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!)
Put a roll of 100 ISO slide film in your Nikon F-4 (F4)
camera 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. To avoid
confusion, in this exercise we will increase and decrease the exposure by opening-up and
closing-down the aperture. The shutter speed will remain fixed.
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 and you are
using slide film, pick out a tone that is medium gray or brighter. If you are using a
negative film, pick out a tone that is medium gray or darker.
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 opening 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.
The image tone that your normal exposure provides is independent of the original tone of
your subject. It is extremely important that you understand this point. The following is
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. Closing- down the
aperture by two stops converts the 18% gray image tone to Black. The correct exposure is
If you chose Dark Gray, you
need to decrease the "normal exposure" setting by one stop. Closing- down the
aperture by one stop converts the 18% gray image tone to Dark gray. The correct exposure
is now of 125@f-11.
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.
If you chose Light Gray, you
need to increase the "normal exposure" setting by one stop. Opening-up the
aperture by one stop converts the 18% gray image tone to Light Gray. This results in a
correct exposure of email@example.com.
If you chose White, you need
to increase the "normal exposure" setting by two stops. Opening-up the aperture
by two stops converts the 18% gray image tone to White. The correct exposure is now