So yeah - the Sigma 50mm kinda sucks

I think it just needs some calibration...

It may not be your lenses' fault. it could be your camera that needs to be calibrate to the Sigma lens.

I think it is too soft. The functional performance of Sigma 50 is way better than that.
Maybe you should try to go to Canon instead of Sigma and see if they can help you. I think others are not being helpful when the actual problem does exist and they tell you to ignore it.

Although the nifty fifty is known to be sharp, Sigma should be at least as sharp. Sigma should be sharper than 50L. For those who actually believe 50L is sharper, 50L isn't as sharp as other L's. People buy it for its bokeh. Sigma can't create what 50L can in blur quality.

sbattey wrote in post #13149225
my eyes can barely focus reliably on a number on a ruler

Send them in for recalibration.

"FOCUS WAS ON THE RED 16 MARK."

Unfortunately you see this go wrong all the time... that's not necessarily how focus points work. Rather than a single point, the focus "cross" probably spans all the way down to 15 and 17.
As much as I like to rip on Sigma's terrible calibration and QC, in this case it might not even be a lens issue.

Try shooting a subject parallel to your sensor, such as a matchstick box (or anything flat and small with a barcode), and put a few next to eachother front to back from left to right in incremental steps of about 3mm. That'll give you a much more realistic test than yet another tilted plane test.
The tilted plane test simply doesn't work like that.

One thing you should note is that sigma 50/1.4 is a bit soft at close distance (like less than 1 meter). It sharpens up quickly at normal portrait distance (1m-3m).

Also, as others have mentioned, your testing method is flawed.

mine had horrible front/back focusing issues and I got it calibrated. Now it front focuses at times but is much better overall. I think a little microadjusting via my camera will yield the results that I want. I may just send in the lens with my camera so its matched perfect. The calibration really does help this lens and its only 10 bucks to ship it.

Worst test subject ever. I was once like you, shooting random objects looking for errors in my lenses. I found plenty. But when shooting in the real world a misfocus might occur once out of 25 with my Sigma 30, and that is usually my error. Enjoy shooting rulers the rest of your life instead of enjoying the lens.

sbattey wrote in post #13149225
Worst subject ever, my eyes can barely focus reliably on a number on a ruler, how do you expect your camera to?

The point is...his camera can with 1.8 Canon and cannot with Sigma Sorry for your eyes

Ferrari_Alex wrote in post #13149837
The point is...his camera can with 1.8 Canon and cannot with Sigma Sorry for your eyes

How can we be sure that the Canon actually isn't misfocusing, and the Sigma is dead on?

To test sharpness, focus manually with Live View on 10x enlargement. To test auto-focus, use a proper chart, good, consistent lighting, and be sure to de-focus the lens to the same point each time between shots (to make sure that lens 'backlash' is not a variable). In any event, always use a tripod, remote release, mirror lock-up, and manual exposure.

is this sigma 50 1.4? cos i know that lens has some crazy focus issues....

Ebwly wrote in post #13149987
is this sigma 50 1.4? cos i know that lens has some crazy focus issues....

I know some people post in threads without reading the body of the post, but did you even read the title?

Sirrith wrote in post #13150169
I know some people post in threads without reading the body of the post, but did you even read the title?

"So yeah - the Sigma 50mm kinda sucks'

I'm sorry...did you read more into that than I did? I must have missed that invisible part where it said which sigma 50mm it was.

How is it that people think a tape measure test is somehow less accurate than "real world"? DOF is DOF and it doesn't matter what the subject is.

I bought a 30mm 1.4 at adorama. It was front focusing off by 2 inches at 24 inches. This is bad. In the "real world" this means the eyes are clearly out of focus at a shallow DOF but the tip of the nose might be in focus. I sent it back, got another. Bad as well. Worse in fact. So I contacted adorama and they went out of their way to test and find a good one for me before they shipped it. The third was is fantastic and I'm glad I went through the trouble. This appears to be a common problem with Sigma. I would either see if you could get a replacement or send it to sigma for calibration. If you do that they will say that they prefer you to send the camera so they can "calibrate it to your body" but what you are dealing with here is likely not a camera/lens mismatch. It's a lens that is out of spec right off the production line.

I have a guess that they don't calibrate these lenses before they leave. They just make them and ship. The few that people both with can be handled through warranty. Alternatively it may be that they are sensitive to jarring and many get screwed up in transport. That I won't be able to tell unless I have an accident so I don't plan to test it. Whatever the case, when you get a good one, they are fantastic lenses, but getting a good one can be a PITA..

Ebwly wrote in post #13150209
"So yeah - the Sigma 50mm kinda sucks'

I'm sorry...did you read more into that than I did? I must have missed that invisible part where it said which sigma 50mm it was.

I'd have thought spending time on this forum would let you draw the conclusion that when someone talks about a problem with a sigma 50mm, its going to be the 1.4, further, if you then went on to read the OP's first post, you'll see he shoots his sigma 50mm at 1.8.

Another thread like this?