In the Field: EF vs RF Canon 50mm f/1.2 Lenses

What's the difference between Canon EF and RF lenses? Ian Howorth compares Canon's RF 50mm f/1.2 and EF 50mm f/1.2 lenses and explains what this means for photographers.

When Canon first announced the RF 50mm f/1.2 L USM, our initial reaction was that it'd just be a rehoused Canon EF lens. You wouldn't really blame us for thinking that, would you? When the Canon EOS R was finally announced with its initial lineup, many felt it could've been a rushed job. Perhaps to catch up with the runaway success of the Sony A7 and other full-frame mirrorless cameras?

The first thing to say is that I'm not a pixel peeper. Ultimately, it's the image that counts. Equally, for some people, the unwanted characteristic in a test might be something another photographer seeks.

However, most people don't just randomly choose lenses blindfolded. They have to make a choice. Each lens has certain characteristics that might be deal breakers—aberrations, bokeh, corner sharpness, etc.

The test was by no means scientific. Some shots were set to aperture priority, so there may have been small changes in exposure. But, looking at the metadata, the difference was never more than a third to half a stop. What is consistent, however, is the aperture these images were shot at—always f/1.2.

Both these images are very pleasing to the eye, with the Canon EOS 5D Mark IV and EF 50mm f/1.2 L USM lens combo displaying a little more warmth than the Canon EOS R and RF setup. You begin to see the differences between the two when you get closer.

The first thing you notice is the purple fringing, which is an aberration—it's common with many lenses, particularly when shot at maximum apertures. This can be minimised if the background with which the aberration is contrasting hides it. As we can see here, the contrast between the yellow blind works against it, amplifying it somewhat.

The Canon EOS R with RF 50mm f/1.2 L USM combo handles the aberrations in a much more controlled manner. While they're still there, they are less of a problem than with the older lens.

I was astounded when I saw this image. The centre image sharpness and control of fringing and aberrations had me check my metadata to ensure I hadn't stopped down this lens by mistake.

What about those corners? Shooting at f/1.2, I had little hope for edge-to-edge sharpness, but I was really impressed with the EF 50mm f/1.2.

Corner sharpness is no easy feat to achieve this side of £25,000 cinema glass. So, rather than wishing for perfection, I'm happy to settle for pleasing renditions. While the corners of the image are not sharp, they have an almost dream-like feel, which aids the image elsewhere.

However, the RF lens is in a different league. While those corners aren't perfect, the improvement is noticeable—the sharpness exhibited in the centre of the frame creeps ever closer to the far edges.

The lack of fringing, inherent to the lens, further aids the quality of the shot. This is because it doesn't affect the colour and rendition as much as the EF.

The focus was on the flower closer to the centre frame, and with such an ample single-colour background, this image was a great test for both lenses.

Unsurprisingly, fringing is all over the petals. However, since they are purple, this becomes far more noticeable on the green leaves against the blue background.

While still noticeable, you can see the fringing and aberrations are much more controlled with the RF lens.

So, it’s worth noting that the images would always be a bit different. They were taken with two different cameras and two different lenses. Renditions always have some variance that can't simply be put down to the glass. If that skews the results a little, I hear you.

However, this test compares two lenses from different generations to see the improvements in the field—what we can get away with and what we can’t.

I’m incredibly pleased with how the RF lens performed. It improved over the EF in terms of sharpness and optical artefacts, and I was astounded at just how good it was.

The Canon RF proved that it's not just a rehoused Canon EF 50mm f/1.2L USM, it's different from the ground up. This is a lens that Canon got right when they didn't need to. This level of sharpness at f/1.2 is unreal.

What about the EF? It's a little older and has a few more optical issues. But: so what? It has a unique way of rendering scenes at f/1.2, unmatched by almost any other lens. It has a certain personality, like the one that 21st-century cinematographers seek in mid-20th-century optics for their film for a specific look.

And that’s the crux of it: Canon RF vs. EF, two different lenses for two types of photographers. Take your pick; they’re both excellent."

For more differences between Canon RF and EF lenses, read our Canon RF vs EF 24-70mm lens comparison. Or check out more camera gear guides on the MPB content hub.