20D f2.8 focusing [in]accuracy

Started Nov 11, 2004 | Discussions thread
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Martin Eager
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20D f2.8 focusing [in]accuracy
Nov 11, 2004

I have a 20D and up until now have had no problems with focusing with Canon 17-40 f4L and Canon 28-135IS.

Today I received my new Canon 100mm f2.8 Macro and focus is awful. It front focuses terribly, both at macro range and especially at telephoto range (and yes I've tried switching between the different focus distance ranges, used centre point AF and made sure I'm not inside the minimum focusing distance etc).

This is my first f2.8 lens. The 20D is supposed to have increased focus accuracy with f2.8 lenses and better. Since my 20D focuses fine with non f2.8 lenses but ironically not with this f2.8 lens, is it possible that my 20D has a fault when it steps up to the more accurate focus sensors? Or is it more likely just a faulty lens?

The lens will be going back for exchange or refund anyway, but it's now got me worrying if I'll have problems with other f2.8 lenses.

Getting really tired of poor Canon quality control.

Martin
http://photos.runic.com

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