That's just for starters. The RF mounting face is 20mm in front of the sensor, the EF is 44mm, the bayonets are practically the same size, so the RF lens would be at least 35mm too far from the sensor to focus on infinity if you could make a mechanical adapter. The RF lenses communicate with the camera much faster than EF lenses do, using 12 contacts instead of eight. While RF mount cameras can also use the EF protocol, there's no reason for RF lenses to understand the EF protocol, so even macro focussing and opening the iris could be a problem.
that is good, info, thanks. but there 2 types of EF-RF adapters, one is for $99 and the other for $199. could you tell me what the difference is, please, if you know? appreciate it
There are three types; the plain adapter, the control ring adapter which adds the RF lenses' selectable control ring functions to EF lenses (handy if you're mixing EF and RF lenses and have got used to using the control ring) and a drop-in filter adapter. The last is available with either a variable ND filter or a circular polarising filter and a plain filter is available to maintain focus if you don't need ND or a polariser. That's useful for lenses that don't take filters, like the 17mm TS-E or various ultra-wide zooms. The VND filter is more even with wideangles at maximum effect than most front mounted ones. There are various knock-offs, I've seen a YKEASU version with an uncoated polariser and Viltrox caps. Kolari do a filter adapter with a wider range of filters.
The $99 version is just a basic lens mount adapter. The $199 adapter adds the control ring like many RF lenses have. You can assign a variety of specific functions to the ring. No difference in performance between the two.
i use Lee 100x100 or 100x150 filters and you can get adapter for primes to make the filters fit on any lens. so filters are not an issue.
I think it's more accurate to say "fit most lenses". it's a real challenge to fit a filter on a very wide angle lens like the EF 8-15 fisheye (180° angle of view) or the EF 11-24 rectilinear zoom (126° angle of view).
The Kolari variable ND filter is a lot more even across the field at 12mm on my Sigma 12-24mm (which otherwise can't take filters unless I use it with the APS-C lens hood that is threaded at the outside end) than my cheap front mounted on my EF 16-35mm is. The front mounted one gives the dreaded X shading at maximum extinction even at 24mm. Polarising filters show that the sky is polarised normal to the direction of the sun, so extreme wideangles can show dark bands in the sky whichever end of the lens they are on.
You don't have to, as they have slots for drop-in filters at the rear end.
Yes, you can. They have a POL, an ND and a clear filter. The last one is a dummy, so you can use the adapter as just that, an adapter, without any filter effect.
Aim for Meike drop-in filter adapter. I did compare it hands-on with Canon. Build quality is very much the same and Meike has smaller color shift at the max ND setting than Canon. Meike is MUCH cheaper. There is zero advantage and a slight disadvantage buying Canon in case of drop-ins adapter.
