Sigma customer support

After spending some time with my lens (50mm 1.4) I came to the conclusion that it has some of the fabled focus issues. I called Sigma asking them how to send the lens in for calibration and the initial lady that answered the phone was either out to lunch mentally, or distracted by her cellular to the point that she wasn't even listening to my questions. She placed me on hold abruptly, and I was transferred to what I can only imagine was their Technical Support team. This was one of those, "Hi, can I help you?" me: "Uh...I ...uh, guess so?" him: "Well, what is it?" kind of conversations starting out... Though, this gent was only slightly better, but he actually went a bit into depth on some focus issues but basically was dismissive of the fact that I may in fact have a problem with my lens, which is WELL DOCUMENTED, I might add. He kind of leaned towards the fact that I didn't know what I was doing in a way. "Well, how far are you shooting from when this is an issue" kind of deal. I responded with, "Well it doesn't matter how far I am because the lens has a minimum focus distance. When I buy a lens, it should focus correctly from the minimal focus distance all the way out to infinity/wherever the lens stops grabbing focus. That's what I pay money for."

He invariably accepted that I send the body as well as the lens in for calibration, but when I asked him weather I need to send in a body as well as a lens when I upgrade to FF, he told me "of course, the lenses have to be calibrated to the body" in a very condescending way. He did offer up some information and told me the best way to calibrate it is to simply lay a yardstick on the floor, and shoot it from a height of around 2 meters about 2 meters away, straight on at 1.4. He told me to put something like a battery or anything, really that could be focused on on or near the ruler to dial in the focus. He claimed that this was the best way of dialing in the lens to the body.

It's great that he offered that advice, which I'll try before sending my gear in. But seriously, the condescending tone, the feeling that they just don't give a damn and the fact that the lens didn't come perfect out of box leads me to question weather this company is worth my dollars or time. I'll probably keep buying their stuff for at least another lens, because they do make good optics on the higher grade stuff. I just can't get over how lazy they sounded..

Thanks for listening to my rant. :crushed:

ouch, to have to send in the camera and lens for calibration,, and how long do they hold onto the equipment.. I would not be happy to mail in my D800 to some warehouse for this work.

If I'm not mistaken, I think all he's asking you to do is fine tune your lens. That's very different from having a lens focus issue. Fortunately, you have a camera that can fine tune lenses. But reading your description, it sounds like there's more going on than simply front and back focus issues. Do you believe that the issue is a front/back focus problem or ?

Well, what happens is when I calibrate it for f1.4, when I switch my aperture to anything else it seems to shift the focus a few mm front or back. So the calibration isn't completely across the stop range. Also, at night, it seems to lock on to whatever object is brightest, even when my chosen focal point is not the one that comes out being in focus in the picture. No other lens does this for me. It's the only one..

GRANTED: this seems to be erratic. Sometimes it will happen, sometimes not. But when it does happen, I know it's not user error. Well, most of the time I can be relatively sure it's not..

EDIT: THIS is essentially what he told me to do, but swap the chart for a ruler and the garage door with the floor:
http://photographylife.com/how-to-quickly-test-your-dslr-for-autofocus-issues

It's about a week turnaround from what I've read on the cybernet. Not bad, but I as well wouldn't want to ship my body out, no matter what. I just don't feel comfortable doing that.

First off, I've only dealt with Sigma support once and I have nothing but great things to say with how I was treated.

As for the rest of it, the idea of sending my camera in with a lens so they can calibrate it seems extreme, particularly prior to my doing the type of assessment he suggested, and that you've mirrored. One would have to assume that his recommendations are based on what the majority of people would have around the house (a ruler and a floor), but either would work for assessment purposes. Do it, and see what you've got on your hands. Document your findings and send them off to Sigma prior to sending in the lens (with or without the body). Obviously, if it's just a fine focus calibration issue then you should be able to do that as a part of this, and if it's not you'll have the proof that they need to know that there's a lens issue, and you probably won't need to send the body.

Well, the second issue is not coming from your lens, it's your body. Your camera will use an area surrounding your focus point in order to obtain a good focus and focus is dependent on contrast, which is very much lacking at night. This can be address by having a flashlight and illuminating the area you want the camera to focus on and then switching off your auto-focus once focus is obtained.

The first issue is much more critical. There should not be any change in focus from wide open to stopped down. If anything, the focus plane should increase and be more inclusive rather than less. I suspect your lens may suffer from "focus shift" and that's generally a function of the lens design and not something I believe they can fix.

The hall marks of Focus Shift is a lens that is sharper wide open than stopped down. And in fact will tend to back focus when stopped down. Here's a snipped on focus shift from Nisam Mansurov

Since cameras acquire focus with lenses at their maximum aperture (in this case f/1.8), stopping down the lens to f/4-f/5.6 will put your focused subject slightly out of focus, moving the focus plane back – result of focus shift. In addition, the area that appears sharp in the center will not distribute evenly across the frame – result of field curvature. This is generally not a huge problem for landscape photography (most of these issues are gone by f/8-f/11), but could definitely be problematic for other uses.


Focus shift explanation here

OK, so..let's just go ahead and beat this to death to see if we cant figure out what's going on.
I thank all who've replied willing to help. Hopefully that includes analyzing some pictures!

I started off shooting pictures in continuous mode of this cat next door who loves to wonder over. I shot at 1000/sec, f1.4, continuous mode, 3d tracking, burst. I know this isn't a very accurate way of deciphering this, but it is a problem nonetheless, however unrelated. Here are three shots that came out, first is the cat far away (you can see his tail clearly in focus instead of his head, which I focused on), second is the cat midway to me (everything is clearly OOF), and third is a perfect shot of the cat near to me, his head being completely in focus.





Then, I shot a pic of the ruler with a fag pack almost precisely on the 10" mark. Turned out well with a -4 compensation:



Thoughts?

In all three cat photos your focus point was set at the cats tail?

No, I kept it locked on the head..

With 3D tracking on it's going to go on movement in the focus field, regardless of where you might think you have it locked holding the shutter button down. Looks like it started on the tail, moved to a leg and locked on the collar in the final.

Have you checked the focus point in the camera display when you review the photo? If the red dot is on the cat's head then you have an issue. But if it's on a spot that's in focus then it's not an issue with anything but the focus mode you're using.

Just found this on 3D Focusing from the Nikon site...

"...the focus tracking system is a predictive system that uses special algorithms to forecast the position of the subject at the moment the image is captured. The prediction is based on a measurement of the subject's movement and speed.

Simple predictive tracking is very effective for pictures of a subject moving at constant speed toward the camera, but to provide maximum focusing performance for a subject that abruptly changes direction at high speed, or a subject with low contrast, moving randomly, the AF system must accumulate subject location data using multiple focus areas. The AF modules built into selected Nikon D-SLRs have as many as 51 focus areas that can detect vertical, horizontal and diagonal movement of the subject."

If the cat's moving at you and the camera predicted the speed of movement incorrectly then that would be responsible for the changes you're seeing. I suspect this would be most variable at the minimal dof you've got.

I rarely if ever use 3D focus tracking, even in shooting birds in flight (though that's the one time I consider it depending on the flight path). If you're analyzing a potential focus issue that's not the mode I'd be using.

I do realize that the DOF is razor thin at f1.4, don't get me wrong.. That probably has a lot to do with it. I'm willing to bet money that if I stopped down to say, f4 or even a little lower, that it would have been fine.. I don't think I'd ever realistically shoot say, racecars at f1.4 unless they were standing still and I was focusing on a very particular portion of the car..

Back on track however, it seems that if I shoot charts or very static objects on a tripod, the pictures come out great and in perfect focus. The second I pick up the camera, things seemingly go haywire for some reason. At f1.4, my shutter speed should negate any movement effects. I do keep my eye on that as well. So the question is still in a real-world scenario, what is happening to shift the focus away from the point that I want?

One very obvious flaw here is the focal point itself. Could it be that the focus point encompasses an area of the subject that is large enough to where it grabs the closest thing IN that focal point? Randomly? For instance, if I shoot a person's head at a few meters away and there is another person right behind the subject.. If the focal point area I've selected is larger than the subjects head is it possible that it will simply shift focus to the person directly behind the intended subject?

Oh, I forgot to mention that when sending your lens in to Sigma, apparently they HAVE to have a copy of your original receipt. Registering your lens on their site or through the mail has absolutely no effect on weather they will service it. Shi**y, no? I thought that was really ballsy..

As I asked previously, do you have the images on your card so you can check them in the camera and determine if the focal point shifts?

When you're operating in AF-A or AF-C mode then your point is dynamic, and it's going to shift. You want static? Put in in AF-S. The "real world scenario" you're painting tells me you're getting exactly what you're asking for. A constantly adapting focus target accompanied by a razor thin depth of field. AF-C is fine, just reduce the number of focus points, or at least 3D, and I suspect you'll see some change for the better. In certain scenarios AF-C can get real aggressive. Custom menu option a3 will allow you to turn focus lock on and off. How's it set on your camera? If it's off that may exacerbate your problem.

As for keeping the receipt, Nikon tells you to do it as well, and says that they may require you to provide it with warranty work. If you bought the lens from Amazon, B&H or another big retailer you may be able to view and reprint your receipt from there provided you did it using a user account on their site. I can go back a couple years with Amazon. To me it's ballsy to expect a manufacturer to service a product without one, particularly given how often things get sold "as new, with warranty cards" on eBay.

eurotrash said:

I do realize that the DOF is razor thin at f1.4, don't get me wrong.. That probably has a lot to do with it. I'm willing to bet money that if I stopped down to say, f4 or even a little lower, that it would have been fine.. I don't think I'd ever realistically shoot say, racecars at f1.4 unless they were standing still and I was focusing on a very particular portion of the car..

Back on track however, it seems that if I shoot charts or very static objects on a tripod, the pictures come out great and in perfect focus. The second I pick up the camera, things seemingly go haywire for some reason. At f1.4, my shutter speed should negate any movement effects. I do keep my eye on that as well. So the question is still in a real-world scenario, what is happening to shift the focus away from the point that I want?

One very obvious flaw here is the focal point itself. Could it be that the focus point encompasses an area of the subject that is large enough to where it grabs the closest thing IN that focal point? Randomly? For instance, if I shoot a person's head at a few meters away and there is another person right behind the subject.. If the focal point area I've selected is larger than the subjects head is it possible that it will simply shift focus to the person directly behind the intended subject?

Click to expand...

In keeping with your focus box theory, at f1.4 even just picking up the nose instead of the eye could make a noticeable difference! If it's working good on a tripod it must be the thin DoF, even the angle of the shot alone could throw it off.

I have a Nikon 50mm 1.8 and it has noticeable focus creep. I've ended up biasing it towards the wide end. When I got the D800, this issue combined with the reduced DOF of FX had me perplexed for over a week. I never knew about focus creep until this issue came up. It was weird because one minute I thought I had it dialled and the next it was gone again. The focus point is sooo critical as well. Miss it by a few mm and you're toast.

Well I was in the store again today picking up some things for a a few shoots I have lined up and I questioned the guy behind the counter who usually is quite knowlegable about things. I was able to replicate the issue in front of him. I told him to take a picture of me with my hand about a food in front of my face and focus on my palm. Sure enough, he focuses right in the middle of my palm at 1.4, and it was soft. What was not soft was the frame of my glasses about a foot behind the palm! So, he offered to send the lens in for me on my behalf. Naturally, I went with it. I knew I'd continue having issues with it if I didn't and wouldn't be happy until they at least looked at the lens. Hopefully they analyze it, and calibrate it correctly. He told me sometimes when they test the ones that come back, they cannot find anything wrong with them and they will send them back without even touching it! :ambivalence: I guess time will tell. I hope it manages to make it back before my trip to Gettysburg on the 16th..

STILL waiting for my lens to return from Sigma. It's only been a tick over two weeks, though it certainly feels like it's been a month or more.

I hope that it comes in this week. Will update when that happens.

Well, just got the call today and picked up the lens from the shop. Apparently, Sigma "calibrated the lens to D7k specifications", whatever the hell that means. anyway, so far it seems to be working 100%, but I do need more time with it. Today is a super nice amazing sunny day out so I plan on doing some more testing just to verify further that the lens is working optimally. Will update again.