AF issues - Sigma 35mm f/1.4 and Nikon D800

DigitalRelish

DigitalRelish

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I've had my Sigma 35mm f/1.4 Art lens for a couple of months now and on occasion, I've noticed it focussing a foot or two in front of my subject. Over the past few days I noticed it a few more times and noticed it seemed to be when I was taking a photo of someone, holding the D800 in portrait and using one of the AF points on the right-hand edge to focus on the eyes.

After a bit of testing at home with a tripod and a contrasty subject it does seem to be that whenever I AF using the left or right-hand AF points the subject is out of focus. Without moving the camera, I've tried switching over to live view and positioning the AF rectangle over the subject and the result is a sharp image.

I can't replicate this issue with a Sigma 50mm f/1.4 and I can't replicate it with the 35mm on a D700. Seems like I only encounter the AF issue when I use a combination of D800, 35mm lens and one of the AF points on the left or right-hand edge.

Given the lens was purchase from DigitalRev, anyone any suggestions as to what I should do next?
 
its quite a well known issue i think , theres a few users on the Fm forums that have it anyway. Im sure the sigma dock worked for most of them in correcting it either that or send it to sigma(obviously at ur cost being from HK) or try DR
 
pmac said:
its quite a well known issue i think , theres a few users on the Fm forums that have it anyway. Im sure the sigma dock worked for most of them in correcting it either that or send it to sigma(obviously at ur cost being from HK) or try DR
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Thanks, I'll do some reading up over there.

Regarding the USB dock, I'm not sure it would be able to fix an issue with front focus only at the outer AF points would it? Wouldn't it just replicate the AF micro-adjust I could achieve in camera which I don't want to use because AF using the centre point is fine?
 
im not sure if its to do with adjusting the AF via the dock or by updating the firmware. might be worth checking the thread on the FM forum and asking.
Ive just bought a used 35 so hoping i have no issues with mine,my first d800 defenatly had the af issue but my E seems okay, bar with my nikon 85 front focusing at distance.
 
I've not had the issue and never seen anything about the issue that only affects the Sigma 35mm.

I know people had issues with left focus on the D800 at launch but that was with every lens I believe.
 
just received mine, and it also has the side AF issue.:rolleyes: middle is sharper than a sharp thing, right is close but the left is well out. going to order the dock and see if that sorts the issue, if not its off to sigma i guess.
Over all I'm very happy with it though,very sharp and focus seems very snappy.
 
I spoke with Sigma yesterday and they said it would have to go to them for calibration because the USB dock will only adjust the AF across the entire plane of focus. The issue we have is that the centre is fine and it's the outer regions which need adjusting.
 
DigitalRelish said:
I spoke with Sigma yesterday and they said it would have to go to them for calibration because the USB dock will only adjust the AF across the entire plane of focus. The issue we have is that the centre is fine and it's the outer regions which need adjusting.
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I sent my Canon mount Sigma 50-500mm OS for calibration a couple of weeks ago as it needed more than +10 correction to get a sharp picture and I thought I may as well get it sorted while it's still under warranty. Didn't hear anything from Sigma so phoned them and they have sent the ruddy thing off to Japan as they couldn't do it here in the UK ... 8 to 10 weeks waiting time. :arghh:
 
Mike.P said:
I sent my Canon mount Sigma 50-500mm OS for calibration a couple of weeks ago as it needed more than +10 correction to get a sharp picture and I thought I may as well get it sorted while it's still under warranty. Didn't hear anything from Sigma so phoned them and they have sent the ruddy thing off to Japan as they couldn't do it here in the UK ... 8 to 10 weeks waiting time. :arghh:
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Yikes! Fortunately, Sigma UK have got the necessary software to carry out the calibration on the 35mm so hopefully it shouldn't take too long to sort out once they're back in from Christmas.
 
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