I was just reading through the DQ guide and noticed someone mentioned that multi-exposures were allowed, but I was a little confused as to how that is done with a digital ?(I know my camera is rather low end is it just an option on higher end Digitals ?)
A question if I might about the X-ray image... in the DQ voters guide bit it mentions that a good reason to suggest a photo for DQ is
"- The photo consists of a composite of multiple images that couldn't have been created in-camera (ie multiple exposures in-camera are legal). "
The X-ray image used an image on a screen, Would I for instance be able to take a photo and place that photo with-in another photo ?(not just take a photo of the other photo but to have it be an element in the photo.)
if your camera supports uncompressed quality (RAW), use it. then use Photoshop RAW plugin for processing. Better than multi exposure.
But that would not be legal for DPC, your double exposure needs to be inside the camera.
There is a way to use RAW and photoshop, to simulate the results of staking bracketed exposures to get an increased dynamic range that is legal in Advanced. kirbic has described it better than I can in another thread.
However increased dynamic range is not the only use of double exposure. Sometimes you may want to combine two exposures that are not the same subject-wise. Some Fujifilm models (and perhaps others) can combine two exposures in-camera and output them as one image file. That would be legal in both Basic and Advanced, but the voters may not treat it too kindly.
There are creative ways to do multi-exposure in-camera with cams that do not directly support it. One way is to darken a room, open the shutter, and fire the flash manually multiple times, or use combination of continuous and flash light sources with a single long shutter opening.
Another related technique, supported by some Canon flashes, is "strobing" the flash. The 580EX, for instance, will fire a low-power pulse as fast as 10 Hz (10 flashes per second).
