Review: Canon RF 28-70mm f/2 L USM mirrorless zoom lens

Built for full-frame Canon mirrorless cameras, the Canon RF 28-70mm f/2.8 L USM boasts a large maximum aperture of f/2 throughout its focal range. So, this zoom lens is an excellent all-rounder that can handle anything from landscapes to portraits. 

But is the Canon RF 28-70mm f/2 L USM worth the upgrade from its relatively inexpensive DSLR counterparts—the Canon EF 24-70mm f/4 L IS USM or Canon EF 24-70mm f/2.8 L USM? 

Photographer Jonas Hanspach ventured out to the Algarve, Portugal, with his Canon EOS R6 and a set of lenses, to put the Canon RF 28-70mm f/2 L USM zoom lens to the test. Could this be the ideal upgrade from his existing setup? Let’s find out. Over to you, Jonas.

Last year, I had the opportunity to compare the Canon RF 24-70mm f/2.8 L IS USM against the Canon EF 24-70mm f/4 L IS USM. It won’t come as a shock that I loved the RF version as it produces crisp, sharp images, while letting in more light with its wider aperture. Great for outdoor and adventure photography. 

On paper, another similar lens to the RF 24-70mm f/2.8 L IS USM is the Canon RF 28-70mm f/2 L USM. Both are standard zoom lenses, designed for use with Canon full-frame mirrorless cameras, and great for portraits, landscapes, travel and weddings.

I don’t shoot weddings, but travel and adventure photography is my bread and butter. I recently traveled to the Algarve, Portugal, and had the opportunity to test the Canon RF 28-70mm f/2 L USM for a week. 

When I’m in the field, I dislike having to change lenses because it disrupts my flow and can lead to missed moments. So I mainly wanted to know if this single lens, with its f/2 aperture, can replace multiple lenses in my kit bag.

Jonas’ current setup

My usual setup includes the Canon EF 24mm f/2.8 IS USM , Sigma 35mm f/1.4 DG HSM EF and Canon EF 50mm f/1.8 STM prime lenses and the Canon EF 24-70mm f/4L IS USM zoom. But this won’t be an in-depth comparison between the lenses in terms of sharpness or chromatic aberration. 

Before we dive in, I can already tell you that the Canon RF 28-70mm f/2 L USM can easily replace the EF 24mm f/2.8 IS USM and EF 50mm f/1.8 STM lenses. I hardly ever used these tiny pancake lenses because I don’t like lens changes. The differences, compared to the RF 28-70mm f/2 L USM, are very slim. 

The 4mm difference—between the EF 24mm and the widest focal length of the RF 28-70mm lens—won’t matter much to me, especially as I gain an extra 0.8 on the aperture side of things. I will lose 0.2 in aperture with the RF 28-70mm f/2 compared to the 50mm f/1.8, but the Canon EOS R6 is fantastic in low-light environments and the small difference in maximum aperture isn’t worth the time spent changing between lenses in the field.

Overview: Canon RF 28-70mm f/2 L USM

It goes without saying that the Canon RF 28-70mm f/2 L USM is a great lens. It has a fast maximum aperture of f/2, which provides good low-light performance and can create a shallow depth of field. 

The Canon RF 28-70mm f/2 L USM features a broad zoom range and high-quality optics, including ultra-low dispersion and aspherical elements, which help to minimize aberrations and produce sharp images with good color accuracy. 

This lens is robust and weather sealed, which means it’s suitable for outdoor and challenging shooting conditions. But it’s also a heavy beast, weighing 1,430g [50oz]. This is only about 200g shy of the other four lenses combined. So, if you need the lightest possible kit, the Canon RF 28-70mm f/2 L USM might not be the best choice for you. 

But let’s take a step back. Think about why you would actually use this lens. I had two specific requirements. I need it to take sharp and clean landscapes and adventure photos. And I need it to take decent portrait shots on my adventures. 

So, let’s look at both of these scenarios.

Canon RF 28-70mm f/2 L USM for landscape photography

For landscape photography, I compared the Canon RF 28-70mm f/2 L USM to my EF 24-70mm f/4 L IS USM, which is normally my go-to lens for landscapes. 

Besides the 4mm wider focal length, the main difference between these lenses is—as their names suggest—image stabilization. The EF 24-70mm f/4 L IS USM has image stabilisation while the Canon RF 28-70mm f/2 L USM doesn’t. 

But the lack of image stabilization of the Canon RF 28-70mm f/2 L USM wasn’t a big deal for me. The larger aperture lets in more light, so I was able to increase the shutter speed and shoot handheld.

I did expect to miss the image stabilization while shooting video in Portugal. However, given that the Canon EOS R6 has in-body image stabilization (IBIS)—and the fact that I stabilize most of my footage in post-production anyway—the lens’ lack of image stabilization didn’t bother me for video either. 

Alright, let’s look at some comparison shots. I especially wanted to know how these two lenses perform in low-light conditions so I headed out for a blue-hour shoot at the famous Arco de Albandeira.

These pictures are nothing special, but I really like them for comparison. Looking at the settings, you can see how much of a difference the f/2.0 aperture makes. 

The wider aperture meant I was able to significantly lower the ISO and shutter speed. This was great since it was a bit windy. Even though I had my camera as low as possible on the tripod, the photo taken with the EF 24-70mm f/4 L was less sharp. 

Now, let’s talk about color. Looking at these two, I personally find the image taken with the EF 24-70mm to be more aesthetically pleasing. The purple tint and the smoother water—because of the longer exposure—makes for a calmer picture. But colors are definitely more accurate from the RF 28-70mm. 

I can easily change the tint and softness in the water by using a filter or in post-production. Sharpness and noise are also superior in the left image. So, for me, the RF 28-70mm f/2 L USM is the clear winner in this comparison.

Canon RF 28-70mm f/2 L USM for portraits

On the portrait side of things, I compared the Canon RF 28-70mm f/2.0 L USM to my Sigma 35mm f/1.4 DG HSM ART, which is my usual lens for any kind of portrait shoot.

Similar to the landscape comparison, the portrait on the right—taken with the Sigma lens—has a bit of a warmer purple tint with really soft lighting. I absolutely love it here. You can really tell that the Sigma 35mm f/1.4 DG HSM ART is made for portrait photography. 

Don’t get me wrong, the image on the left—shot with the Canon RF 28-70mm—is still great. It seems a little sharper to me, and I know I could get the same look as the Sigma in the edit, but that’s just more work. You might notice that the depth of field is more shallow in the photo on the left, but that’s because it was shot at 52mm, compared to 35mm on the right. Also, it’s worth considering that I took both these images at f/2. If I’d used the Sigma at f/1.4 instead, the subject in the image on the left would’ve been more isolated. 

Depending on the type of shoot, the Canon RF 28-70mm f/2 L USM can’t replace a portrait powerhouse like my Sigma 35mm f/1.4 DG HSM ART—or something like a Canon RF 50mm f/1.2 L. However, it does come pretty close. 

It’s no surprise that I seldom changed lenses, which made it a more enjoyable shooting experience altogether.

Conclusion

The RF 28-70mm f/2 L USM lens is an incredible—but bulky—all-rounder. I could definitely see it replacing three of the lenses in my kit bag. If you're looking for versatility in framing your shots, and if you’re happy to trade some light-gathering capabilities—compared to a dedicated portrait prime lens—then the Canon RF 28-70mm f/2 L USM is a fantastic choice. 

However, it's important to note that this lens—and generally speaking, zoom lenses—cannot replace all lenses. Each type of lens has its own unique strengths and weaknesses. For example, while the Canon RF 28-70mm f/2 provides a broad zoom range, it may not be wide enough for some landscape or architectural photography. Plus, its maximum aperture of f/2 might not be wide enough for some low-light portrait photography scenarios. 

If you're looking for a lens that provides better low-light performance and a shallower depth of field, the Sigma 35mm f/1.4 DG HSM Art is a better choice. But, overall, I cannot recommend the lens enough. 

Check out Jonas’ Canon RF 24-70mm f/2.8 L IS USM versus Canon EF 24-70mm f/4 L IS USM comparison article and read our guide to switching from primes to zooms for landscapes. Or, discover more camera gear guides on the MPB Content Hub.