Why picture quality decreasing with very big apperture? [closed]

Question

Possible Duplicates:
What is a “diffraction limit”?
Why are my photos taken at f/11 less sharp than those taken at a wider aperture?

I have made 3 landscape pictures with f/12, f/22 and f/32. Shutter speed and ISO are almost same, but last one has a lot of blur and is very pale. Why this happen? My purpose was to get maximal DOF.

Details: Nikon d5100, 18-55 kit

Asked by yura

Answer

Without wishing to get into detail - the short answer to your question is diffraction. This happens at smaller apertures, usually when you get above f/16 to f/22 etc, and the extent to which it occurs depends on the optical quality of the lens used. In your case, the 18-55mm kit lens which is a mass-produced cheap kit lens will show this problem moreso than say a fixed focal length prime lens.

You can achieve good depth of field with a more modest aperture such as f/14. There is rarely if ever good cause to go all the way up to f/22.

Answered by Mike

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