Items on same line indicate model updates. Different lines indicate varying model levels.
The EOS RF mount was designed for full frame cameras, of which we have six current models right now (one is an astronomical version of an earlier camera). In 2022, Canon expanded that to include crop-sensor cameras, of which we now have two. To some degree, Canon is mimicking their DSLR lineup with most of these cameras: the RP is basically equivalent to the 6D Mark II DSLR, the R5 is an updated variation of the 5D Mark IV DSLR, while the R7 is basically a 90D DSLR replacement.
The R or the RP are now lower-end full frame models; both appeal mostly to budget-conscious consumers, not pros and high-end enthusiasts. The R3, R5, and R7 appeal to different needs of those pros and enthusiasts. Meanwhile, the recently introduced R7 and R10 now bring RF-S into the picture to replace EF-S.
Here's my advice with cameras here in 2022:
- On a strict budget: buy the R7, or possibly the R10. No, the R and RP are no longer price/performance choices I'd make at current pricing.
- Looking for overall excellence: buy the R6 if you don't have a need for lots of pixels or 8K, the R5 otherwise.
- Need fast focus and frame rates: buy the R3 if you can, but the R7 isn't a bad lower price option.
The RF cameras can use EF DSLR lenses via an adapter. Canon actually makes three EF-to-RF adapters: a basic one, one that adds an additional control ring to the lens, and one that allows drop in filters within the adapter. All three adapters work quite well with virtually every EF lens Canon has made, and with most third party EF lenses, too. Note that the R and RP bodies do not have sensor-based image stabilization, so you probably want to stick with EF lenses with IS in them if you purchase those bodies.
Speaking of lenses, the RF native lenses are still a work in progress at the moment, and many of the available lenses are L lenses (high-end). Most full frame buyers with quality in mind are likely going to get the 24-105mm f/4 L IS, or perhaps the 24-70mm f/2.8 L IS for the primary mid-range.
All the f/2.8 zooms are all very good, as are the 50mm and 85mm f/1.2 primes. The 100-500mm f/4-7.1L is a really good telephoto option. I'd suggest R5/R6 users start with the 24-105mm f/4L and supplement with the lenses just mentioned. The 24-100mm f/4 and 100-500mm f/4-7.1L make for a really strong 24-500mm starting kit for full frame.
Buyers of the crop sensor R7 and R10 are currently starved for lenses, as there are only two RF-S lenses so far. The 18-150mm f/3.5-6.3 IS is a decent lens, but we really need more and better choices than Canon has provided so far.
One thing to be aware of is that Canon M and Canon RF mounts aren't compatible in any way. If you're thinking about buying an M camera and an RF camera from Canon, you're going to either need two lens sets (M and RF) or dip heavily in the DSLR EF lenses via mount adapters.
