07-20-2010, 08:36 AM
Hi Lars,
[quote name='larsrc' date='20 July 2010 - 09:42 AM' timestamp='1279611766' post='1143']
Surely what it looks like depends on what the maximum aperture of the lens is? To be extreme, I doubt an f/1.2 shows the same DOF as an f/5.6, and I'm pretty sure an f/8 (e.g. mirror lens) will not look like an f/5.6. Wouldn't it be more correct to say that it looks like about two stops slower (assuming you were talking about f/2.8 lenses?
-Lars
[/quote]
No, it actually does, and I did see the calculations for this a few times, somewhere. Unfortunately I don't hav eth elinks for thsi anymore, so I can't show those to you. It went a little beyond me anyway, the calculations that is <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. It may be a little less with FF than with APS-C, but it is roughly F/5.6 with the standard focusing screens. If this wasn't the case, it would make no sense to have focusing screens with a much, much finer matting structure for use with large aperture lenses.
In a way you can compare this with film/analog. The emulsion thickness of film, 0.2 mm, provides more DoF than digital does, with a sensor thickness of 0 mm. This is a similar effect, not entirely, but similar anyway.
Kind regards, Wim
[quote name='larsrc' date='20 July 2010 - 09:42 AM' timestamp='1279611766' post='1143']
Surely what it looks like depends on what the maximum aperture of the lens is? To be extreme, I doubt an f/1.2 shows the same DOF as an f/5.6, and I'm pretty sure an f/8 (e.g. mirror lens) will not look like an f/5.6. Wouldn't it be more correct to say that it looks like about two stops slower (assuming you were talking about f/2.8 lenses?
-Lars
[/quote]
No, it actually does, and I did see the calculations for this a few times, somewhere. Unfortunately I don't hav eth elinks for thsi anymore, so I can't show those to you. It went a little beyond me anyway, the calculations that is <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. It may be a little less with FF than with APS-C, but it is roughly F/5.6 with the standard focusing screens. If this wasn't the case, it would make no sense to have focusing screens with a much, much finer matting structure for use with large aperture lenses.In a way you can compare this with film/analog. The emulsion thickness of film, 0.2 mm, provides more DoF than digital does, with a sensor thickness of 0 mm. This is a similar effect, not entirely, but similar anyway.
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
