens being used. For a 200mm lens, shoot at 1/200 of a second or faster.
Shoot ruins in full shade for best results.
Cloudy & rainy days are the perfect times for macro photography (and lots of other kinds too). The light produces warm, saturated colors.
You can slightly under expose slide film (very little latitude here). Color print film can be over exposed as much as 6 stops and still produce a print.
Keep your film and camera as cool as possible. Heat damages film.
Carry extra camera and flash batteries.
COMPOSITION TIPS:
Fill the viewfinder with the image you want. Don't stand too far away.
Do you really want to include the feet of your subject?
Use a long (telephoto) lens to extract the image you want from a cluttered background. Keep backgrounds simple!
Use a large lens opening to blur out distracting backgrounds. Telephoto and macro lenses give selective focus without the use of a large lens opening.
Usually it's not good to place horizon through the center of the photograph.
The Rule of Thirds recommends dividing the photo in thirds both horizontally and vertically. Your subject is centered near one of the intersections of these divisions.
Sunny f16 rule for estimating exposure: With clear skies, and the sun at elevations greater than 15 degrees, the Sunny f16 Rule is that the exposure can be set with the f-stop at f16 and the shutter speed at the ASA rating of the film. For example, with an ASA of 100, the shutter speed would be set at 1/125 for B/W films and 1/60 for color film. These are the closest shutter speeds usually available on cameras.
The following combination of f-stops and shutter speeds all expose the film the same. The different combinations provide either better depth of field (sharpness) or reduced blur due to camera shake. A tripod or monopod helps get the better depth of field with reduced shutter speeds in reduced lighting situations.
Sharpness least ---- ---- ---- ---- ---- ---- ---- best Less blur best ---- ---- ---- ---- ---- ---- ---- worst Shutter Spd 2000 1000 500 250 125 60 30 15 8 f-stop 1.4 2 2.8 4 5.6 8 11 16 32
Exposure of film using a 18% Gray Card. The gray card is intended to make reflection-light meters (those included in most cameras) as incident light meters. The normal camera meters sets exposure based upon an average scene. An average scene is one in which an average of all light and dark tones equals a middle gray like the gray card.
To use the Gray Card for setting exposure:
If you don't have a gray card, pick the area that you want to be medium gray and meter this area. Good substitutes for a gray card are green grass and the northern blue sky.
See An Etiquette for Visiting the Cedar Mesa Area.
Return to Cedar Mesa home page.
- URL of this page: http://bcn.boulder.co.us/environment/cacv/cacvphot.htm
- Revised '9-Jun-2001,11:10:14'
- Copyright ©1996, 1999 SCCS.