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next PZ lens test report: Sigma 50mm f/1.4 DG HSM | A ... full format

Statistics will never be complete and we will only know of a small percentage of lenses sold, that's the reality

The dud stats are derived from a couple thousand lenses from each manufacture (Roger @ LR), the sample is plenty large for calculations with alpha=0.05 and a tolerance of +/- 10%.



AF lenses have a comparatively small focus group - because AF motors work faster with a lower weight unit - and, and that's worse - the focus group has a low friction implementation. Or in other words - the focus group is rather 'loosely' mounted - because AF motors don't like friction either. An inferior centering compared to manual focus lenses is therefore inevitable. Add optical image stabilization on top ...

More than just that.  Take the modern lens with 16 elements or the vintage lens with 7 elements and wonder which is more complex to manufacture.  Factor in that the modern lens achieves radically higher levels of correction, and the effects of it not being assembled correctly become more readily apparent.  Lots of old lenses are 50mm f/x.x lenses, which are all planars.  Planar is very simple, and doesn't even have a "focusing group" (move the whole assembly) so it should come as no surprise that it is easy to center...


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next PZ lens test report: Sigma 50mm f/1.4 DG HSM | A ... full format - by Scythels - 06-25-2014, 01:53 PM

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