Anyone Else With Sigma 50A Focusing Issues?

Just got my long-awaited Sigma 50mm f/1.4 ART lens, and discovered that it's backfocusing at close distances, but pretty sharp at 10ft+. I've returned 6 Sigma 50mm (non-ART) lenses at some point or another during the last 4 years.

What's your experience with the focusing of Siggy 50A ?

I have the non-art and no issues but you should get the Sigma dock, it should fix the issues

I saw one person say it worked better on the 5D3 if set to only use the cross-type AF points. Can you give that a try?

If it's completely consistent in its behaviour, then the dock should take care of it because you can make corrections that apply to 4 different distance ranges.

However, my advice to any Sigma Art users who haven't already done so, is to get a chart and test focusing consistency at 0.5, 1.0 and 1.5m, in both daylight AND tungsten lighting.

I had the 35A for a while, but it was completely inconsistent and unreliable in tungsten light, at the distances above.

Note - when testing focus consistency you have to defocus before every shot; when testing my sigma I thought it better to defocus in different directions each time, and after a few shots I thought I'd established that if I defocused clockwise the camera front-focused, and if I defocused anti-clockwise the camera back-focused, but after about 20 repetitions it was clearly just random. The 'pattern' I'd seen earlier must just have been random luck. Anyway.. shoot at least 20 frames at each distance to establish consistency.

I could never get mine to focus consistent even with the dock...I returned mine

I had to make an MFA adjustment of over +10 with mine when I first got it and have been very pleased since.

No problems with my 50A on a 6D... though I did drop it and have to have it repaired only a few weeks after purchasing it so I wonder if they zapped anything that MAY have been wrong (but didn't notice anything bad the first time around)

I'm afraid to mess with the doc, as I got it new from Adorama. I'd rather exchange it for (fingers crossed) a good copy. I've had a Sigma 35A, which was excellent and did not require any MA. But for some reason, with 50mm Sigmas, my luck has not been as good.

LonelyBoy wrote in post #17452072
I saw one person say it worked better on the 5D3 if set to only use the cross-type AF points. Can you give that a try?

That's what I've tried. I always try to shoot with 1pt AF. Especially with fast lenses like f/1.2 or f/1.4.

I have no problem with my 50A. Tack sharp. I did however change one " calibration number" to +1. everything else is at 0 using the sigma dock. I probably move one number to 1 just to give the dock a sense of purpose...haha. My dock was invaluable however with my 35A. Once honed in, my 35A is also tack sharp through all distances.

you're batting .500. with sigma lenses that's an excellent average