Canon RF 15-35mm f/2.8 USM L IS - Review / Test Report
Lens Reviews - Canon EOS (Full Format)

Review by Klaus Schroiff, published March 2020

Introduction

Canon has upped the game compared to their DSLR lineup with pretty much every new lens they released for the EOS R system. They added an IS on the RF 24-70mm f/2.8, released an RF 28-70mm f/2 with a speed never seen before and made the RF 70-200mm f/2.8 shorter than any comparable lens in its class. And in the ultra-wide zoom segment? They are now offering the Canon RF 15-35mm f/2.8 USM L IS - a lens that is wider and adds an IS while still avoiding the bulb-like front element that we've seen in most other modern designs. Unsurprisingly, it's also a pricey lens at 2300USD / 2500EUR. Please note, however, that this is just a little bit more expensive than the EF 16-35mm f/2.8 USM L III at the time of its release and you are getting something extra here. Still, hopefully, Canon is going to offer a more moderately price f/4 variant for the rest of us in the near future.

The RF 15-35mm f/2.8 USM L IS is a big lens with similar dimensions and even a marginally increased weight compared to its EF "predecessor". Unsurprisingly, it follows the usual RF design philosophy. It uses some kind of very high compound material for the body, combined with big rubberized focus- and zoom-rings. At the front, there's also the additional, customizable control ring for those who prefer to have an aperture, ISO or exposure control on the lens. Needless to say, the lens is also dust- and splash-proof. Fluorine coating on the front element helps to repel dust and water as well. However, a slight downside is the extending zoom mechanism. The inner lens tube extends by about a centimeter towards the WIDE end which is a little unusual. A very short, petal-shaped plastic lens hood is part of the package.

The AF is, once again, based on Canon's Nano USM which offers both very fast as well as noiseless AF operations. Focus accuracy is very high at 15mm but it suffers a little beyond when stopped down a bit (residual spherical aberrations). To be fair - in real life, any inaccuracy will usually be hidden within the immense depth-of-field. Manual focusing works "by wire" but other than the lack of a focus distance scale, you won't really notice much of a difference compared to a mechanically coupled focusing system. The IS has a claimed efficiency of up to 5 f-stops. Based on our real-life experience with the lens, we'd say that it's 1-2 f-stops less than that though.

Specifications
Optical construction16 elements in 12 groups inc. 2x UD & 3x aspherical elements
Number of aperture blades9 (rounded)
min. focus distance0.28m (max. magnification ratio 1:4.76)
Dimensions88.5x126.8mm
Weight840g
Filter size82mm
Hoodpetal-shaped (bayonet mount, supplied)
Other featuresweather-sealing, image stabilizer (5 f-stops), additional control ring, fluorine coating