July 30, 2014, 07:37:55 PM

Author Topic: AF Performance 70D variying from lens to lens - Anybody else this problem?  (Read 371 times)

xps

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I recognized that my 70D´s AF performance and accuracy varies from lens to lens.
The German "Color Foto" magazine compared the AF perfomrance and accuracy between some Cams (SLR, MLils,...) and between some lenses. There the 70D was no winner.... It perfomred best with the Sigma 18-35, worst with the 50mm Macro... (Lesser than half of all shots were sharp. NEX-7´s shots were over 90% sharp...
Ok. I read the test and was a little bit disappointed. I see thath some lenses perform better, some worser on the 70D. Noteable: mirorless Cams are most superior to the SLR (in this price class)

My question: I´d like to know, why my 70D´s AF performance varies so much, using 3 different 70-200 2.8L lenses when I shoot moving objects? I rented 2 from my clubfriends, one I own by myself. Mine was fast and mostly sharp, one was better (more sharp pictures), one noteably worser. But why?

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neuroanatomist

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AFMA?
EOS 1D X, EOS M, and lots of lenses
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xps

  • Canon 70D
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All lenses were adjusted by Canon CPS in spring this year. But only on their "home" cameras.
Ok, the sharpness will be influenced by that, but does AFMA influence the AF performance too?
Same situation, my lens got about 60% sharp, the worst of the three just about thirty? But why?


neuroanatomist

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What do you mean by 'AF performance'? 

Testing three copies of a lens on one body, AFMA can definitely make a difference - you'd need to calibrate each lens to that body.  Recent AFMA implementations on the 1D X and 5DIII are serial number aware, I think the 70D is also, meaning it would keep them straight.  But that's only with recent lenses.
EOS 1D X, EOS M, and lots of lenses
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xps

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Sorry, for beeing not precise. I shot on approaching racing cars, high speed AF and continuous shooting. The cars had about the same speed each pass. Afterwards counted how many pictures were sharp.
Ok, I will ask my friends, if I can do AFMA on their leneses at CPS.
Thanks for your information

neuroanatomist

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CPS doesn't do AFMA, they physically/electronically calibrate the lens itself (to a reference body).  AFMA is done by the user.
EOS 1D X, EOS M, and lots of lenses
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Valvebounce

  • 1D Mark IV
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Hi xps.
There is loads of information out there, if you do a little googling it will help you understand the differences between AFMA and CPS calibration. You really should AFMA each lens to your body if it supports it before trying to make comparisons to eliminate (or reduce) the effect of manufacturing tolerances and wear variation between samples.
For info on sample variation you could do worse than read Rogers blog at lens rentals!

Cheers Graham.

All lenses were adjusted by Canon CPS in spring this year. But only on their "home" cameras.
Ok, the sharpness will be influenced by that, but does AFMA influence the AF performance too?
Same situation, my lens got about 60% sharp, the worst of the three just about thirty? But why?
7D + Grip, 40D + Grip, 20D, EF-S 17-85 Kit lens, EF 70-200 f2.8 L IS II USM, EF 2x III, Sigma 150-500, Sigma 17-70 f2.8-4 C, 50mm f1.8, 550EX some Filters Remotes Macro tubes Tripod heads etc!
20D, BG-E2N, 17-85mm, 50mm are pre loved. :)
(300D Saved a holiday, E-FS 18-55 Cosine 100-300 retired)

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