Should I buy ef lenses for my EOS R6 II?

[dikebki1]

Hi I was thinking about adding a 70-200 f2.8 to my inventory. The rf mount is very expensive so I thought about buying a used ef mount lens. Some friends of mine said they don’t see any loss of quality with the ef and a adapter, some say there is a lot of loss in quality. I was wondering if you could share your experience and if you have any advice? Thanks 🙂

[deebatman316]

I would not invest ANY EF lenses if you own an RF Mount camera. Unless there isn’t an RF Mount equivalent lens. Older EF lenses have limitations when adapted to RF Mount cameras. Such as the highly advanced AF system not being fully supported. Or 12 fps being available.

[March411]

deebatman316 makes a valid point. For me the question comes with a caveat or two. If you can't afford the RF version and the lenses you are thinking of purchasing are not reaching end of service it may make sense.

I have purchased and still own several EF lenses from both Canon and Sigma. Personally end of service is my biggest consideration. There are three different versions of the lens you inquired about, only the EF70-200 2.8L IS III USM should be a consideration.  

• EF70-200 2.8L USM: May 2026
• EF70-200 2.8L IS II USM: May 2025
• EF70-200 2.8L IS III USM: Undecided

When I asked myself the same questions as you I decided to dive deep, I did in this post I went out and did a fair amount of research. I left my findings in the Canon knowledge base, check out this link there is some decent information with links for reference: Canon (MILC) - Lenses - EF or RF 

Again deebatman316 point is valid, EF lenses are heavier and RF lenses have a 12-pin connection to the camera, while EF lenses have 8 pins. This allows RF lenses to communicate with the camera faster, more efficiently and offer more functionality. That being said, the EF lenses I maintain work far better on my MILC then my DSLR's, fast and overall better keeper rate but they are being mounted on a superior R body.

If you decide to go EF don't make the same mistake I did and try third party adapters, they are very inconsistent! New or used the simple Canon EF - RF adapter will greatly improve the performance of the lens.

[shadowsports]

The RF 70-200 f2.8 is a favorite of mine.  As my colleagues pointed out, investing in EF glass is a losing proposition in the longer run.  If you want the flexibility of being able to use an RF TC, then you'll need to buy the 24-105 Z internal zoom model.  I really like the compactness of the first gen 70-200 and don't mind that it's an external Zoom.  I also rarely use a TC so this is a non-issue for me.  The lens is extremely sharp and high performing.  It's exceptional for portraits and indoor venues with low light.  The EF model has these same attributes.  In the end, however, lenses are your real investment in photography.  Body's come and go.  Have you considered Canon refurbished?

https://www.usa.canon.com/shop/lenses/refurbished-lenses