Canon 50/1.2L or the Sigma 50/1.4A

I'm aware this question might set a few people off...

If budget was no limit, edge-sharpness unimportant and bokeh important, would you choose the Canon 50/1.2L or the Sigma 50/1.4A?

Opinions from people that have used/owned both are really helpful to me.

Also interested to know if the 50mm 1.2 has seen any design improvements/changes since it was first introduced.

I read of a <1m focus distance backfocusing problem. Not sure how accurate those reports are.

I'de probably go for the 50 1.2 again..... in fact, I'm picking up another 50mm F1.2 (FD L) and for the same amount, I can get the sigma Art if I wanted, I just dont want to deal with the weight.

Generally, when I deal with people lenses, I want good color, bokeh, and optics. I've never been disappointed by the 1.2, so I'm getting another one.

<1m, you get focus shift, but that's a fairly unrealistic distance to shoot, unless for pseudo macro, and that's usually stopped down a lot.

Charlie wrote in post #17203367
<1m, you get focus shift, but that's a fairly unrealistic distance to shoot, unless for pseudo macro, and that's usually stopped down a lot.

I've been enjoying head and shoulders portraits and find 50 is great for pairs, but they're definitely within a metre.

Focus shift is where AFing, then changing aperture results in a the plane of focus shifting (backward in this case)?

Do a search. This topic has been covered for a long time.

UKmitch86 wrote in post #17203429
I've been enjoying head and shoulders portraits and find 50 is great for pairs, but they're definitely within a metre.

Focus shift is where AFing, then changing aperture results in a the plane of focus shifting (backward in this case)?

that's correct. Issue is said to be noticeable from F1.4-2.8..... but in the years I have used it, I havent seen the issue in practice. Supposedly it exists

I had the same dilemma. Upgrade the Canon 1.4
I chose 1.2! I'm learning to handle the lens, but I think I made the correct choice.

Charlie wrote in post #17203474
that's correct. Issue is said to be noticeable from F1.4-2.8..... but in the years I have used it, I havent seen the issue in practice. Supposedly it exists

why on earth would someone change apertures after acquiring focus and not re-focus though?

to clarify, in case that seems hostile, I legitimately dont understand why anyone would do so and not re-focus, unless they are using a tripod, i guess... Regardless, I always refocus. Im constantly refocusing even if Im stationary.

I had the 50l forever (3 different copies). The af was horrendous on each of them but the only thing I found that was optically as good, if not better is the Zeiss Otus. A gigantic, manual focused $3500 bohemuth. That was until I picked up the sigma 50 art. Oh man, the image is just as good and the af actually locks on. I sold my 50l and haven't looked back

gnome chompski wrote in post #17204039
why on earth would someone change apertures after acquiring focus and not re-focus though?

Not sure if I understand you. It's not the photographer who changes aperture. It's the camera that always autofocuses at max aperture, then closes to the dialed in aperture on shutter release. Hence the misfocus. It is avoidable only by focusing manually while holding the aperture preview button (tricky on a 6D).

gnome chompski wrote in post #17204039
why on earth would someone change apertures after acquiring focus and not re-focus though?

to clarify, in case that seems hostile, I legitimately dont understand why anyone would do so and not re-focus, unless they are using a tripod, i guess... Regardless, I always refocus. Im constantly refocusing even if Im stationary.

You misunderstand the issue. Unless you're shooting at full aperture, the camera ALWAYS changes aperture after acquiring focus. That's an inherent part of AF.
Back focusing occurs because the focus plane shifts between the AF aperture (i.e., f/1.2) and the shooting aperture. This is a function of the 50L optics, and has nothing to do with whether the user re-focuses or not. A number of folks have described the phenomenon much better than I ever could. Google "50L focus shift".
Note that I say "phenomenon", not "problem". Many folks don't realize, or refuse to accept, that Canon made a conscious decision to make a lens with spherical aberration because in their view it was an acceptable compromise between image quality, bokeh, and physical dimensions. It was not a mistake or a flaw (at least in my opinion). Perhaps in this day of sophisticated lens design software, an f/1.2 lens could be made that equals all of the 50Ls good qualities while also eliminating SA. We'll see.

hang your cross wrote in post #17203472
Do a search. This topic has been covered for a long time.

There appears to be interest in this thread and I've got my questions. I could google forever and a day and not find the exact answers I want, so I'm having a discussion.

Charlie wrote in post #17203474
that's correct. Issue is said to be noticeable from F1.4-2.8..... but in the years I have used it, I havent seen the issue in practice. Supposedly it exists

Is your body able to do MFA? Have you done so?

codewizpt wrote in post #17203677
I had the same dilemma. Upgrade the Canon 1.4
I chose 1.2! I'm learning to handle the lens, but I think I made the correct choice.

I am swaying toward the 1.2 - the build, size, sealing, Canon AF all give me more confidence.

mdrtoys wrote in post #17204167
I had the 50l forever (3 different copies). The af was horrendous on each of them but the only thing I found that was optically as good, if not better is the Zeiss Otus. A gigantic, manual focused $3500 bohemuth. That was until I picked up the sigma 50 art. Oh man, the image is just as good and the af actually locks on. I sold my 50l and haven't looked back

What's horrendous about the AF? Do you own and use the dock with the Sigma? I've been burnt by AF issues on Sigma twice before - if I bought a 50 Art, why would it be different?

Bonpu wrote in post #17204174
Not sure if I understand you. It's not the photographer who changes aperture. It's the camera that always autofocuses at max aperture, then closes to the dialed in aperture on shutter release. Hence the misfocus. It is avoidable only by focusing manually while holding the aperture preview button (tricky on a 6D).

I'm glad you stated this, I'd not joined the dots re: auto aperture closing.

Snafoo wrote in post #17204365
You misunderstand the issue. Unless you're shooting at full aperture, the camera ALWAYS changes aperture after acquiring focus. That's an inherent part of AF.
Back focusing occurs because the focus plane shifts between the AF aperture (i.e., f/1.2) and the shooting aperture. This is a function of the 50L optics, and has nothing to do with whether the user re-focuses or not. A number of folks have described the phenomenon much better than I ever could. Google "50L focus shift".
Note that I say "phenomenon", not "problem". Many folks don't realize, or refuse to accept, that Canon made a conscious decision to make a lens with spherical aberration because in their view it was an acceptable compromise between image quality, bokeh, and physical dimensions. It was not a mistake or a flaw (at least in my opinion). Perhaps in this day of sophisticated lens design software, an f/1.2 lens could be made that equals all of the 50Ls good qualities while also eliminating SA. We'll see.

I guess I could wait forever, and not get the lens I'm sure we're all expecting Canon to produce. Do you simply get used to focused in front of a subject, assuming backfocus?

The 50L in a nutshell:

• Great look and feel at reasonable – actually very pleasant – weight and size. One of Canon’s sexiest lenses IMO.
• There’s frequent reports of its front ring coming off (google that).
• Despite what people say its sharpness is good at f/1.2 and very good further down. In the center where it matters.
• Close-ups at f/1.2 seem much less sharp to me but I haven’t explored that in detail yet.
• Otherwise average optical perfomance with all the little quirks you’d expect from a superfast lens: vignetting, distortion, bokeh fringing, field curvature.
• Autofocus is quite swift and usually very precise at f/1.2 even in low light.
• Notorious for its focus shift when stopped down until the increasing depth of field catches up, typically noticeable at ranges below 2m with apertures down to f/4. Flat subjects will be out of focus, heads will show sharp temples only.
• Very good backlight performance.
• Superb colors.
• Amazing bokeh in most situations.

I chose the 50L over the Sigma (both available at 20% price advantage in Tokyo) because I always loved its unique painting-like look which I recognize from any photo in a second and that ideally matches my more introverted photography style. Its medium angle and large aperture are great for visual storytelling because they subtly emphasize your subject rather than „isolating“ it.

I love my 50L to bits, but I also find myself taking random „test shots“ because the focusing feels not foolproof. I tried the Sigma Art at fairs and dealers and it seems a close to perfect lens. The pictures are great but they don’t have the particular magic of the 50L. If I did weddings or advertising photography where dependability and sharpness matter I’d choose it over the finicky Canon in a second.

So it all depends on your preferences.

If I'm near the MFD, I either shoot at f/1.2 or stop down enough so the depth of field is deeper than the focus shift. This theoretically limits creative choice, but is pretty easy to deal with in practice.

UKmitch86 wrote in post #17204681
Is your body able to do MFA? Have you done so?

it's not a MFA issue. Where you're near MFD, and you stop down, your focal plane changes on you.

you can throw the camera to manual focus and the sympton still occurs! (or so I've read. I havent seen the issue in the years I've owned it)