Tom of BorrowLenses compares Canon lenses for different mount types in this Canon RF vs EF lens comparison.

Canon RF lenses are for the new Canon EOS R full frame mirrorless system, Canon EF lenses fit on Canon DSLRs (APS-C and FF). So, which are better? Are the RF lenses an improvement over EF lenses? For this purpose these lenses have been compared:

• Canon RF 50mm 1.2L
• Canon RF 24-105mm f/4L
• Canon EF 50mm 1.2L
• Canon EF 24-105mm f/4L

All tests done on a Canon EOS R (EF lenses mounted via adapter). And here is the video with the Canon RF vs EF lens comparison:

Canon puts a lot of emphasis on their new lens mount system, and for a good reason. Some of the so far released lenses are nothing less than spectacular. An interview with the engineers designing and developing RF mount lenses is here.

The Canon RF 50mm f/1.2L is one of the boutique lenses Canon made for the EOS R, the other is the Canon RF 28-70mm f/2L. If you have any doubt left that the RF versions are an improvement, then have a look what DxOMark says.

It’s also pretty interesting to read what the experts at LensRentals have to say after a teardown of the RF 50mm (emphasis mine):

[…] 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.

Guess there is definitely a lot of new technology in Canon RF lenses compared to EF lenses.