05-19-2012, 10:23 PM
[quote name='popo' timestamp='1337460790' post='18342']
There is no single plane of focus, unless you have a perfectly corrected lens. Any single plane will not have all colours simultaneously in focus. The apparent plane of best focus will still allow colour aberrations to form on it, if the contrast is strong enough to make it visible.
I proposed a simple way to disprove this as a mechanism, and so far I have not yet seen a single sample that would do so. Find a shot where there is a clear plane of best focus, and purple fringing on objects clearly behind it that can not be explained by lateral CA.
[/quote]
LoCA are caused by spherical aberrations (hence the proper name of spherochromatism). They are therefore not visible within the DoF or in-focus zone.
Chromatic aberrations one will see in the focus area are lateral CAs. PF is visible in DoF and in OOF areas, and doesn't show the typical dual chromatic characteristics of chromatic aberrations proper.
Check the sample shot by Klaus taken with, e.g., the Canon 50L. Proper PF.
Kind regards, Wim
There is no single plane of focus, unless you have a perfectly corrected lens. Any single plane will not have all colours simultaneously in focus. The apparent plane of best focus will still allow colour aberrations to form on it, if the contrast is strong enough to make it visible.
I proposed a simple way to disprove this as a mechanism, and so far I have not yet seen a single sample that would do so. Find a shot where there is a clear plane of best focus, and purple fringing on objects clearly behind it that can not be explained by lateral CA.
[/quote]
LoCA are caused by spherical aberrations (hence the proper name of spherochromatism). They are therefore not visible within the DoF or in-focus zone.
Chromatic aberrations one will see in the focus area are lateral CAs. PF is visible in DoF and in OOF areas, and doesn't show the typical dual chromatic characteristics of chromatic aberrations proper.
Check the sample shot by Klaus taken with, e.g., the Canon 50L. Proper PF.
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 ....