Compatibility of R5/6 and EF/EF-S lenses

[mjessa]

Gentlemen: I'm considering upgrading from a Canon EOS 7D Mk2 to either an R5 or R6.

Will the following lenses work (be fully compatible) with either of the bodies?

Canon Macro Lens EF 100mm 1:2.8 L IS USM
Canon Zoom Lens EF 70-200mm 1:2.8 L IS II USM
Canon Zoom Lens EF 100-400mm 1:4.5-5:6 L IS USM
Canon Zoom Lens EF-S 10-25mm 1:3.5-4.5 USM
Canon Zoom Lens EF-S 17-55mm 1:2.8 IS USM
Canon Extender EF 2x III

If not what are my choices (upgrade the lens, firmware, adaptors)?

What else should I be aware of before investing?

Things I am hoping to achieve: Autofocus when using 100-400 and the extender, faster focus on subjects (especially for bird photography).

Thanks and kind regards,

[Waddizzle]

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@johnrmoyer wrote:

The 1.6x crop with the EOS R5 makes a much smaller raw file. The other aspect ratio crops are as you describe.

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That’s good thing!  I was a little puzzled to see the full size RAW files in crop mode.

[ebiggs1]

The reason the Canon tel-con won’t work with your EFS lenses on the R series is because they never work with a Canon tel-con.

[mjessa]

Thanks @ebiggs1

Yes I am aware of that combination. I only use the x2 tele con with my 70-200 and with 100-400 in very bright conditions

[shadowsports]

Greetings,

Wanted to add these comments.  If you are going to use any EF-S lenses with a new body, I would not recommend the R6, as you are only starting with 20MP's in the first place.  I'd stick with the R5 for this reason.

Other options:

Sell your EF-S 10-25mm 1:3.5-4.5 USM & EF-S 17-55mm 1:2.8 IS USM

Replace with EF or RF - 16~35 or 24~70.  Note, too, you may get some undesirable vignetting with a EF-S 10mm lens on a mirrorless body using a EF>RF adapter, due to distance of focal plane. (Distance of lens mount flange to sensor). 

If I'm wrong about this, please correct me.  Other option, stick it out a wait for the R7

[johnrmoyer]

Here is another with an EF-S lens. I used the focus stacking in the EOS R5 menu and depth compositing in the Canon DPP software. I used a tripod, my cell phone as a remote shutter, EF-S 18-135mm f/3.5-5.6 IS USM, and stacked 15 images. There was no wind that day. https://www.rsok.com/~jrm/2021May19_birds_and_cats/2021may10_allium_DC_1021c.html

I do not know about the EOS R6, but I expect that with the EOS R5 your EF-S lenses will work better than they do with your old camera.

[FloridaDrafter]

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@mjessa wrote:

Gentlemen: I'm considering upgrading from a Canon EOS 7D Mk2 to either an R5 or R6.

Will the following lenses work (be fully compatible) with either of the bodies?

Canon Macro Lens EF 100mm 1:2.8 L IS USM
Canon Zoom Lens EF 70-200mm 1:2.8 L IS II USM
Canon Zoom Lens EF 100-400mm 1:4.5-5:6 L IS USM
Canon Zoom Lens EF-S 10-25mm 1:3.5-4.5 USM
Canon Zoom Lens EF-S 17-55mm 1:2.8 IS USM
Canon Extender EF 2x III

If not what are my choices (upgrade the lens, firmware, adaptors)?

What else should I be aware of before investing?

Things I am hoping to achieve: Autofocus when using 100-400 and the extender, faster focus on subjects (especially for bird photography).

Thanks and kind regards,

---

My wife and I have been using the R6 for over a year and I've been using the R5 for seven months now. Like you, we originally planned to use our EF lenses with an EF to RF adapter, but that plan fizzled out and we now use RF glass on both. Not that the EF lenses we have (3 of which are on your list) aren't great lenses, just that what RF glass we have bought is superior to it's EF counterpart. I wouldn't expect anything less since RF lenses are designed for the R cameras. Now, how much better RF is over EF is probably subjective and whether or not it's worth upgrading to RF when you already have a pile of EF glass will play a factor. Personally, I have no regrets and I can see the improvements in IQ as well as technology... RF "L" glass on an R5 is a thing of beauty.

Rick is spot on about the EF-S lenses, except I wouldn't and didn't buy another EF lens to replace our EF-S wide angles. If you choose to use your current EF-S glass, you will loose over half of your megapixels. Yes, it's usable, but you better be prepared to fill the frame because cropping is near impossible if you want to do any printing. The R5 is a little better, but you are still dropping from 45mp to 18 when using the EF-S (8mp on the R6). Another reason I wouldn't replace EF-S with EF is RF is the future. No sense investing in an EOS R5 or 6 and buying new glass made for another format.

On a side note, we moved to the EOS R5 and 6 from an EOS 5D mark IV, an EOS 7D mark II, and a Rebel T7i but have owned a bunch of Canon gear going back to the 35mm film days. We both shoot birds and a variety of macro subjects.

Also, I used the EF 1.4X III extender on my EF 100-400mm L II on both the R5 and R6 and didn't much care for the IQ, so I'm not sure what your results will be with the 2X. Obviously, we all have our level of "acceptable results". I'm a little tough to please 🙂

I know I've left something out, so please feel free to ask. I've been using these two cameras a while now 🙂

Newton