Nice review Justin. I had purchased this lens a while ago and had to return it three times due to none of them are able to focus correctly without micro adjustment. Once they were adjusted the images were beautiful and I was able to capture tack sharp images at f/1.4. Though I had returned it seven months ago due to it would not work on bodies that does not have build in micro adjustment function, I had always missed it.
Last week, I decided to purchase it again and this time with the USB DOCK. The copy I received still needed micro adjustment to work; however, after spending two nights of adjusting and testing all focusing ranges in the Sigma USB Dock software, I can now say that it is tack sharp without any micro adjustment ☺.
Now, the big elephant standing in the room is: "would I need to recalibrate the lens again if I buy another Canon body in the future?" Luckily, I do have access to cameras and after testing my calibrated Sigma 50mm f/1.4 ART on a T5i, 7D Mark II, 5D Mark III and 1DX with multiple photographers, I now can confidently say that no calibration or micro adjustment will be required once a copy of a 50mm f/1.4 Art is calibrated correctly with the Sigma USB Dock and will work on any compatible Canon bodies.
By the way, this lens will also works (auto focus with all 61 focus points) with both Kenko 1.4x and 2.0x Teleplus Pro 300 DGX teleconverters on a 5D Mark III (so as Tamron 150-600mm DI VC USD but not the Tamron 28-300mm PZD VC). Using 1.4x @ f/2 images looks like taken from a "soft focus" lens; however, when using the 2x @ f/2.8 it is sharp (that was unusual!). Both become sharper when closed down one stop.
Thanks again for reviewing this product and nice to see your beautiful work on your website and flickr. Heavy it may be, I still rather use this lens than any other 50mm f/1.4 (or f/1.2) out there by any other manufactures.
I had a similar experience.once this AF is fine tuned its superb ,even wide open and color and contrast is very good,its a great lens..a steal at this price.