If shooting at f/22, is a fast 1.8 lens still considered fast?

Started Apr 17, 2011 | Discussions thread
edwardaneal
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In reply to edwardaneal, Apr 22, 2011

please go read this before you answer my questions - thanks

http://nikonrumors.com/2011/03/28/auto-focus-accuracy-a-scientific-cross-brand-analysis-guest-post.aspx

they did scientific, cross brand, tests of AF accuracy in a controled environment with lenses of different apertures and different makes and they tested all camera brands and did a special comparison of Nikon and Canon

they concluded that Nikon had the advantage but they also concluded that lens brand and aerture made a bigger difference than camera brand

this is from the conclusion

" Auto-focus is the most accurate for intermediate lenses (aperture between 2.8 and 4) . Brighter lenses’ shallow depth of field requires a fine calibration of the camera auto-focus system which didn’t seem to be made in factory.

The difference between Canon and Nikon with > =f/2 lenses is not significant.

Data used in this article come from a controlled environment (studio and target). An error of 4% seems the norm in these conditions, with 6-8% for very bright lens (f/1.4). Results suggests that focus-error may increase with any light loss. "

if having a faster aperture than f/5.6 has no effect on AF accuracy could you please explain how their test results on both Nikon and Canon showed that AF accuracy results were best using apertures between f/2.8 & f/4?

Also you keep saying that only Canon has bodies that can take advantage of faster apertures yet in this test which included top of the line bodies from both Nikon and Canon Nikon did better. If Canon had some special sensors that nikon does not have why do you think Nikon did better?

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My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
SB800, SB600 and other misc lighting equipment

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

 edwardaneal's gear list:edwardaneal's gear list
Sony Alpha NEX-7 Sigma 60mm F2.8 DN | Art Carl Zeiss Touit 1.8/32
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