It seems that for once they were a bit overwhelmed by Canon’s latest optical masterpiece. From the conclusion:
[…] the R lenses are not only entirely new optics, they are also largely new electrical and mechanical systems. There are a lot of different things in here that we haven’t seen in any Canon EF lenses. Some of them we should have expected, like the increased electronics going to the control ring. Others we don’t really understand yet, like the tension spring in the ring USM motor or the increased electrical shielding.
[…] We also saw lots of new stuff we don’t completely understand yet and a level of complexity we weren’t expecting.
[…] the RF lenses contain some new technology they [Canon, editor’s note] haven’t used before. There’s a lot of engineering that’s gone into these. Things are different inside here. As we’ll see in the next teardown we do, some of that is carrying over to at least some EF lenses. What does this mean? It means Canon has invested very heavily into developing the lenses of the R system. This level of engineering didn’t all happen in the last year, they’ve been working on this for quite a while.
You can see a few images of the teardown below, though I recommend you head over to Lens Rentals for the many pictures and the step by step description of the teardown. Just don’t do it a home yourself.
The Canon RF 50mm f/1.2L is a highly regarded lens, universally seen as one of the two lenses Canon made to showcase the possibilities of their new RF mount (the other one being the RF 28-70mm f/2L.
[…[ it is quite obvious that the Canon RF 50mm f/1.2 USM L is an awesome lens … with a similar awe-inspiring price tag. In relation to other lenses in this class, the performance is already superb at f/1.2. Yes, the outer image region is not truly stellar but it’s impressive nonetheless. The image quality is extreme at medium aperture settings – across the image frame that is. Low lateral CAs contribute to the very high image quality perception. Image distortions are generally no issue. Vignetting is though – at least in its uncorrected state. There is some heavy light-falloff at f/1.2 and f/1.6 but to be fair – that’s to be expected. Most users will not (should not?) buy the lens for its sharpness but for its shallow depth-of-field capabilities. While not truly exceptional, the bokeh is very good with a smooth rendition in the focus transition zone. Out-of-focus highlights are nicely rendered in the image center, less so towards the image corners. However, that’s a physical limitation really. We were also very impressed by the very low bokeh fringing. Yes, you may spot some traces at f/1.2 but it’s not really relevant anymore from f/1.6 onward – and that’s a very rare characteristic. Read the review…
Optical Limits gives it a “highly recommended” rating.