Compared to Canon EF 50mm f/1.2L
The RF 50mm f/1.2L USM is the first 50mm prime lens released for the Canon R mount and currently faces no native mount competition.
That said, the RF 50mm f/1.2L USM is in many ways the spiritual successor of Canon EF 50mm f/1.2L USM lens, which has been available for the EF mount since 2006. While the RF 50mm f/1.2L USM can’t be used on Canon’s DSLR camera bodies, the EF 50mm f/1.2L USM can be mounted on both the EOS R and EOS RP via the EF to R adapter. The EF 50mm f/1.2L USM sells for $1349, which greatly undercuts the $2299 price tag of the RF 50mm f/1.2L USM. For EOS R users, the choice between the RF 50mm f/1.2L USM and EF 50mm f/1.2L USM is a complicated one. Below, we will take a look at how the two lenses compare to one another.
Build Quality Comparison
Both lenses feature a professional-grade build with a weather-sealed design. The new RF lens looks and feels more modern, with the EF variant very much looking the part of an earlier generation Canon L prime lens. With the two lenses side by side, the immense size difference between them is clear; the RF lens dwarfs its EF counterpart.
In specifications, the RF 50mm f/1.2 measures 89.8mm in diameter and 108mm in length. The EF version is 86mm in diameter and 66mm in length by comparison. The RF lens weighs 950 grams versus just 580 grams for the EF lens. In hand, the mirrorless version feels nearly twice as long and heavy as the DSLR lens, and this difference is not insubstantial when shooting for more extended periods. A big reason for the difference in size is all the extra glass found in the RF 50mm f/1.2L USM – 15 elements versus just 8.
In terms of features, the most obvious difference is that the mirrorless lens adds a control ring for adjusting various settings customizable from the camera menu. However, the EF 50mm f/1.2L USM can also benefit from a programmable Control Ring when it’s mounted on the EOS R via the EF to EOS R Control Ring adapter. So, if you use both lenses on the same camera, the major differences really are just weight and size.
Autofocus Performance and Accuracy Comparison
Both lenses offer a good autofocus performance when mounted on the EOS R, with relatively fast focus acquisition speeds and high accuracy. In day-to-day use, the RF 50mm f/1.2L USM feels a bit quicker to acquire focus, especially when shooting in low light environments.
Bokeh Comparison
An essential aspect of any ultra-wide aperture 50mm prime lens is the quality of its bokeh, and in most situations the two lenses have a similarly excellent bokeh rendering. Here is a direct comparison where both lenses were shot at f/1.2. I didn’t caption either image to say which is which, so you can compare more fairly if you prefer one rendering more than the other:
Can you guess which lens took which image?
The first shot is from the RF 50mm f/1.2L USM, while the second is from the EF 50mm f/1.2L USM. To me, they look very similar overall, with no real benefit for either.
Here are more samples of the same scene, taken at f/1.4, f/2, and f/2.8 with the RF lens:
f/1.4
f/2
f/2.8
Corner Bokeh Comparison
Even though the previous comparison shows high-quality bokeh on both lenses, there are some differences when viewing the corners of the frame. Specifically, the EF lens’s background blur sometimes manifests as very nervous bokeh in busy images. The below crops, taken from the edge of the frame, highlight this behavior. You’ll also notice the high amount of bokeh fringing in the crops from the EF lens in the following examples.
In comparison, the RF 50mm f/1.2L USM doesn’t show any signs of this nervous bokeh on the periphery of the frame, and only very mild color fringing:
Image Quality Comparison
For many photographers, the most important difference between these two lenses is their image quality – specifically sharpness. As you can see in the crops below, the new RF lens blows the older EF lens out of the water when it comes to image sharpness. The following crops are from the center of the image:
The RF version is clearly ahead from f/1.2 to f/2.8, especially visible at the lens’s widest aperture. Here are more center crops from f/4 to f/8:
Differences are more minor here, especially by f/8, but the mirrorless lens is still ahead overall. But how do the corners compare? Here’s a comparison from f/1.2 to f/2.8 in the corners:
As you can see, the RF lens is vastly better in the corners. It’s not even a contest; the mirrorless lens is sharper at f/1.2 than the DSLR lens at f/2.8! Now let’s take a look at f/4 through f/8 on these two lenses:
Again, the RF lens is clearly ahead, although the differences are starting to get smaller by f/8, where the EF lens finally starts to show very good performance. That said, it is truly remarkable that the RF lens is comparable overall at f/2.8 to the EF lens at f/8. If sharpness is your reason for buying one of these lenses, the RF is certainly worth the extra price.
Also note that the RF 50mm f/1.2L USM is much better corrected for lateral chromatic aberrations. The EF counterpart struggles quite a bit in this regard, especially in the corners, regardless of aperture. And, as shown above, the mirrorless lens has much less bokeh fringing, especially at its widest aperture. By comparison, the EF 50mm f/1.2L USM suffers from substantial levels of bokeh fringing at f/1.2 till f/2, with an improvement seen at f/2.8 and the problem mostly gone by f/4.
Canon RF 50mm f/1.2L USM vs Canon EF 50mm f/1.2L USM Conclusion
Overall, it is hard not to appreciate the work Canon has put into the RF 50mm f/1.2L USM lens, which handily bests the EF 50mm f/1.2L USM in almost every regard. Price, of course, is in the DSLR lens’s favor (again, $1349 versus $2299), and so are price and weight. But optically, there really is no contest. The RF 50mm f/1.2L is one of Canon’s best lenses – and among the best f/1.2 lenses of any manufacturer, if not the best (at least until the upcoming Nikon Z f/1.2 lenses give it a run for its money).