If I were to purchase the (newly-announced) Canon EOS R5 and wanted to use one of my existing EF-mount lenses, can I use it with the EF-EOS R adapter or do I need to purchase a different adapter?

The product specification page explicitly mentions that it is compatible with the EOS R, but doesn't mention any other mirrorless cameras.

  • Why would you think EF→RF adapter(s), there are four variations - three with drop-in filters or a control ring, made to allow using EF lenses on RF mount cameras wouldn't work with the R5, which is an RF mount camera?
    – Michael C
    Jul 15, 2020 at 9:14

3 Answers 3


I am sure the product specification page has not been updated since the launch and which is why it is mentioning the camera bodies available at around that time. There is no reason for the rf-ef adapter to not work since they communicate via the same protocol/mount. If that would have been different for each camera (not consistent across all cameras with the same mount) then future lenses would also not work with previous cameras of the same mount!

So I am sure, unless Canon puts out something like a compatibility matrix of lenses/adapters vs cameras, all rf mount lenses/adapters will continue to work with all rf mount bodies.

That is the whole point of standards and good designs - i think the latest EF lenses continue to work as designed with the EF film bodies!

Hope that helps!

  • Just to add: my assumption was you are using canon lenses and adapter not third party items (sigma tamron etc). If its the later then please do check once (by renting or borrowing) or ask the manufacturer for known issues because there have been cases of compatibility issues of that kind in the past. If its all canon then i wouldn't worry.
    – suvartheec
    Jul 15, 2020 at 7:34
  • 1
    I can attest to the EOS EF compatibility: I mounted an EF lens released in 2017 on an original EOS 650 film body. The autofocus, aperture, and image stabilizer all worked perfectly.
    – Nayuki
    Jul 15, 2020 at 15:29

When that product specification page was written, the EOS R was the only RF mount camera available. The RP, R5, and R6 hadn't been introduced yet.

The same EF→RF adapters that work with EF lenses for the EOS R and EOS RP will also work with the newer R5 and R6.

In the EOS R5 Specifications document the following two entries are listed as Compatible Lenses:

  • Canon RF lens group (excluding EF, EF-S and EF-M lenses)
  • When using Mount Adapter EF-EOS R: Canon EF or EF-S lenses (excluding EF-M lenses)

There are currently four varieties of Mount Adapter EF-EOS R available:

  • 1
    The same EF to R adapters are listed as an accessory for the EOS R5 camera
    – cmason
    Jul 17, 2020 at 16:58
  • @cmason They're not listed in the accessory section at the R5 support page at Canon USA because Canon, at least in the USA, doesn't consider them accessories. This is similar to the EF 1.4X and EF 2X extenders, which Canon USA lists as "lenses". Even though the adapters have no glass they're still listed in the "Lenses" section, rather than "Accessories", at Canon USA.
    – Michael C
    Jul 18, 2020 at 4:52
  • atMicheal C was referring to the US 'shop' page, where they are shown as 'recommended accessories' to accompany your purchase.
    – cmason
    Jul 20, 2020 at 12:43

You can look at the official Canon EOS R5 User Guide (PDF) for information. Download the guide from the Canon website. There are over 900 pages but many live links so you can easily jump around inside the document. Go to page 878 and there you should see a chart that shows all current items that can be connected to the camera. One thing you may like to consider is that, though you can connect EF lenses, not all of them will provide access to all the features of the camera. For example, focussing speed will not necessarily be as fast as with the dedicated RF series lenses. I hope this is useful for you.

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