Sky flat level @ Canon 350D

[FunkyKoval35]

Hi. I have a question. How to make proper sky flat? I know that I should take them at the post-sunset or pre-sunrise sky, but what level of the flats should be?

Adam 

[VigdisVZ]

As I've understood it, you reduce exposure time until the histogram is about 1/3 to 1/2 of the way from the left. Worked reasonably well for me two days ago when having the histogram peak about halfway. I used a white shirt stretched over the opening and a diffuse work lamp instead of pointing straight up at the sky.

[FunkyKoval35]

Thank you for advice. I will try it.

[steppenwolf]

A good method of capturing the correct exposure for your flats with a DSLR camera is to set it to 'Av' mode and let the camera determine the exposure length.