Keep EF-S Lens on Old Camera or Replace with RF Lens on New Camera?

^ Very nice picture
The 15 is very useful and significantly wider than the 18
Therefore i prefer the 15 85 over the 18 135

Since you will be going from APS-C to full frame camera, you will need to replace the lens, too.

Yes, it's possible to use an EF-S lens on a full frame R-series camera, via the adapter. HOWEVER, images will be cropped significantly. With a high resolution camera like the R5 this is "doable"... not great, but possible. But on a 20MP R6 it would be a disaster. An APS-C crop from the R6 will end with less than 8MP!

Some good news is that used EF-S 15-85mm lenses sell for around $400 (new it's an $800 lens). It just so happens that's the price of one of the RF 24-105mm lenses... the smaller, lighter "STM" version with the variable aperture list price is $399. There also is the more expensive f/4 USM version that lists for $1299.

If you buy "in kit" with the camera, you should be able to get either of the RF lenses for a bit less than those prices.

EDIT: Sorry, my bad. You wrote Canon R6 Mark II, which is a 24MP camera. That's a wee bit better... but still needs a full frame lens on the full frame camera. An APS-C crop of an R6II image will end up between 9 and 10 MP.

Some more good news.... when bought in kit with the R6II, the RF 24-105mm f/4-7.1 IS STM lens only adds $300 to the cost of the camera. So if you manage to get the $400 that's typical for the EF-S 15-85mm sold used, you will end up ahead a little.

Thank you all for your responses. For now, it looks like I'll hold on to the 550D along with the 15-85 lens since I'm already going to be buying a telephoto when I buy the R6 Mark II. I'll use the 15-85 on the 550D more for wider angle shots that I wouldn't be able to get with the telephoto on the other camera.

Why not get the R7? Zero compromises on resolution, and you actually get substantially more resolution over the 55D.

What is the crop factor on Ef-s to rf? Have a decent Macro lens that I haven’t been able to use after swapping to an ef mount.

sickforska wrote in post #19450470
What is the crop factor on Ef-s to rf? Have a decent Macro lens that I haven’t been able to use after swapping to an ef mount.

If you have a full frame EF Macro lens, and adapt it to an RF full frame body, there is no crop factor.

What lens and what body do you have?

TeamSpeed wrote in post #19450171
Why not get the R7? Zero compromises on resolution, and you actually get substantially more resolution over the 55D.

This makes a lot of sense.

The R7 is 32.5MP, compared to the 6D Mk II's 24MP.

The R7 shares much the same high performance AF system of the R6II and R3.

Plus the APS-C R7 would be fully usable with the EF-S 15-85mm (EF to RF adapter req'd).

Yes, the full frame camera can be expected to handle low light conditions better... to be able to use higher ISO before noise becomes a problem. However coming from 550D to R7, the new camera will be usable about a full stop higher ISO than the older model... Keep in mind that's with nearly double the resolution! The full frame camera would probably be good for yet another full stop higher ISO than the R7... two stops higher than the 550D. (We'll have to wait and see, once the R6II gets tested).

Maybe best of all, the R7 is $1000 less expensive than the R6 Mk II!

By the way... It makes more sense to put a telephoto on an APS-C camera and a wide angle on full frame.