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Photography Question 

Double exposure

I'd like to take a photo of an individual standing against a prop inside wearing one outfit, then another exposure on the same frame slightly overlapping the first. Do I have to make any adjustments in exposure when against a black background

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3/12/2003 6:39:54 PM

John A. Lind
BetterPhoto Member Since: 9/27/2001
I don't know about the overlapping part. There is an exposure issue with that.

The general method for doing this mounts the camera on a sturdy tripod and uses a rotating square filter holder that mounts on the front of the lens. A remote or cable release is highly recommended for tripping the shutter to keep from moving the camera. You must also manually set exposure, or be able to lock in an exposure. Obviously, your camera must allow multiple exposures, or you must be able to reliably cock the shutter without moving the film.

The camera is mounted to the tripod, aimed for the scene that will be used for both sides of the imamge, and the remote/cable release is attached. Instead of inserting a square filter into the filter holder, a flat black panel is used. This panel is then inserted into the filter holder so that it blocks half the lens. The first half of the image is composed and shot. Then the filter holder is rotated 180 degrees to cover the other side of the lens with the panel. The shutter is cocked very carefully (to keep from moving the camera) *without* winding the film to the next frame. The other half of the image is then composed and shot.

Because you are exposing each half of the film frame only once, no exposure compensation is necessary. However, unless you are doing this in a studio with studio lighting (metered with a flash meter), or meter with a hand held meter (outdoors), you are pretty much left with metering using the built-in meter on your camera. If you do use the camera's internal meter, manually set exposure . . . or lock the exposure setting with it (if your camera allows this) . . . *before* covering half the lens! If you try do to this using TTL automatic metering control from the camera (with a dedicated flash), or do this outdoors using TTL auto exposure control, you will grossly overexpose both sides. Why? Half the film frame is essentially black and your metering will make up for this by setting an exposure between the illuminated side of the frame and the totally black side. IMHO, manually setting the exposure works best.

If you camera is a manual wind *and* rewind, but doesn't have a multiple exposure switch:

You can still shoot multiple exposures, but it is a bit more difficult and not without some risks.
1. Put on lens cap, shoot a blank frame, and advance to the next frame.
2. Fire the shutter again with the lens cap on. While depressing the film rewind button (unlocks the film transport for manually rewinding the film), and holding the rewind crank still, cock the shutter using the winding lever. This will tension the film inside the camera so that the next time you do this, it won't move.
3. Remove the lens cap, mount the filter holder on the lens, and proceed to shoot the first side as described above.
4. While depressing the film rewind button, and holding the rewind crank still, cock the shutter again using the winding lever.
5. Shoot the other side of the frame as described above and advance the film as you would normally.
6. Remove the filter holder, put the lens cap on, shoot another blank frame, and advance the film once more.

Essentially you are puting a blank frame on each side of the double exposure. With many cameras (without multiple exposure switches), if you don't do this, there is a risk that one of the frames adjacent to the multiple exposure will overlap with it, ruining both frames. This isn't a sure fire method. There is still risk of the film moving slightly. Make two or three shots of your double exposure until you become very confident you've got this down pat and that the film will never move on you when doing it.

-- John

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3/14/2003 8:13:08 PM

John A. Lind
BetterPhoto Member Since: 9/27/2001
  Ooops . . . forgot to explain why you don't want to try to overlap the two sides of the image. If the two sides overlap, you will end up with a very noticeable strip in the middle that is overexposed (been there, done that . . . accidentally . . . it ain't very pretty).

-- John

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3/14/2003 8:16:49 PM

John A. Lind
BetterPhoto Member Since: 9/27/2001
Forgot one more thing . . .
The two major manufacturers of rotating filter holders that have panels for doing this are Cokin and Lindahl. The Cokin system is less expensive and well made. There are two sizes; I recommend the larger of the two (the smaller is harder to work with). The Lindahl is a more expensive high end pro system built like a tank.

-- John

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3/14/2003 8:22:07 PM

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