BetterPhoto Q&A
Category: New Answers

Photographing a White Dog in Snow

Thanks in advance!
Kristy

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January 13, 2008

I would shoot RAW(+JPG) and bracket, so that I 1) can adjust WB in PP, after the fact, and 2) have a range of exposures to choose from/work with.

I would also try a few exposures with fill-flash. They might surprise you.

Don't skimp on the number of exposures you take. The more the better (for choice).

Alan and John may possibly be along next with some more useful advice.

Have fun!

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January 13, 2008

All modern cameras sport some form of built-in-metering. Improvements in miniature light-measuring components and their associated chip logic and software have almost, but not quite rendered obsolete the hand held light meter. When using a hand meter one simply points and receives a general reading that is only satisfactory if the scene integrates to middle gray. Years ago Kodak research labs concluded that most scenes if optically scrambled amalgamate to a single tone approximately 18% gray (battleship gray). Their early recommendation; “place a yellow Kodak paper packaging envelope in the scene illumined as the principal subject and take a close-up light meter reading, set your camera as indicated”. It worked! The logic was, this box reflected about 18% of the ambient light impinged upon it. In the 1940’s the famous landscape photographer Ansel Adams and his colleague Fred Acher (editor US Camera) refined this procedure using a placards with 18% gray surface.

The gray card method became what I call a “self-eating watermelon” because film makers adopted this tone as an aim point. Scientifically the tone 18% gray is most often written as 0.75 Red – 0.75 Green – 0.75 Blue (the values of such a tone as read using a modern film/paper measuring instrument known as a densitometer). This reference tone is universally used by every photofinishing lab in the world as a standard (often bumped up to .80R .80G .80B as a reference aim point for the color print the added .05 density making the production output slightly darker. Additionally this tone is a calibration standard for nearly all light measuring systems photographic and scientific.

Thus you too can use a gray card. Taking a reading from a gray card placard held next to the white dog on white snow is a valid technique. Many hand meters have an incident mode whereby a white diffusion dome covers the meter cell. In this mode the meter is pointed backwards (from the subject back at the camera). This reading known as an incident reading simulates a reflected reading from a gray card. The incident method is a favorite in Hollywood for motion picture exposure determination as exposure error is quite costly.

Alan Marcus, Anaheim, CA (marginal technical baloney)
ammarcus@earthlink.net

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January 14, 2008

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January 14, 2008

Postscript:
The white dog did not look dirty due to white balance error! Since the exposure meter system is calibrated to reproduce middle gray with fidelity, the meter did its job and the white dog reproduced too dark (as an 18% target). Since white is a natural color and snow too is natural color, the error is likely exposure and not white balance.

A valid technique is to reflection read your own palm. Fair human skin is more reflective than a gray card by 1 f/stop. Thus a fair complexion reading requires a minus one f/stop adjustment (open up one f/stop). Medium complexion, no correction required, lucky you, you have your own personal gray card. Dark complexion, plus one f/stop does the trick.

Alan Marcus (more trivia)

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January 14, 2008

iso 100 or 200: you'll possibly have plenty light, so take advantage of that to convert it into image quality, low noise.

Av aperture priority: set according to the DoF (Depth of Field) you want.

Working from tripod always markedly improves image quality.

I would spotmeter off the dog, and adjust +1 for it being white(ish). Bracketing will save your bacon.
It will also, if from tripod, provide you with a range of originals that the HDRI technique (High Dynamic Range Imaging) can be applied to if you want really brilliant images.

Good luck tomorrow!

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January 14, 2008

Kristy

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January 17, 2008