In this post I’ll be reviewing the new Canon RF 10-20mm f/4 L IS STM made for Canon RF mount cameras like the EOS R5 that I’ll be using to test the lens with.
The first thing to notice about this lens compared to other ultra-wide-angle lenses of the past is that it is much smaller and lighter than those older lenses. Of course, I am only talking about lenses that go wider than 15-16mm. Specifically think of the Sigma 12-24mm f/4 Art and the Canon EF 11-24mm f/4 L USM.
Both of those lenses are great performers, but the RF 10-20mm beats them hands down on size and weight. The tradeoff is that the RF 10-20mm f/4 L has distortion which needs to be digitally corrected. However, even with the distortion, the RF 10-20mm f/4 L is still about the same sharpness in the corners of the image at 10mm.
In the image above shot at 20mm, you can see that this lens piles the resolution on. It looks sharp corner to corner on the EOS R5. For shooting panoramas at 20mm, this lens renders a ton of detail which would make stitching together multiple shots a real treat. I haven’t measured the sharpness of my lenses, but simply looking at the photos from this lens it is L quality from a resolution standpoint.
Another benefit of this lens is the enhanced stabilization. It’s very easy to get long exposure night photos with this lens. The stabilization enhancements are advertised as great for video, but I found that the still image performance was also excellent.
The above exposure was taken at .7s, the lens has no problem with this when mounted on the EOS R5. Overall, I found that the RF 10-20mm f/4 L consistently delivered sharp images at lower shutter speeds than the RF 28-70mm f/2 L did. So, despite the f/4 aperture, the lens is a formidable and powerful low light performer on Canon’s IBIS enabled bodies such as the R5.
The overall performance of the lens is very good in all lighting conditions. The lens may even surpass such high-end options like the RF 28-70mm f/2 L in some ways. Ultimately, the RF 28-70mm f/2 L is probably superior overall as it can be used without corrections, and it has amazing color rendering… While this RF 10-20mm f/4 L may not have the cachet and fine rendering ability of the 28-70mm f/2 L, it delivers a very technically accurate looking image which looks great at such a wide angle.
Overall, it’s a lens that delivers on all levels and in all conditions.
The lens is very resistant to flares and other aberrations, even with the full unobstructed view of the sun in frame. However, at 20mm I did notice some green flaring on some shots in night photos with lights that were more centralized in the frame.
Overall, I think this lens is worth the money if you can afford the price tag. If you are struggling to justify the price for your photography, I would say, figure out how to justify the price. If you absolutely have to find something cheaper the cheapest good quality option is the Sigma 12-24mm f/4 Art. I had that lens for a while, and it is a solid lens.
I personally am happy with it because I really value the stabilization capability and overall clean and sharp look that it brings to the table. I have to give it a solid 4.5 out of 5.
While I’m sure some very particular photographers will be annoyed or displeased with the amount of digital correction required at 10mm. It may not be an absolutely perfect lens, but for what it can do, I think it is worth the price.
Sample Gallery
