The RF 35mm f1.8 Macro IS STM was one of the first lenses released with the new Canon RF full frame mirrorless mount towards the end of 2018.
So there are plenty of reviews of the lens available online.
This is a brief summary of my user experience with the lens over the last several weeks.
The 35mm focal length on a 43mm (full frame) sensor has long been a favourite for documentary, street and general photography.
With judicious use of the user’s two foot zoom the moderately wide angle of view given by this lens is very versatile.
There has long been a 35mm f2.0 in Canon’s EF catalogue. I used one for many years in the film days. It was sharp over most of the frame but soft in the corners.
The new version improves on the previous one in every way and adds half macro capability into the bargain.
Indeed, I find the RF 35mm f1.8 close to perfect in most respects.
It is compact, moderately priced, optically and mechanically excellent.
Physical
There are AF/MF and Stabiliser switches on the left side of the barrel.
There is a focus ring mid barrel and a clicky function ring towards the front.
The lens does not have an [L] designation and is not weather sealed.
Filter size is 52mm.
No lens hood is provided and there is no bayonet mount for a traditional lens hood. This may be because of the focus mechanism, see below.
A screw in lens hood is available. Mine is held up in the Covid19 mess so I will report on this later.
This lens’ party trick is its ability to focus very close, right down to 1:2 magnification.
Most lenses these days focus using an inner element or small group which can be driven very quickly by the AF motor.
But this one focusses by moving the entire front optical assembly, which I have read involves the front 9 of the total 11 elements.
This enables very close focussing but involves moving a fair bit of glass every time so absolute AF speed is not quite as fast as many other current optics.
In addition AF is not silent but can easily be heard if one is close to the lens.
In practice this is really not an issue as the front element moves only 1.5mm when focussing from infinity down to one meter. But when focussed at the closest possible distance the front element moves forward 18mm.
The effective focal length increases considerably as the lens focusses to its closest point. At a wild guess it looks to me like it gets to about 50mm effective.
Focus accuracy using AF single on the EOS R is close to perfect with a very low rate of off-focus frames.
On the EOS R the lens will focus accurately in near darkness without the AF assist lamp.
The lens is stabilised and in typical Canon fashion the stabiliser works very well, permitting lower shutter speeds than would otherwise be possible.
Optical
On my test chart the lens delivers excellent sharpness right into the corners straight from f1.8. There is only slight improvement as the aperture is closed down.
If depth of field is not an issue the lens can be used with confidence from f1.8.
There is mild distortion and color fringing with some subjects. These are easily corrected if required in an image editor with the appropriate profile enabled.
Peripheral shading is obvious at f1.8, becoming less so as the aperture is closed down but is correctable with a lens profile if desired.
The lens is not unduly susceptible to flare from bright light sources in or outside the image frame.
I do not test for coma but others have done so and report that it is apparent at the widest apertures.
Recommendation
The RF 35mm f1.8 reliably delivers excellent results on the EOS R or RP.
It is optically almost perfect.
There could be a few minor quibbles to do with the AF operation but in use I do not notice these at all.
Highly recommended.