Using a lens with the Canon RF mount on an EF mount camera is mechanically impossible. This is because, as a mirrorless lens mount, the RF mount is meant for lenses without a mirror.
I’m Caleb, and I have over five years of photography experience. My primary specialty is sports photography, and I’ve shot several sports and leagues from the college to semi-pro levels.
In today’s article, I’ll explain why you can’t use an RF lens with an EF camera. I’ll also look at why Canon created the RF mount in the first place and where Canon’s lenses might be headed in the future.
If you’re lens shopping and curious about the differences between RF and EF lenses, keep reading for the full breakdown.
Can I Use an RF Lens on an EF Camera?
This won’t work from a mechanical perspective and has to do with how both mounts were designed.
RF lenses are meant to sit right against the camera’s sensor. This is possible because they’re made for mirrorless cameras, which, as the name suggests, don’t have a mirror. If you try to use an RF lens with an EF camera, the mirror will get in the way.
Thanks to this, there’s not really any fix for the problem. An adapter wouldn’t work, only removing the mirror. And by that point, you’ve inadvertently created a mirrorless camera, the type that the RF lenses were designed for in the first place.
Why Does the RF Mount Exist?
You might be wondering why Canon invested in creating a new lens mount that isn’t compatible with most of its cameras. While it’s impossible to know Canon’s motivations, there’s a good chance efficiency has something to do with it.
Mirrorless cameras make use of space more efficiently by getting rid of the mirror. Without this extra component, the lens can sit closer to the sensor, and the entire setup helps make the mirrorless camera smaller than its DSLR counterpart.
The RF mount is designed with that in mind. Canon needed a new lens mount to fully take advantage of the efficient setup of their newer full-frame mirrorless cameras like the EOS R, and the RF mount is the result we got.
While the mount is the odd one out right now compared to the far more common EF mount, it will only grow in popularity in the future, as Canon has emphasized mirrorless cameras in their future plans.
Will the RF Mount Replace the EF Mount?
It’s hard to say what’s in store for the RF and EF mounts in the future. Canon is moving towards mirrorless cameras over DSLRs; they aren’t the only company headed in that direction.
On the other hand, the EF mount is much larger than the RF mount right now. Thanks to the long history of the mount, there are tons of second-hand models on the market for accessible prices. Additionally, many photographers have built up extensive collections of EF lenses.
Because of its massive presence, it’s hard to see the EF mount disappearing overnight. It looks like Canon’s intentions are to eventually move on to the RF mount as their primary option, but for the foreseeable future, there should still be plenty of support for EF lens owners.
After all, camera lenses can last a very long time when taken care of. Newer EF lenses still have a long way to go before repair parts become scarce and RF lenses take over the market entirely.
Here are some other frequently asked lens mount questions.
What Cameras Are Compatible With Canon RF Lenses?
The RF mount was designed for the R series of cameras. This includes the EOS R, R5, R6, RP, etc. It’s important to point out that RF lenses don’t work with Canon’s M series cameras, despite the M series also being mirrorless.
Is Canon Discontinuing EF Lenses?
No, Canon is not discontinuing EF lenses at this time. And even if Canon officially ended manufacturing EF lenses, it’s likely they would stick around as one of the main lens options for some time after their discontinuation.
Are Old Canon Lenses Still Good?
Yes, you can still get excellent performance out of old lenses. Many photographers in demanding fields like news or sports start by using older high-end models to avoid paying the typically high costs for their newer counterparts.
Using Canon’s RF line of lenses with EF mount cameras is impossible. RF lenses are designed for cameras without a mirror, and no workaround like adapters can get around this.
Do you prefer the RF mount or the EF mount? Let us know in the comments!