I haven't done much shooting since I got this gear, so I am doubting whether I am slipping as a photographer or something is going on with my camera or lens. Canon Mark III 6D Sigma Art 35mm 1.4 (recently calibrated) I'm going to post some pictures so you can see I'm really dealing with two issues. One is focus. It seems very shallow no matter what focusing mode I use. I calibrated for front-focusing and upon calibration it looks good now. In general, close up it focuses fairly well. But if I have more than 1 subject, it fails more than it succeeds. I've always had this issue with this lens, but I thought it was not calibrated. Now I calibrated it, and the issue remains. I double-checked focus points on these sample images, and all were correctly focused on subjects. The other issue is I see what I think is excessive luminance noise for these ISOs. Am I expecting too much of my camera? Or am I missing something? These were shot as light was fading. SOOC. Respective settings: 1. ISO 400 f/3.2 1/400 2. ISO 640 f/2.5 1/200 3. ISO 640 f/3.5 1/200 4. ISO 640 f/3.5 1/200
I am seeing noise that I would not expect at 400, did you post straight out of camera, or did you process them at all? Are you having focus issues with other lenses? It could be the lens or the camera. I would get a chart and do some lens focus testing with your art lens and another lens to determine if you have an issue and if its camera or lens related.
These are SOOC. Right, that noise must mean something is off right? Okay, so I only calibrated and tested the Art lens. I didn't even know there WAS a lens or camera malfunction that causes extra noise, so that's what's perplexed me. I was focused on fixing the focus issues. I haven't done a compare but I will do that next.
Ignore the noise comment, sort out your focus problem. You are definitely not focussed on the child because the background is much sharper. Take the camera off of green square auto and put it onto P mode, then set focus point to single centre point only. You will now know where the camera is focussing and will be able to see if it is getting it right.
I've narrowed it down to the issue only occurs at infinity focusing. So it must be the lens. I calibrated to infinity +20 with the dock, but it's STILL backfocusing on a lot of shots and not focusing at all on a large number of photos shot at infinity focal length. At shorter focal lengths, the lens is sharp. See these two pictures which were taken seconds apart in the same lighting with the same settings. The only difference was focal length. I've replicated this over and over.
I would contact sigma, I am not sure how long you have had the lens but the ART lenses are known for being high quality. Something may be off when focusing at infinity. Before you do however, I would note that the 35mm is the focal length, it doesn't change on this lens. Infinity is a focus distance, and none of the images should be focused to infinity that I saw. All of your subject are reasonably close to the camera, even if you were shooting and wanted one of the trees in the distance to be what was in focus, the camera in auto focus may select a focus that is not quite on infinity. Like you said, it seems you have an issue that is more prominent as the subjects get some distance from you, and you get towards infinity on the focus ring. (I'm assuming the shot of the girl girl is a crop in from a larger image, like the one above it, you probably don't have issues with closeups.)
do you have the red box overlays to see where the lens was focusing? also have you tried with servo mode? do you have any images of the 45% ruler test to see the amount of back focusing the lens is giving
