Focusing, or Image Sharpness, using Canon stills and LCD screen.

[Scott Crawley]

If your black shading with a lens cap cover, isn't the value always the same? This value isn't stored within the Camera?

My understanding is that during a black calibration the camera is recording a sample of blackness and using that as a map of the noise to then program it out. That is written to camera and the sample is deleted I think. The amount of noise varies with operating conditions most notably the temperatures of the components, so no the value is not always the same.

[Barry Bishop]

My understanding is that during a black calibration the camera is recording a sample of blackness and using that as a map of the noise to then program it out. That is written to camera and the sample is deleted I think. The amount of noise varies with operating conditions most notably the temperatures of the components, so no the value is not always the same.

That's pretty fascinating if that is indeed true.

[Uli Plank]

That's the way it works.