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Question about EF Lens Compatibility on RF Mount


Hi All,

Currently I’m using my 5d mark 4 and love it, I’m looking at taking the plunge and will be aiming to purchase a r3 in the upcoming months.

I’m also in a little bit of a lens situation. The are some lenses I’m looking at upgrading in my kit, for example my nifty fifty a 50mm 1.2.

My main photography work is product photos, music/event photography and boudoir.

My consideration is purchasing lenses for my current Ef mount, and then use an adapter to use them on the r3. This would also allow me to use the lenses interchangeably on both cameras, and use the mk4 as a second camera and not need to change lenses when shooting gigs.

I just wanted to see what people think about using the lens adapter. Or if the is a huge advantage in purchasing the rf glass.

Just trying to plan out my purchases for the upcoming year



"Nifty Fifty" is the nickname for the EF (or RF) 50mm f/1.8 lens.   So double-checking if you currently have the EF 50mm f/1.8 or EF 50mm f/1.2 L.   If you have the f/1.8 version, then I would recommend not getting the EF 50mm f/1.2 L and instead use that money towards the RF 50mm f/1.2L as the RF version has increased image quality.

EF to RF adapters work very well.  But be sure to stick with the Canon brand.   The base EF to RF adapter will work very well, but it may also be good to purchase the adapter with the control ring just to give you more options when using EF glass on your R-series body.


EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L, 600EX-RT (x6), ST-E3-RT
EOS C70, RF 24-70 f/2.8L IS, EF-EOS R 0.71x


As always Ricky has excellent advice. 

You will inevitably purchase RF lenses once you have tried them with your future R3.  The control ring adapter will ease the transition, but I would not invest further in EF glass.  Keep the 5D4 (great camera) as a 2nd shooter or back up.  In the end however, you will go RF on the R3.  I assure you.  😉

Bay Area - CA

~R5 C ( ~RF Trinity, ~RF 100~400, ~RF 100~500, +RF 1.4x TC, +Canon Control Ring, BG-R10

~6D2 (v1.1.1) Retired ~EF Trinity, others ~DxO PhotoLab Elite ~Windows10/11 Pro ~EVGA RTX 3080Ti FTW3 Ultra ~ImageClass MF644Cdw ~Pixel6 ~CarePaks Are Worth It


This is difficult to advise on - if it was me, it would depend how many EF lenses I already had, how happy I was with them, how many more lenses I intend to purchase and how long I intended to retain my 5Dmk4 after purchasing an R3.

The EF 50mm f/1.2 is an expensive lens, the RF 50mm f/1.2 is even more expensive but it's also a significantly better lens. If I already had the EF lens, but my shopping list included a number of additional lenses, I think my next lens purchase would not be the RF 50 f/1.2. Instead I would buy a different lens from my list of needs, something that will take pictures different from the ones I can already take with the EF 50.

As others have already commented, we think you'll sooner or later decide on RF glass. When I went mirrorless I thought I would retain quite a few of my EF lenses, particularly the ones I was fond of. But it quickly became clear to me that native RF lenses would serve me better. I hadn't retained an EF body, though, that would have complicated the decision.

Maybe the solution is to buy two R3 bodies and dispose of the 5Dmk4 and your EF lenses in order to fund RF replacements...

R6mkII, various lenses, speedlites. Also legacy Canons going back to T90 and even A1.