Sigma 50mm 1.4 - Front Focus or Pixel Peeping?

Just got my lens in from Adorama yesterday and I am contemplating sending it in for calibration. What do you guys think?

Placed on tripod/ 45 degree angle/ constant light source (daylight bulb) / Aperture Priority

f/1.4

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​883200481/

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​883200569/

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​883200669/

Looks like front focus; but shooting at an angled target like that can easily screw up your AF system. Try with a better target, such as the Spyder LensCal target or TeamSpeed's Focus Genie chart.

This way, you are actually AF'ing on a specific plane (the vertical) and then have the angled bit to check where your focus hit. Shooting the angled target like you have here, the camera will focus "somewhere" within the depth of coverage of your AF spot. And since the AF spot functional area is slightly larger than the boxes you see in the viewfinder, this can lead to misdiagnosis of front or back focus issues.

8-10mm in front

Do the battery test....

Just realize no lens is perfect. The results above in no way will tell you what to expect in real life. They don't discount it either.

davidc502 wrote in post #13904554
Do the battery test....

Just realize no lens is perfect. The results above in no way will tell you what to expect in real life. They don't discount it either.

Understood.

I just want to know if this is the front focus that other Sigma owners are experiencing. As booja mentioned, it is 8-10mm in front. Is this acceptable?

Here is the battery test I did last night (f/1.4)..

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​879631469/

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​879632335/

i sent mine in... mine needed +10 or so

came back and it seemed the same... i was like ok they did nothing.

on my 7d that i had and on my 5dc its spot on. i guess its my 5d2. try another camera... if you or your buddies have another one. but knowing sigma its probably the lens. if thats the case send it in if you have warranty. they have a good warranty so why not use it. if you return it for another one you have a possibility of getting another bad one

Thanks booja (love your work btw!)

I wish I had another camera to try this out on. I have friend that has a 5d2 but he is out of town on an assignment.

I'm thinking about sending it to Sigma..but I'm also thinking about returning it and getting the Canon version...not really sure. I have a senior shoot next month and so I need to make a decision this week on what I'm going to do.

short_wave wrote in post #13905489
Understood.

I just want to know if this is the front focus that other Sigma owners are experiencing. As booja mentioned, it is 8-10mm in front. Is this acceptable?

Here is the battery test I did last night (f/1.4)..

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​879631469/

And I shot I took that earlier that evening (f/1.4)...

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​879632335/

Looks like front focus to me. I just purchased the same lens with the same problems. My post is here:

https://photography-on-the.net …/showthread.php​?t=1144894

My lens seems to be about the same as yours from a distance of ~2ft, but at ~4ft it seems to be pretty close to dead-on. I am curios to know if your lens reacts the same way.

sharrowm wrote in post #13905798
Looks like front focus to me. I just purchased the same lens with the same problems. My post is here:

https://photography-on-the.net …/showthread.php​?t=1144894

My lens seems to be about the same as yours from a distance of ~2ft, but at ~4ft it seems to be pretty close to dead-on. I am curios to know if your lens reacts the same way.

Yes!

At 2ft at f/1.4, the image is pretty much useless. Once I step back to about 4-6ft (still at f/1.4) the image looks great! This is what's throwing me off and forcing this over-analyzation.

I've checked out your thread and it seems like you are getting the same responses. Didn't want to hi-jack your thread! What did you end up doing?

short_wave wrote in post #13905833
Yes!

At 2ft at f/1.4, the image is pretty much useless. Once I step back to about 4-6ft (still at f/1.4) the image looks great! This is what's throwing me off and forcing this over-analyzation.

I've checked out your thread and it seems like you are getting the same responses. Didn't want to hi-jack your thread! What did you end up doing?

I'm still on the fence, but leaning towards keeping it as-is for a while and see how often the close-focus/front-focus issue comes into play with the way I shoot. I have 4 years to send it in under warranty if need be. But shots like this really make me want to forgive its AF issues (f1.4 at about 4ft focus on the "nose" ):

I know what you mean.

Truth be told I will more than likely stop down the lens but I do want the ability to use 1.4. I'm normally not that close when shooting 50mm just seems like I'm being limited.

So when you guys say "front focus", are you talking about the way the lens miss focuses on an area other than the focus target area? Not so much that its a soft lens, but rather the AF is not accurate and needs calibrated?

Jasper Ash wrote in post #13906384
So when you guys say "front focus", are you talking about the way the lens miss focuses on an area other than the focus target area? Not so much that its a soft lens, but rather the AF is not accurate and needs calibrated?

Exactly. The lens focuses in front of the subject. It has nothing to do with the sharpness of the lens. Just the accuracy of the af.

+1 with sharrowm

IMAGE LINK: http://www.flickr.com …/55639334@N03/6​879631469/

Ah I see. So what are your plans? Exchange it or send it to Sigma for service?