topic Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS in Gear Guide

EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

mhrabar — Thu, 05 Feb 2026 02:17:46 GMT

Hey all,

We are looking to finally upgrade our 7D to an R7. How much performance would we be loosing from the V1 EF24-70 w/ an RF adapter to the bleeding edge RF24-70?

Same w/ the EF70-200 F2.8L - but this one is a V2, and tack sharp.

Thanks, Mike

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

SignifDigits — Thu, 05 Feb 2026 15:11:03 GMT

You will get a lot of replies with this one, I feel certain and get a lot of useful information. First, you might already be aware that a new Mark II R7 may soon be announced, as well, as, potentially, an R10 Mark II. I'm mentioning it just to be sure you're aware and can time your purchase according to your priorities.

The R7 has in body image stabilization (IBIS) rated at up to 7 stops. That will have a big impact for you in terms of low-light performance.

I can only speak to the EF 70-200 F2.8 L III IS USM. For the RF 24-70 range I personally just traded by RF 24-105 f/4 IS USM L in and bought a refurbished Canon RF 24-105mm f/4-7.1 IS STM as a part what I'm calling my "unholy trinity" - RF 18-35 f/2.8 L IS USM, RF 24-105mm f/4-7.1 IS STM, and EF 70-200 f/2.8 L IS III USM. This selection suits my own personal budgetary and photographic priorities.

Your version II of the EF 70-200 is no longer supported by Canon so if you ever need service you'll have to seek out a third party. Hopefully it will last forever and never need service. They are built to last, for sure. The internal focus mechanism of that lens is only mirrored in the RF Z version. The other RF 70-200 are externally extending zoom lenses - lighter in weight with excellent optical performance, but do pump air in and out as they extend and retract.

For RF vs EF, the RF auto-focus performance is often considered a bit better than the EF lenses, stabilization is a bit better and optical coatings a bit better. I cannot point to data to support those claims, but expect that it is probably all true.

As to functionality, I think the biggest difference is in the focus ring and Electronic Full-Time Manual Focus. The compatibility list https://cam.start.canon/en/H001/supplement_0060.html . There you will find that all of the RF lenses that have the wholly electronic focus ring which support this functionality. In practical terms this means you should not turn the EF lens focus ring when AF is enabled and you will not be able to get the 10x zoom during AF of the RF lenses by enabling "Electronic full-time MF" to ON and "Lens electronic MF" to "One-shot->enabled(magnify)".

This is a VERY nice fine-tuning-manual focus feature which you will not have with the EF lens.

I've included the full version of deebatman316' excellent knowledge base on this topic for you below:

Some of Canon's lenses offer what is called Full Time Manual Focus or Manual Focus Override when the lens is set to AF. Not every lens made by Canon especially in the EF Mount supports this and can be damaged. All RF Mount lenses support this EXCEPT the RF 75-300mm F/4-5.6 lens. This lens uses Micro Motor and doesn't support this as the focus ring is connected directly to the lens' focusing elements without a clutch to prevent damage. When Canon first offered Full Time Manual Focus it was implemented by a focus by wire system. But there were limitations to it such as it doesn't work with the camera's focus mode set to Servo AF or AI Focus. Or if the camera's metering were to go idle while the camera isn't being used. When the lens is unmounted from the camera. MF doesn't work either. Later to cut costs Canon came out out with a clutch override system which provided a mechanical means of this. This system directly connected the focus ring to the focusing elements of the lens. To prevent damage to the Ring Type USM AF motor a clutch was under the focus ring to allow the focus ring to slip against the AF motor. The only problem with this system is when the AF motor is active you cannot override focus. This may feel like push back from the lens' AF motor but this is NOT the case. What you're feeling is the clutch under the focus ring doing its job to prevent damage to the lens by allowing the focus ring to slip against the motor. When using an adapted Ring Type USM on the EOS R series set Continuous AF/ Preview AF to DISABLE. The lens will be constantly focusing when the AF motor is being driven by the camera and you cannot override focus. Instead you'll feel push back from the lens' AF motor which is normal. This is the clutch protecting the lens from being damaged. Other lenses with different AF motor types support focus override by focus by wire. Those lenses are below. Nano USM, STM, VCM & certain Ring Type USM use focus by wire for focus override. Micro USM was designed to be cheaper and not provide focus override while in AF mode. Only the EF 50mm F/1.4 USM lens allows this. This is due to an additional clutch system in the lens to allow focus override with the lens set to AF. Micro USM lenses lack a focus distance scale and spin the focus ring when the AF motor is active. The EF 50mm F/1.4 USM lens includes a focus distance scale and the focus ring DOES NOT spin when the AF motor is active. Older Arc Form Drive (AFD) lenses had a one way clutch. This clutch only allows either the AF motor or the focus ring to adjust focus. When the lens is set to AF the focus ring is disengaged from the lens' focus elements and will NOT spin when the AF motor is active. AFD lenses DO NOT offer Focus Override in AF mode. All RF lenses have moved to focus by wire. Most of these lenses use Nano USM, STM or VCM AF motors. Ring Type & Micro USM have been replaced by the faster Nano USM AF motor. Though the RF 85mm F/1.2L USM retains the Ring Type USM AF motor that its previous EF Mount counterparts used.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

ebiggs1 — Thu, 05 Feb 2026 16:14:16 GMT

WOW, that was long!

My answer is to try it. The adapter isn't all that expensive when you consider you'll be spending around $1500 for the new camera. I suspect the 70-200mm f2.8l you have will be just as good as it is today. Perhaps even the older 24-70mil will also.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

deebatman316 — Thu, 05 Feb 2026 16:26:06 GMT

Hi @mhrabar welcome to the forums. Yes your lenses that you own will work via an adapter. Just know there will be limitations with older EF lenses. Mainly older lenses cannot achieve 12 FPS in stills mode. Most DSLR cameras cannot shoot at that rate of speed. Or the highly advanced AF system. Features the lens doesn’t support the camera limits its usable features. Due to the lens’ older hardware which isn’t fully compatible. The amount of IS that you get will be dependent on the lens combination. Lens IS + IBIS work together. With older EF lenses you won’t be able to achieve the 7 stops of stabilization. That is mainly offered with RF lenses.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

SignifDigits — Thu, 05 Feb 2026 16:56:42 GMT

@ebiggs1 - It was long because I get paid by the word.... of course is $0.00 per word, but I like to offer value for service and be thorough 🙂 It helps when half of of the words were from deebatman316, who is, obviously very well-versed on the subject. It's a testament to him training me to check his KB before I wade into this topic.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

ebiggs1 — Fri, 06 Feb 2026 15:12:08 GMT

"...deebatman316, who is, obviously very well-versed on the subject."

Yes, it amazes me that some guys have the time to spend on the ole inner web searching and reading all that stuff.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

shadowsports — Fri, 06 Feb 2026 15:51:55 GMT

Greetings ,

Plenty of great replies.

My personal feeling, I'd go for the camera and new RF 24--70 f2.8, with a Canon adapter. The v1 of the EF lens is and remains one of Canon's best lens designs. With that said, this lens (v1) is prone to aperture diaphragm flex cable failure. It could work forever, but chances are it won't and at some point there is a very good chance it'll leave you stranded. If it's during a vacation, that would be a bummer. There are two philosophies of course. Drive it until it fails or replace it to avoid sudden or unexpected failure. The EF 70-200 f2.8, mkII (yours) and mkIII are both top performers (support max FPS) on the R7. Although the mkII is no longer under support, it has a pretty stellar track record of reliability in comparison. That gamble presents less risk over the long term. You'll want to upgrade to RF anyway, so the adapter gives you the option of beginning your migration now or one at a time If this is more amenable to your budget. It also give you a little more time to sock away some cash if you wanted to go for the Z series instead of the mkI. Personally, I'm very happy with the mkI even though it's an external zoom because it's so compact. This is a matter of preference.

Famous last words. Lenses are the real investment in photography. If done right they will move forward with you. Body's will come and go.

Coming from a 7D, the R7 represents a substantial upgrade. Using it in conjunction with L series glass, will make it that much more pleasing.

Re: EF24-70 F2.8L IS w/ RF adapter vs RF24-70 F2.8L IS

SignifDigits — Fri, 06 Feb 2026 16:12:19 GMT

As of this writing both RF lenses in that focal length range are available refurbished. For my skill and use level it isn't worth the very nearly $2,000 difference in price. I would think that's especially true on an IBIS APS-C camera, but even for my R6 Mark II it isn't for me. YMMV