Canon RF-S lenses explained

Alongside the APS-C format Canon EOS R7 and Canon EOS R10, Canon has announced the first two lenses of a new line-up with the RF-S mount. The launch of any new range of cameras and lenses always raises a few questions, so here’s everything you need to know about Canon RF-S:

What is the Canon RF-S lens mount?

The Canon RF-S lens mount is actually the same as the full-frame Canon RF lens mount but the RF-S lenses produce a smaller image circle than RF lenses. That’s because they’re designed to be used on the new Canon R7 and R10 which have a sub-full-frame image sensor.

What RF-S lenses are there?

So far, Canon has announced two RF-S lenses, the Canon RF-S 18-150mm F3.5-6.3 IS STM and the Canon RF-S 18-45mm F4.5-6.3 IS STM. As they are designed to be used on the company’s new APS-C format EOS R7 and R10, their focal lengths are subject to a 1.6x magnification factor. That means that the RF-S 18-150mm F3.5-6.3 IS STM produces images that are comparable with a 28.8-240mm lens on a full-frame camera while the RF-S 18-45mm F4.5-6.3 IS STM is equivalent to a 28.8-72mm lens.

This means that the RF-S 18-150mm F3.5-6.3 IS STM can be regarded as a travel zoom lens that’s suitable for a wide range of photography while the RF-S 18-45mm F4.5-6.3 IS STM is a small, light ‘walkabout’ optic for everyday photography.

Can I use my Canon RF lenses on the Canon R7 and R10?

Yes, however, because the R7 and R10 have a smaller sensor than Canon’s full-frame R-series cameras, it will look like the lenses are 1.6x longer than they appear on a full-frame camera. This focal length magnification factor means that a Canon RF 70-200mm f4L IS USM, for example, will effectively become a 112-320mm lens, making it even better for picking out distant details. However, it also means that some of the lens’s capability is ‘wasted’ because you’re only using a central section of its image circle and you’re carrying a bigger, heavier lens than an equivalent RF-S lens would be.

Can I use RF-S lenses on a full-frame Canon EOS R system camera?

As well as the R7 and R10 cameras that they are designed for, Canon RF-S lenses are directly compatible with the Canon EOS R6, R5, R3, R and RP. However, these cameras require a firmware update to tell them to crop to the APS-C format when an RF-S lens is mounted. We are told that a firmware update is coming ,but we don’t yet know when it will be available.

Can I use the Canon EOS R7 or Canon EOS R10 with EF and EF-S lenses?

Yes, but you need to use an adaptor to get the EF or EF-S lens to fit on the R mount of the new canon R7 and R10 cameras. Follow the link to read how to use EF and EF-S to RF lens adapters.

Are Canon RF-S lenses as big as RF lenses?

No. Although the lens mount is the same size, the barrel is smaller because the optics inside don’t need to be as big. This means that Canon RF-S lenses should be smaller than comparable Canon RF optics.

• Best Canon RF lenses

Will there be more Canon RF-S lenses?

Canon hasn’t said anything about its future plans for the RF-S lens range, but we can expect more optics to come over the coming months. We’re hoping that Canon will show more commitment to the EF-S mount than it has with the EF-M mount. The EF-M mount is used on Canon’s original range of APS-C format mirrorless cameras such as the Canon EOS M50 Mark II and EOS M6 Mark II.

We’d like to see the RF-S equivalent of 24-70mm (15-43mm) f/2.8 and f/4, 70-200mm (43-125mm) f/2.8 and f/4 lenses, plus some longer zoom lenses for wildlife photography, a few fast primes and a macro lens.

Canon is pitching the R7 as a camera that’s suitable for wildlife and sports photography, so it seems likely that we will get some RF-S lenses that are also designed for the task.