50MM 1.4 Focus issue

theurbanclown

theurbanclown

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Ben
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Firstly, this is not user error. All photos were taken on my 5D MKIII, set up on a tripod and all using the centre focus point at 1.4

When I'm shooting close up (photo #1) there doesn't seem to be an issue - I'm pretty happy with the focus and sharpness, but when the subject is a little further away (photos #2 and #3) the lens seems to front focus. I used to think this was possibly my 550D, but now testing it on the new body it's still an issue. It's definitely not the body as my 85mm 1.8 and 35mm 1.4 L have no problems at all, regardless of subject distance.

Good enough reason to take it back? It's under warranty until tomorrow!


#1 Focus was on coloured buttons. Seems fine. Subject around 0.5m away

focus-1.jpg



#2 Focus on the camera. Focus seems to be towards the front of the photo. Subject around 5m away.

focus-2.jpg


#3 Focus on the wicker basket. Focus seems to be on the sofa, so some way off. Subject around 4m away.

focus-3.jpg
 
Yes. Though I'm sure Sigma could recalibrate it, and it's a really nice lens.
 
I'd say take it outside and shoot something normal, in house testing I find is unreliable to the point you literally start pulling your hair out, to me it looks like it focusing on the most contrasty part of the image which is fairly normal, like the picture frame being black against white, sofa being dark grey against white, I think (I am no expert, far from it, so this is just free advice on my take on it) stick it in liveview and it should focus fine on what you point it at, it's most like my 35mm, it can be a right pain to focus bang on indoors
 
theurbanclown said:
Thanks for the reassurance. It's not a Sigma though, it's Canon.

Off to Calumet in a bit to see what they can do.
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LOL Not sure where I got Sigma from :thinking: :D

Unless you're using auto AF point select instead of centre point, I would say that's far enough out to be conclusive.
 
HoppyUK said:
Unless you're using auto AF point select instead of centre point, I would say that's far enough out to be conclusive.
Click to expand...

Also, it is just possible that your target lacks anything for the camera to really lock on to. When pushing things to the edge of what AF can do I think it's best to give it a helping hand if at all possible by aiming at something that gives it the best possible chance of achieving a lock.

The remote control (although it doesn't look too bad) and the low contrast sloping picture could possible task the best AF system but the basket should be a better target depending on where exactly the AF point was.
 
Ivan S said:
I'd say take it outside and shoot something normal, in house testing I find is unreliable to the point you literally start pulling your hair out, to me it looks like it focusing on the most contrasty part of the image which is fairly normal, like the picture frame being black against white, sofa being dark grey against white, I think (I am no expert, far from it, so this is just free advice on my take on it) stick it in liveview and it should focus fine on what you point it at, it's most like my 35mm, it can be a right pain to focus bang on indoors
Click to expand...

It's gone off to get re-calibrated now. I agree that outdoors would have been best, but I stacked the 50mm up against my 85mm 1.8 in the same conditions and that had absolutely no issues with focus on the same items.

For example:

focus-4-1.jpg


HoppyUK said:
LOL Not sure where I got Sigma from :thinking: :D

Unless you're using auto AF point select instead of centre point, I would say that's far enough out to be conclusive.
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I think it's probably because I didn't specifically say Canon, and Sigma also do a 50mm 1.4 :)

I was using centre point.

woof woof said:
Also, it is just possible that your target lacks anything for the camera to really lock on to. When pushing things to the edge of what AF can do I think it's best to give it a helping hand if at all possible by aiming at something that gives it the best possible chance of achieving a lock.

The remote control (although it doesn't look too bad) and the low contrast sloping picture could possible task the best AF system but the basket should be a better target depending on where exactly the AF point was.
Click to expand...

I focused exactly on the wicker basket. For that one it is possible that the backlighting caused an issue, but still, it's gone back and I should have it back in a couple of weeks.
 
Ben,

Let us know when you receive it, please.

I also have those lenses, but on a 5Dc (both calibrated). The 85mm AF is more accurate.
My 50mm AF sometimes misses the subject (expecially when it is more then 5m further) and front focus a bit.
My my body is only a 5Dc... :\
 
I know you can tune miro-adjustment for different focal lengths on the 5d iii I wonder if there is an option for focus distance? this would help the op a lot and satisfy my curiosity if anyone knows

edit: i've just realised how silly that sounds :bonk:
 
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To test whether it is the lens or body at fault, or if the two just don't like each other, try shooting in live view. If live views contrast detect nails focus, the lens is absolutely fine. If it shows similar issues as above, the lens most likely requires calibration. My 50 1.4 didn't like my 7D but was fine with other bodies. My 7D was fine with other lenses but the two just didn't get on when shooting through the viewfinder. It could be a 50+crop thing.
 
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Right got the lens back and hats off to Canon, they've pretty much replaced everything. It's basically brand new.

Here's a list of things they've done;

Replaced focusing USM assembly
Replaced collars and screws
Readjusted auto-focus
General external cleaned
General external barrels and focus buttons cleaned

The lens is much better now. The same sample shots have come out much sharper.
 
theurbanclown said:
Right got the lens back and hats off to Canon, they've pretty much replaced everything. It's basically brand new.

Here's a list of things they've done;

Replaced focusing USM assembly
Replaced collars and screws
Readjusted auto-focus
General external cleaned
General external barrels and focus buttons cleaned

The lens is much better now. The same sample shots have come out much sharper.
Click to expand...

:thumbs: Thanks for feedback, always interesting :)
 
Glad you got good service from them. Its always a 50/50 % chance of getting good service from a big old company.
 
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