the first thing I'll say is HAVE YOU ACTUALLY USED THE 50L 1.2 ? because is is such a difference form the 50 1.4usm. It is such a different piece of kit and you will notice that instantly. I had been lamenting over getting it compared to the 1.4 specs, heard about bad or slow focusing mainly and that 1.4 is sharper, but those or so over exaggerated. And especially when it comes to using it , then seeing the images it produces afterwards.
It feels like a tank and on my first test in low light the 1.4 was hunting and not focusing and the 1.2 got it less than a second. My 1.4 wide open is so soft and unusable unless I want a soft glowy and fringing look. The 1.2 is not.
And more importantly the 1.2 just renders scenes much much more beautifully images have more of a 3D look to them thats really smooth at the same time. I had always thought the 1.4's sharpness and rendering was a bit harsh though.
Now those charts posted on MTF must be way out, as everything I've read shows the 1.2 is much sharper than the 1.4 up to 2.8 or so then the 1.4 is sharper. And from my tests the 1.2 is not as less sharp as tests produce in the real world.
However none have really blistering focusing speed I'd say the 1.2 is twice as fast and has less tantrums while trying to find focus which is a big thing and much more reassuring.
As you guys always ask when someone pipes up about lens selection, here are my shooting needs...
- I am an enthusiast only, been shooting about 9 years now
- Currently happily using a 5D3, so climbing up to ISO 6400 is not a problem.
- I never shoot in a studio environment.
- I almost never use a flash.
- I don't mind vignetting... In fact, I kind of like it sometimes
- I'd rather crank up ISO than shoot fully open as everything is soft in the corners
- I am in really low light, handheld situations all the time. My subjects generally are not moving, but I occasionally shoot at rock concerts. I generally prefer stopping down for sharpness and more useful DOF with IS than getting handcuffed into having to shoot fully open and accept softness and minimal DOF.
- High priority needs for this length: Walkaround, Candids, Kids, Handheld low-light (Not moving subjects)
- Medium priority needs for this length: Handheld Low-Light (Concerts), Street, Portraits
- Low priority needs for this length: Landscapes, Handheld low-light (Gymnasium Sports)
- Zero need for this length: Video, Macro, Field Sports, Wildlife
- I'll pay more for better gear at this stage.
- Weather sealing is great for a landscape-prioritized lens, but as I live in a place with near zero inclement weather, sealing is not a must for me in this length.
- I rarely take things to print.
- I generally shoot my Canon 50mm F/1.4mm in the F/2 to F/5.6 range. I appreciate what large aperture glass offers, but I almost always stop those lenses down for more sharpness, more working DOF, etc.
What I'm considering...
Now you say that most of your subjects arent moving then either should be fine unless your shooting in really dark environments a 5D III should be fine for most places, maybe a really dark bar would test it. But remember these aren't miracle machines to all situations! We now have imho stupidly high ISO options at our hands, and a lot of lenses / AF cant cope and imagine how difficult it would of been in the past on film and MF lenses. So I have to say to people get real about where you can expect to shoot and get a decent result, just because Canon says you 'can' shoot at 128000 . It or even 32000 is going to get compromised results. Now if its only capturing a moment that wasn't previously able to be captured then thats fine isn't it? And like you say you are an enthusiast. Should you expect to have a shooting and viewing experience and expectation that is similar to the equipment being used in prime situations and conditions to give an absolutely stunning result.
Remember photography is a skill not a demo or expectation of technology just because you've bought it.
Release the artist in you and relax that engineer hat you don and you will learn more, understand photography & images in new way. An engineer and artist combined is very powerful combination..