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next PZ lens test report: Sigma AF 50mm f/1.4 EX HSM DG (full format)
#12
[quote name='Klaus' date='03 June 2010 - 11:02 PM' timestamp='1275598966' post='157']

"Residual spherical aberrations" - the lens suffers from focus shifts when stopping down.

The focus information is obtained at max. aperture so it's slightly off at other settings. At close focus distances this is a relevant problem.



RSAs are not so uncommon in this class.

[/quote]

No, it generally even is one of the reasons why bokeh with these lenses is better. Some of it is deliberately left uncorrected, and sometimes I think even deliberately introduced, in a more or less controlled way, as far as that is possible.



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 ....
  


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next PZ lens test report: Sigma AF 50mm f/1.4 EX HSM DG (full format) - by wim - 06-03-2010, 09:06 PM

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