Question about Canon EOS 400D / Rebel XTi Digital Camera

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Canon 400d constant backfocus

Focus is too long with 3 cm at 90cm , with any of autofocus points selected; setting that exclude false focus ( just a relatively small -but thick- cross, on gray background). Very bad for Canon EF 85mm f1.8 with depth of field of 0.5 cm in this situation. I suspect light having to travel diferent distances to CMOS / autofocus sensors. Same, but less noticeable with EFS 18-55mm.
How can i increase the lenght that light travel to autofocus sensors?

Thanks for your time!
 
Romania

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  • Anonymous Apr 13, 2008

    I have the same problem using EF Canon lenses L (the good ones) which did not give me problems with other Canon EOS cameras.

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Backfocus problems will be magnified when using wide aperture lens with shallow depth of field, nice lens btw. Camera's adjustments for manual and autofocus are inside mirror cage behind mirror, and you dont want to risk getting dust on sensor or damaging sensor. Qualified camera repair shop or sending to canon for adjustment would be my suggestion.

Posted on May 15, 2008

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