Sigma 50mm f1.4 fr.focus problems

Started May 21, 2009 | Discussions thread
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AJC Photography
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Sigma 50mm f1.4 fr.focus problems
May 21, 2009

OK, I have a dilemma:

I recently purchased what I saw would beautifully fill the last obvious 'hole' in my lens needs - a Sigma EX 50mm f1.4 (DG). I sent 1st one back before 7 days & got a replacement. This one also has front focus issues, but as others have found, the problem is worse the further away the subject is (even within say a 1m to 5m range).

P.S. - NO WAY will I be sending back both the lens AND my camera bodies to Sigma (as bodies are perfect sharp focus with Canon lenses).

1stly, background: (I'll try not to bore too much, but a little insight helps with understanding my frame of mind and modus operandi)

I shoot with 1D MkIIn bodies (so no micro adjust feature). However, when you know your bodies are 'correct' - then still one of the best single point AF accuracy there is.

My L zooms that I use for people shots are VERY sharp even wide open (28-70 L f2.8 & 80-200 L f2.8). I never doubt the wide open sharpness of the 28-70 (unlike my previously owned 24-105 L)

Again, happy with my Canon primes (35mm f2 & 85mm f1.8).

I shoot availbale light A LOT. When using off-camera speedlights too - I also try to keep to wide open apertures (I shoot in an environmental style - so like to blur background 'in camera'). My smaller coverage AF points on the 1D, allow for more accuracy than with my old 20D. I trust outer AF points far more. This helps me to NOT need to do 'centre AF, lock, recompose' ... which when shooting close up, wide open, can introduce focus shift.

Back to Sigma 50mm:

  • Who has had this problem and sent it back several times to get a 'good' copy ?

  • Who has simply (prefered?) to send 1st or 2nd 'bad' copy back to Sigma / Canon to be recalibrated ?

  • Who has used this or other lens with (inherent) problem (Canon 50mm L??) and has managed to find a CONSISTENT (repeatable) way of shooting someone and getting razor sharp focus EXACTLY where they want ? (which for me is usually on leading eye)

I want to love this lens as much as I loved my Sigma 30mm f1.4 on my old 20D. My copy had no focus problems btw. The 50mm is even better in terms of buttery bokeh, sharpness in the centre wide open and lack of CA or other distortions .... but obviously no good if it cannot focus where you want it to !

Ironically - I wouldn't even mind if it could be calibrated to work spot on ONLY upto about 5m or so (as it would nearly always be used as a low light / shallow DOF lens + not for landscapes or distant shots).

Anyone out there that has strong views on this 'problem' ? Who has a manual focus technique they use with this scenario ? Does anyone focus nearby but NOT on the (often low contrast) eye ?

Many thanks in advance
--

Good digital workflow is like washing my car - when I bother to do it's done meticulously, but sometimes I just end up cleaning the lights so I can see where I'm going

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