BetterPhoto Q&A
Category: New Answers

Metering

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December 27, 2006

Just kidding, of course.

In the digital age, with the advent of cameras with monitors, a camera owner can put the camera in auto-everything, press the button, and keep adjusting exposure until it looks good on the monitor. And a number of photographers find that works for them.

Being from the transparency film days, metering was critical. The good thing about that is that metering in the digital age is pretty much the same as metering for transparency film (although I've learned to underexpose 1/3 to 2/3 stop to get the same exposure that I got with film).

To me, metering is nothing more than getting an exposure that works. The KEY to exposure (again, in my opinion) is to internalize what an average tonality is.

The question that I always ask students in terms of exposure is, "Which is the brightest color: red, blue, yellow, green?" The answer is almost always, "yellow." The student says that because yellow appears to be brighter, so one would open up (slightly over-expose) when metering a yellow tonality, as opposed to a blue tonality subject, for example. In actuality, if you pass a light meter, like your in-camera meter, over 18% blue, then over 18% red, 18% green, and 18% yellow, the meter will remain constant. The point here is that you are reading color reflectance, not the color itself.

Learning average tonalities is key to learning brighter and darker tonalities. When you learn or get a feel for average tonalities, you can key off of that reading to over and/or underexpose your subject/scene to get the "proper" exposure.

Luckily, with the exception of high contrast scenes like sunrises, sunsets, and scenes that include bright skies, most subjects are in the average range (maybe a bit brighter or darker), and can be easily adjusted in software.

You referred to metering a blue sky for an average tonality and that will certainly work, but be aware that it means to meter the dark blue part of the sky early or late in the day. Other average tonalities can be tree bark, green grass, blue jeans.

Faces of caucasian people can be metered at plus 2/3 brighter than average. Faces of darker complexion people can be metered at average (since digital tends to underexpose) to minus 1/3. These are ballpark exposures, and may need to be adjusted.

NOTE: Using flash is a whole other ballgame and the exposures discussed here will not apply.

NOTE 2: In general, modern flash systems and modern digital cameras take a lot of the guess-work out of general purpose flash photography. I find that using my Nikon D200 and D2XS on Program mode, matrix metering, and setting the flash to TTL, renders excellent family pics or general candids.

What do I do?

I’ll use all metering systems in the camera based on subject material and speed.

IMPORTANT: I always use a tripod for serious professional work.

Matrix metering: I’ll let the camera give me an overall average reading and will adjust using the exposure compensation dial if I feel that scene is brighter or darker than average. OR, if I want to interpret the scene as darker or lighter than it really is.

Center-Weighted metering: I’ll use this on occasion, mostly on macro images, where the large center area is about the same tonality. I’ll adjust the shutter speed since a great deal of my work is aperture priority (f/stop is much more critical than shutter speed).

Spot metering: This is the same idea as center-weighted, but applies to a much smaller area. Actually, it’s easier to find smaller areas of similar tonality than larger areas.

I use matrix and spot metering on 99% of my images.

So, to answer you specific metering situations:

Meter the dark part of the blue sky during early morning and late afternoon to get an average tonality.

For white snow or any white subject, let in more light (since white is brighter than average, right?). So, try over-exposing by 2/3 stop to see how you like the exposure and adjust accordingly.

GENERAL RULE: Meter your subject correctly and everything else will fall into place IF everything else is in the same light. If the sky is brighter than the foreground, you’ll need to use a graduated neutral density filter, shoot two exposures and blend in software, or any number of digital techniques to balance the sky and foreground.

CONCLUSION: The key to fast and accurate metering is to know what an average tonality is and then let in more light (over-expose) or let in less light (under-expose) to get the exposure that works for you.

I hope that this begins to answer your question. If not, feel free to follow up in the Q&A.

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December 27, 2006

Your grandfather took great pictures using a “Brownie” box camera, names after the woodsy characters made popular in the Canadian comics that decorated the packaging. Granddad was restricted to pictures taking opportunities between 10AM and 4PM on sunny days. Advances in camera design expanded the picture taking circumstances to most any time of day or night. With these advancements came the troublesome aspects revolving around the question, “what settings do I use?” At first we only had trial and error and tables that suggested the settings. In the nineteen thirties electric light meters became available. Their prime purpose was to measure and evaluate scene brightness and relate these values to camera settings. The light meter evolved to a unit attached to the camera and then became interconnected. Now the meter is embedded into the camera. Many advanced photographers retain the use of an independent instrument. They talk about ways to meter (measure) the subject and how to interpolate this data. They often taking multiple measurements and using their own experiences to manipulate the data. Always the objective is to set the camera controls for correct exposure and artistic effect. Your camera has both manual and automatic setting capability. Your camera features advanced metering using chip logic. In “auto” it can evaluate 35-zones and using weighted averaging set the camera controls for you. You can elect to set the camera using different modes including overriding in complete manual. You have a camera that takes advantage of years of engineering experience. Now you need to study and practice and maybe fame and fortune waits.

Happy New Year and good luck,

Alan Marcus
ammarcus@earthlink.net

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December 27, 2006

With the subject in mind, creative composition can be utilized to exclude the hot spots and deep shadow areas in most cases.

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December 27, 2006

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December 27, 2006