Help please with Canon body and Sigma 300 f2.8 HSM auto focus...

Started Nov 17, 2010 | Discussions thread
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Olgierd
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Help please with Canon body and Sigma 300 f2.8 HSM auto focus...
Nov 17, 2010

Hi,

I have bought used Sigma 300mm f2.8 HSM and have really lousy results with auto focus performance on my two Canon bodies (7d and 5d2).

I just have finished shooting AF target chart (camera on tripod, triggered from my netbook). Used DPP, shot JPG Large in Manual exposure (1/200; F2.8; ISO 100 with studio strobe triggered remotely). Test chart taped to the wall, camera set on tripod, roughly 45 degree angle to center of the test chart, shoting center vertical line on the test chart.

First I have tried 7D - One Shot AF, center AF point spot. Had to dial +13 micro adjustment to get consistent result. Tried other AF modes with same +13MA. All of them were OK accept center with assist (4 adjacent AF points). Every shot I tried in this setting was with heavy front focus.

Next I tried in ServoAI. All shots turned out to have heavy back focus. I dial +20 micro adjustment and even then could not achieve correct focus.

Later I tried my 5D2 using same setup and only center AF point. First in One Shot AF

with center AF point only. Had to dial positive MA (+10). Switched to servo AF with center AF point only and same problem. Heavy back focus - even with +20MA.

Has anyone experienced similar problems with such camera lens combination? Or perhaps someone can advise me where should I go with this problem. Should I call Canon or Sigma?

Thank you.
Olgierd

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Olgierd

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