ExpoImaging ExpoDisc Reference Manual for Digital Cameras - Manual (Page 11)

ExpoDisc Instruction Manual
v. 4.0. 05/06
11
2.d. Metering for Exposure with the ExpoDisc
Today’s digital SLR cameras capture an image with a similar dynamic range as
yesterday’s Kodachrome 64 color slide film, for which the ExpoDisc was originally
designed. The method for using the ExpoDisc as an incident exposure tool was initially
developed to compensate for the limited dynamic range of the capture medium. The
result is a tool that requires decisions over whether to expose for highlights or shadows
in high contrast lighting, and to make adjustments as necessary. When used correctly,
you should expect to be within 1/3 stop of correct exposure.
2.d.1. Front-lit Subjects
This category includes all front-lit and uniformly-lit subjects and scenes in which there
are no significant highlight or shadow areas.
1. Stand in the same lighting as your subject (although not necessarily beside it) and put
your camera in its manual exposure mode and mount your ExpoDisc in front of the
camera.
2. Then point the camera and ExpoDisc in the direction directly opposite that in which
you will be shooting to make the exposure.
3. Turn on the camera meter, adjust the aperture and/or shutter speed settings until the
camera meter indicates good exposure conditions.
4. Return to your shooting position (if you left it to do your metering) and remove the
ExpoDisc from in front of the camera lens.
5. Aim the camera, check the framing, and shoot.
2.d.2. Side-lit Subjects
These include all subjects and scenes in which there are significant highlight and
shadow areas, and in which the highlight areas are most important.
Follow the procedure described for photographing front-lit subjects, but after pointing
your camera and ExpoDisc directly away from the subject and before adjusting the
exposure settings, swing the camera and ExpoDisc about one-third of the way towards
the main light source.
2.d.3. Back-lit Subjects
This category includes all subjects and scenes in which there are significant highlight
and shadow areas, and in which the shadow areas are most important.
Follow the procedure described for photographing front-lit subjects, but just before
clicking the shutter, reduce the exposure one full stop, to provide for appropriately
darker-than-normal image tones in the shadow areas.
3. Troubleshooting
3.a. Camera and Hardware Specific Issues