Nikon F-4 (F4) - Technique

"One of the easiest-to-understand books on exposure and the Zone System that we've ever seen"

Outdoor photographer Magazine

If you do not want to read the book titled "the confused photographer's guide to photographic exposure and the simplified zone system ISBN: 0966081714" simply read the following:

The on-camera or off-camera spotmeters (spot meter) are the most powerful exposure tool in the world. However, before you can use them you must have a basic understanding of the Zone System of light measurement. Read the following page and decide for yourself if you understand the concept. If you do understand everything on the following page, and you can apply the technique described, then that is all you need (well almost!)
If, however, you even have the slightest doubt about this technique, or you do not understand why, the confused photographer's guide to photographic exposure and the simplified (non technical) zone system is for you.
I believe this is the simplest, easiest, best illustrated, and most practical book about the photographic exposure, the simplified zone system (non-technical), incident metering and off-camera spotmetering in the world. To see more of the book and what you will be learning, please browse:

http://www.simplifiedzonesystem.com

or send an e-mail to
cpgbooks@spotmetering.com

Cheat sheet: The entire book condensed onto one page (well almost!). To see what is exactly covered, please see the Appendix at
the Simplified Zone System book

Put a roll of 100 ISO film in your Nikon F-4 and choose an outdoor subject. Activate the spotmetering option on your F-4 and set your camera’s mode to manual and to the shutter sped to 1/125 sec. To avoid confusion, on this page 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 usually chosen from the most important part of the subject. Once you have selected the Reference Tone, point your spotmeter located at the center of the viewfinder (in the F4's case, one of the five 4mm-diameter spots which may not have a distinct spot frame (circle)) 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.
Let’s 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 spotmeter’s "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.
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 subject’s"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 accordingly:

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 now 125 @ f-16.

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
(125 @ f-8) 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 125@ F-4.6.

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 125@F-4.