If you do not want to read the book titled
"the confused photographer's guide to on-camera spotmetering (spot metering / partial
ISBN: 0966081706" simply read the following:
The on-camera spotmeter (spot meter /
partial meter) is the most powerful exposure tool in the world. Read the following page
and decide for yourself if you understand the concept. If you do understand everything
on the next page, and you can apply the technique described and produce correctly exposed
images, then that is all you need! If, however, you even have the slightest doubt about
this technique, or if you are still the least bit confused, this book is for you.
Remember: either you know how to use your on-camera spotmeter effectively or you
dont. There is no in-between! I believe this is the simplest, easiest, best
illustrated, and most practical book about on-camera spotmetering in the world.
Cheat sheet: The entire book condensed onto
one page (well almost!)
Set the ISO of your CoolPix
990 to 100 and choose an outdoor subject. Activate the spotmetering option on your camera
and set your cameras mode to manual and to the shutter sped to 1/125 sec. Set
your CoolPix Image Adjustment to Black and White:
(MENU 1 » IMAGE ADJUSTMENT » Black&White)
Observe your subject and break
it down into its simple subject (single tone) components. Choose a Reference Tone. A Reference Tone is a simple tone usually chosen from the
most important part of the subject. Once you have selected the Reference Tone, point your
spotmeter at this tone and find its normal exposure. If your subject does not have a
distinct single tone pick out a tone that is medium gray or brighter.
Lets assume the
"normal exposure" indicated by your camera for this Reference Tone is 125@f-8
(i.e., 1/125 sec. at an aperture setting of 8).
As you may know, the spotmeters "normal
exposure" from any simple (single toned) surface will always provide the photographer
with an 18% gray image tone (or a Grayscale density of 128 (out of 256) in photoshop on
your home computer).
The image tone that your normal exposure provides is independent
of the original tone of your subject.
In spotmetering, converting
the "normal exposure" to the "correct exposure" is what a photographer
must do. In other words, the "normal exposure" readings of the spotmeter must be
interpreted by the photographer to determine the subjects"correct
exposure." The principle behind this simplified technique is that if one tone of a
complex subject is exposed correctly, the rest of the tones follow and will also be
correctly exposed . Now decide which one of the following tones would most closely matches
your Reference Tone: Black, Dark Gray, Medium Gray, Light Gray or White. With this
simplified technique you must choose one of these five tones. Once you have decided which
one of these five tones best matches your Reference Tone, then adjust your camera settings
If you chose Black, you need
to decrease the "normal exposure" setting by two stops. Decreasing the exposure
time by two stops converts the 18% gray image tone to Black. The correct exposure is
now 1/500@f-8 or equivalent.
If you chose Dark Gray, you
need to decrease the "normal exposure" setting by one stop. Decreasing the
exposure time by one stop converts the 18% gray image tone to Dark gray. The correct
exposure for this is 1/250@f-8 or equivalent.
If you chose Medium Gray,
leave the aperture and shutter speed as they are since the meter is already creating an
18% gray (Medium Gray) image tone, i.e., the tone of the image matches the approximate
tone of the Reference Tone. Also remember that when metering from a medium gray surface,
the "normal exposure" and "correct exposure" settings are
approximately the same. In this case the correct exposure is 1/125@f-8
If you chose Light Gray, you
need to increase the "normal exposure" setting by one stop. Increasing the
exposure time by one stop converts the 18% gray image tone to Light Gray. This results in
a correct exposure of 1/60@f-8 or equivalent.
If you chose White, you need
to increase the "normal exposure" setting by two stops. Increasing the exposure
time by two stops converts the 18% gray image tone to White. The correct exposure would be
1/30@f-8 or equivalent.