Sigma 50mm Art acting weird...

[andrewdoeshair]

I hope I'm posting this in the correct place. Sorry to make the story so long....

I've been using the Sigma 50mm F1.4 art series lens on my 5Diii for about a year now, but about 3 months ago I bought a second, cheaper setup (Sigma 30mm F1.4 Art and a Canon SL1) so that I could have a second camera for when I shoot video. After fiddling with the cheaper setup for a few days in the salon I realized that for my intended purposes (instagram) I could get an image that was just as useful but at 1/4 the price and weight. I started dragging the SL1 with me everywhere and I let the 5Diii collect dust. Two weeks ago I had a slightly more important shoot, I was working with a really great model, so of course I had to use my "more professional" setup. Only it felt kind of weird...

That night I thought it was feeling weird because I had gotten used to the SL1, but then the next day it was still acting weird. I thought maybe I was having an off day, or that I wasn't being patient enough to get the shot right. The third day back on the 5Diii I was very deliberate and careful to get the shots, and that's when the weird symptoms started showing.

First, it was front focusing. I know that a lot of people complain of that with these lenses, but this one never had any issues. I didn't know it could do that out of the blue, become poorly adjusted, I thought it had to come from the factory poorly adjusted.

Second, I noticed that the bokeh was unusual. Lines were doubling and distorting oddly. It didn't have the same creamy look it usually did, it looked more like a psychedelic trip.

Third symptom was uneven DOF. I don't know exactly what it's doing, it's kind of sporadic, but it's like more shallow than it should be or shifted to a weird angle.

I'm not totally positive, but I feel like everything was exposing a little bit darker than it used to, too. I normally shoot a haircut at ISO 100, F2.0 to 2.8 and shutter between 1/60 and 1/100 but since the weirdness I've been having to bump my ISO as high as 400.

Finally, there is very little contrast. Everything is light and hazy.

I tried calibrating it with the USB dock and it seemed fine right away, but then the weirdness came back. Sometimes it does all these things more than other times, sometimes it's perfectly fine again. I have no idea what it could be. Aperture blades are moving perfectly (as far as when I'm watching them. Maybe they're just on good behavior while I'm checking). Other lenses work perfectly on the body, and as I'm writing this I'm realizing I haven't tried the 50mm on another body yet.

This is what it's doing. This unedited image was about the worst of it, I wanted to throw the lens away when I got this onto my computer. I focused with the center point on the center of his sunglass lens nearest us. This was at F2.2

Anyone ever had this happen? Got any suggestions?

 

[robbins.photo]

Step one, figure out if the problem is the camera body, or the lens. Put the lens on your second body and test, put your other lens on the 5d and see how it performs.

If the lens performs badly on both bodies, most likely the problem is with the lens. If the lens performs fine on the SL1 and the 5d has problems with the other lens, then most likely the problem is with your 5D somewhere.

When you do your test shots, don't use a moving target. Use something stationary. A fast shutter speed or a tripod to eliminate camera shake as a variable. Unfortunately without EXIF data it's not really possible to tell what's going on with the sample image, if it were shot at a low enough shutter speed that might be part of the problem.

So I'd recommend a stationary target, I've found things with lettering to be very useful for these types of tests, so a street sign or a house number makes a great field test.

 

[andrewdoeshair]

I fixed it. What I did was put the caps on both ends, put the hood on backward, slipped it into the padded case, stored the whole thing in the back of a cabinet, then I bought a Canon EF 24-70mm F2.8L... I got the old one, not the MKii, but this clean copy was $800 at a local camera store and the MKii didn't seem like it would have been worth twice as much. I've owned four Sigma art lenses since I sold my EF 24-105mm F4L and now I realize I shouldn't have judged L lenses based on their cheapest model...

I'll have another look at this busted 50mm when the 24-70 stops being exciting.

 

[PaulWog]

I fixed it. What I did was put the caps on both ends, put the hood on backward, slipped it into the padded case, stored the whole thing in the back of a cabinet, then I bought a Canon EF 24-70mm F2.8L... I got the old one, not the MKii, but this clean copy was $800 at a local camera store and the MKii didn't seem like it would have been worth twice as much. I've owned four Sigma art lenses since I sold my EF 24-105mm F4L and now I realize I shouldn't have judged L lenses based on their cheapest model...

I'll have another look at this busted 50mm when the 24-70 stops being exciting.

Everything has a chance of breaking. I've found a minor defect in about 1 in 4 lenses I've owned. I've found extremely bad defects in about 1 in 5 lenses I've owned. With that said, I haven't owned Canon, just Nikon Tamron and Sigma.

The picture looks like there's an element that is out of alignment.

 

[beagle100]

I fixed it. What I did was put the caps on both ends, put the hood on backward, slipped it into the padded case, stored the whole thing in the back of a cabinet, then I bought a Canon EF 24-70mm F2.8L... I got the old one, not the MKii, but this clean copy was $800 at a local camera store and the MKii didn't seem like it would have been worth twice as much. I've owned four Sigma art lenses since I sold my EF 24-105mm F4L and now I realize I shouldn't have judged L lenses based on their cheapest model...

I'll have another look at this busted 50mm when the 24-70 stops being exciting.

OK but it looks like the old Sigma needs repair and may not be worth it