next PZ lens test report: Canon EF-S 55-250mm f/4-5.6 IS STM - Printable Version +- Opticallimits (https://forum.opticallimits.com) +-- Forum: Forums (https://forum.opticallimits.com/forumdisplay.php?fid=4) +--- Forum: Canon EOS (https://forum.opticallimits.com/forumdisplay.php?fid=11) +--- Thread: next PZ lens test report: Canon EF-S 55-250mm f/4-5.6 IS STM (/showthread.php?tid=1439) Pages:
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next PZ lens test report: Canon EF-S 55-250mm f/4-5.6 IS STM - Brightcolours - 08-15-2014 Quote:Actually Sony does not underdesign lenses with the exception of the 16-50mm I think. Some of their lenses are just not good which doesn't help, of course. :-)CA correction is lossy too... You either do not correct them, and instead mask them (remove the colour edges), but then you keep the loss of contrast/sharpness due to CA anyway. Or, you shrink the "offending" R/G/B channel till all channels project the same size, but then you need to crop the image a bit too. At least you end up with better sharpness/contrast. next PZ lens test report: Canon EF-S 55-250mm f/4-5.6 IS STM - Klaus - 08-15-2014 I'd say that proper CA correction works on the R/G/B channels really. Honestly I do not see why this should shrink an image in a relevant scale. We are talking about max. 4px maybe - usually much less than that. next PZ lens test report: Canon EF-S 55-250mm f/4-5.6 IS STM - Brightcolours - 09-02-2014 Most camera manufacturers that offer CA "correction" do the colour artefact masking thing, not the correcting for real. |