Originally posted by crayon:
... any idea if this 2nd exposure thing could be done in NeatImage? |
It is similar to making profiles for each of the different settings you use in NeatImage.
I believe the name of the technique is 'Black Frame Subtraction', and is one of the mainstays in certain fields (such as astrophotography).
It can be done in PS as well, just capture a few image with the shuttercap on for a few shutter-speeds that you use. Layer the black frame above an image with the same shutter-speed and set the blending mode to 'Difference'. Black in RGB is [0,0,0] so the difference between any pixel value and black will be the pixel value. The only areas of the Black Frame that are not black are the areas of noise, so the noise is reduced.
The down-side ( you knew there had to be one :D ) is there are two types of noise, constant and random. Constant noise is eliminated by this method, random noise is not likely to be affected much as it will randomly reduce, increase and have no effect on the random noise in the image. Random noise is handled effectively by stacking frames, btw.
Also, the biggest source of constant noise is heat. Because of this, making the black frame at the time the image is made (same environment) makes for better noise reduction. Going out and taking a bunch of shots and then making a black frame at home for a few that are especially noisy will likely help some, but not as much as making the black frame in the same environment the image was made in.
David |
