Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: Samotano on August 17, 2008, 04:44:13 pm

Title: Multiple Exposures in Camera: what's going on?
Post by: Samotano on August 17, 2008, 04:44:13 pm
I was trying to familiarize myself with the Multiple Exposure mode on the Nikon D3, when I realized I really can't  understand what it does (at the pixel level, not in terms of the resulting effect).  

For those unfamiliar, according to the manual, the Nikon D3 allows to "record a series of two to ten exposures in a single photograph, [...] and produce results with colors noticeably better than photographs combined in an imaging application".

I tried to do some casual experimentation to see what happens when one uses 5 multiple exposures combined in camera compared to a single exposure for a static subject:
(http://farm4.static.flickr.com/3168/2771387423_83f6cfbcc9.jpg)
I took the resulting raw files (nef) and increased exposure in ACR in order to bring out the noise.  Clearly, there are benefits in terms of noise.  However, I don't understand what exactly happens to the raw files in camera.  Beside some super-secret proprietary algorithm, does anyone have any clue as to how each image is combined?  I wonder if this is equivalent to Guillermo Luijk's Zero Noise technique?