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Author Topic: Canon 50 f1.4 autofocus  (Read 1105 times)

stever

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Canon 50 f1.4 autofocus
« on: August 07, 2012, 08:38:08 pm »

After reviewing Roger's autofocus tests at lensrentals.com, i decided to re-test my 50 f1.4 which has never been much good wide open even after a couple of trips to Canon service (minor improvement).

Unfortunately i found that both PD and CD AF are unreliable at large apertures.  How can CD autofocus be unreliable even when i use magnification on a high contrast edge?  i tested 2 new copies that don't have this problem (and none of the lenses Roger tested had a CD AF problem) and will probably keep one of them after investing an excessive amount of time.

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Jim Pascoe

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Re: Canon 50 f1.4 autofocus
« Reply #1 on: August 10, 2012, 08:07:36 am »

Perhaps I am being a bit thick, but what is PD or CD autofocus?

Jim
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Bart_van_der_Wolf

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Re: Canon 50 f1.4 autofocus
« Reply #2 on: August 10, 2012, 08:45:21 am »

Perhaps I am being a bit thick, but what is PD or CD autofocus?

Hi Jim,

PD = Phase detect
CD = Contrast detect

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

Jim Pascoe

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Re: Canon 50 f1.4 autofocus
« Reply #3 on: August 10, 2012, 09:20:36 am »

Ah - of course, I was just being thick - must be the unseasonably warm summer weather we are having here in the Uk today!

Actually I found the Canon 50mm 1.4 to be a bit of a duff lens really - mine lies neglected at the back of the box.

Jim
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scooby70

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Re: Canon 50 f1.4 autofocus
« Reply #4 on: August 10, 2012, 10:23:12 pm »

I read a review some time ago and the gist was that the Canon 50mm f1.4 is pretty much incapable of giving consistant focus accuracy due to the type of focus system it uses. Too much play in it, or something. I can't give a link as this was some time ago... They provided a graph with plots of the focus accuracy of a number of lenses and they were all over the place. At smaller apertures the DoF could hide any focus accuracy issues but at wider apertures any misses will be much more obvious.

Sorry to be vague but that was the gist.

Personally I went for the Siggy 50mm f1.4 and I couldn't be happier.
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