Photography Tips – Exposure Metering

Correct Exposure is The Exposure You Want

The Camera Light Meter

Is a sophisticated but mindless tool

Sometimes right, sometimes wrong

But even when right,

It can’t read your mind

Yearning for Spring

The exposure I wanted ;-), a 10-shot multiple exposure

Dogwoods & Redbuds – Shenandoah NP April 2011

Already a few cherry blossoms – in mid-February 2012???

Crazy weather

Today’s cameras contain excellent light meters – some better than others but all excellent.

1. Your camera’s light meter measures light (duh) and

2. Based on the measurement, it recommends exposure setting alternatives

Which depend on –

The exposure mode you’ve selected (manual, aperture priority, automatic, etc.)

The metering option you’ve selected (matrix, centered, spot, etc.)

The settings provided are f/stop & shutter speed combinations any of which will give a theoretically correct exposure

f/16 @ 1/100 sec, or f/11 @ 1/200, or….

In the simplest terms that’s all that it does –

provide aperture and shutter settings for a “theoretically correct” exposure (TCE) –

TCE = exposure settings that result in an overall image tonality of middle gray

What is a correct exposure? (not “theoretically correct”)

It’s the exposure that you want

and the light meter can’t read your mind!

It’s designed to do just one thing, provide the TCE

but – you may not want TCE even if it’s right

or – the TCE may be wrong, fooled by the conditions

You may want a high or low key image.

The meter doesn’t know how to do this without your intervention.

You will have to compensate by adjusting exposure compensation for example.

Or, you may want white snow.

The meter wants the tonality of the overall scene to average out to middle gray – and is fooled.

You may have to increase the exposure compensation to compensate and make your gray snow white.

Or, you may want detail in a blackbird silhouetted against a bright sky

Depending on your meter mode selection the bird may be far from black (and without detail)

Such as when your mode selection includes the sky

You’d better spot meter on that blackbird

Enlarge for detail

Without spot metering, a black silhouette

And on & on….

such as a scene’s tonal range exceeds the sensor’s capability –

either expose for the dark or for the bright and accept the consequences, or

shoot several exposures for HDR, or

try a grad neutral density filter

Bottom line, the light meter is a sophisticated one-trick pony.

Often that trick isn’t the one you want or need

You have to know how to compensate, usually by some combination of

1. Adjusting exposure compensation and|or

2. Selecting the most appropriate metering mode

The dedicated photographer will learn to do these things –

instinctively & automatically

practice, practice, practice.

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0 thoughts on “Photography Tips – Exposure Metering”

  1. With the large number of readers, some of my topics aim too high and others too low possibly. One like today’s is useful for students, as you noted, and is hopefully a useful reminder for those more experienced.

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