The first RF-S lenses are annouced. RF-S 18-150 could be the 18-135mm killer lens.

Well, here they are, the first RF-S lenses to go with APSC crop sensors on the new R7 and R10 (and future) mirrorless bodies.

If the RF-S 18-150 is as good as the EF-S 18-135mm offerings have been, I'll be sold.
And unlike EF-S lenses on DSLR, the RF-S lenses will work perfectly on your full frame R in the "crop mode"

Canon Europe;
https://www.canon-europe.com …18-150mm-f3-5-6-3-is-stm/

Gordan Lang already has a hands on (p)review up

Looks nice, but then when I heard f/3.5 - 6.3 max aperture range, I winced...I am constantly wishing my Canon S110 P&S were not handicapped by f/5.9 at the long end, and I got rid of my Canon EFS 18-85mm because of f/3.5 max aperture at the short end.

I have the EF-S 18-135 NanoUSM and it is a really good "all around" lens on the crop cameras. If I were to buy a RF crop, I would probably just keep using it with an adapter.

I'm sort of confused why they are making RF-S lenses compatible with an RF body. If RF-S glass can be used on either mount, why not just stick with RF lenses as opposed to creating a new line? I must be missing something.

EF-S lenses had to be a different mount so they couldn't be mounted on a FF body. The reason is because EF-S lenses had less back-focus, taking advantage of the smaller mirror on an APS-C DSLR. If you put one on a FF body, the mirror would hit the back of the lens when it flipped up.

RF-S lenses don't have that same restriction because there is no mirror in an R body. As I understand it, there's no "RF-S mount", only RF-S lenses. The "-S" simply tells you that the lens has an APS-C size image circle. If you mount an RF-S lens on a FF R body, it will work just fine, but the body will automatically switch to crop mode.

mannetti21 wrote in post #19389402
I'm sort of confused why they are making RF-S lenses compatible with an RF body. If RF-S glass can be used on either mount, why not just stick with RF lenses as opposed to creating a new line? I must be missing something.

My guess is they will be cheaper to manufacture than a full frame RF lens, so more options for people who don't want to spend that much money.

mannetti21 wrote in post #19389402
I'm sort of confused why they are making RF-S lenses compatible with an RF body. If RF-S glass can be used on either mount, why not just stick with RF lenses as opposed to creating a new line? I must be missing something.

Why not?:
- The point of the EF-S and RF-S line is that with the smaller sensor, more affordable lenses can be made by using less glass. So you are simply missing the idea of economy. More glass equals more money. Why pay for glass that is too large when you don't have to?

- This also applies directly to size and weight. More glass = more weight, and size. These lenses are inherently smaller, and lighter. Why carry around more weight when you don't have to?

- In addition, going to the smaller lens elements, means that one can explore more flexibility in design. Many of the most ambitious departures from standard lens design in the last 20 years have been for APS-C sensors.

As to mount compatibility, all R bodies can use RF-S lenses no problem. The full frame R bodies, like R5/R6 etc. will automatically drop down to "crop mode" using only the center area of the sensor that equates to the size of an APS-C sensor as found in R7, R10, 7D2 etc. And of course, just like APS-C DSLR, they can use full frame lenses just as well. You just need to pay more and carry more to use them, and realize that you are only using the center of the image that they can produce.

As mcoren points out, unlike EF-S, there is no RF-S mount. Both the lenses and the bodies are simply RF. It gives us all the advantages of the more compact and affordable lenses without any of the compatibility issues inherent with EF-S.

f.y.i. I have already used EF-S lenses with my R5. Not the best option for most applications, but certainly it works great. I've also used crop mode with full frame lenses (once by accident!)

Comparing the handling of the RF-S 18-150 against the EF-M version, the RF-S zooming feels a little more smooth and firm to me. It's still plastic on plastic, and I hesitate to use the word "dampened", but I definitely like the feel. Maybe mine's just a bit tight because it's brand new? Curious to hear what others think after using it.

thanks for the info. I have to admit that not following M series at all, it never occurred to me that this was essentially an M series lens.
Curious to hear how the M or the new RF compares to the EF-S 18-135.

Very happy with this lens, photo in a shop window