thw2 wrote: n0b0 wrote:
Why do you sound like you\'re taking my post personally?
No I am not taking your post personally.
n0b0 wrote:
Have you ever done high magnification macro? The original poster said diffraction is a \"storm in a teacup\" so I showed him that it is a real problem for macro shooters who want to go above 1:1.
OK. But this thread is addressed to a large crowd. Very few people shoot super large magnification macro, let alone own the MPE-65. Besides, as has been correctly pointed out already, diffraction has nothing to do with pixel density. High pixel density merely goes to show what has already happened, without affecting diffraction in any way.
But I still find diffraction at f/5.6 quite strange. Diffraction can only happen when the size of the aperture is close to the wavelength of visible light (~ 500 nm).
You didn\'t see my earlier post.
In the macro world it is a real issue and the higher the magnification the smaller the aperture you need to use but you end up with the rule that you need to keep the effective aperture to around f/22 or less, and effective aperture is
f-stop*(M+1)
where M is the magnification. Shoot at 5x you\'ll need to stick to f/5.6 max otherwise the diffraction induced loss of detail is signifcant. f/16 at 5x is effectively f/96 and the loss of detail is enormous. At dpreview their was an extensive test of this showing indeed @ 5x above f/5.6 the results were apreciably worse, not just soft, but detail was being lost and by f/11 obliterated.
