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Should you buy the new Canon RF 100-500mm L IS USM f/4.5-7.1?

Canon has been criticized by some for not having enough telephoto options early in the RF mirrorless mount’s history, well, they have heard you and they are finally bringing out some telephoto options. Among those options is the apparent successor to the vaunted EF 100-400mm f/4.5-5.6 mark II, the all new RF 100-500mm f/4.5-7.1.

Canon RF 100-500mm L IS USM f/4.5-7.1
Canon RF 100-500mm L IS USM f/4.5-7.1

The new RF lens looks good at first glance, it is 100-500mm which is a nice increase over the older EF lens’s 400mm max reach, however the max aperture drops down to f/7.1 at 500mm. And while Canon has done well to fit the new lens into a compact and light form factor, for some that is irrelevant to the optical facts at hand.

What is wrong with f/7.1?

There is not a whole lot wrong with it in most cases, but in some conditions even outdoors it is going to require users to push their ISO levels higher than before. Higher ISO’s mean lower image quality, and lower image quality begs the obvious question… why did you spend all this money just to get lower image quality? As a wedding photographer I am accustomed to shooting in bad light and I know that the difference between usable and unusable due to high ISO noise is often just 2/3rds of a stop. For instance, it would normally be too much noise to shoot at 3200 ISO with my EOS R, but if I can get down to 2000 ISO, the images are much more usable. Better yet, if I can drop a full stop to 1600 ISO the image quality is quite good. The question is, does f/7.1 force photographers into that “danger zone” at and above 3200 ISO where image quality is heavily impacted by sensor noise and lower dynamic range?

What about the price of the new lens?

Canon RF 100-500mm L IS USM f/4.5-7.1 weather sealing diagram
Canon RF 100-500mm L IS USM f/4.5-7.1 weather sealing diagram

The new lens is also not cheap. It is coming in at a relatively high $2,699. That is $500 USD more than the old EF lens which is highly regarded and has a faster maximum aperture. And while it is true that you get 100mm extra reach with the new lens, the old 100-400mm can be used with a 1.4x TC to give you 560mm @ f/8.  It is a bit of a wash as to whether 560mm @f/8 is better or worse than 500mm @ f/7.1. However, when you consider the fact that you have to use the adapter with the old lens to make it work with the RF mount the idea of upgrading to an actual RF lens starts to make more sense.

Part of what you’re paying for in the new RF 100-500mm is a more extreme optical design. While the old EF 100-400 was no slouch and sports a flourite element and a super UD (Ultra Low Dispersion) element, the new RF 100-500mm has one super UD element and six UD elements. With all those UD elements the RF lens will certainly have very well controlled aberrations and prime like image quality.

What are the options from other manufacturers?

Not surprisingly you can get similar lenses for a lot less money from Sigma and Tamron. While these lenses may not bear the Canon name and reputation for quality, they are usable lenses that give you even more reach and at a larger maximum aperture than the Canon. Sigma has a couple interesting lenses that bear consideration. For instance, the Sigma 60-600mm f/4.5-6.3 has the Canon beat on 3 fronts. It zooms out 40mm wider, zooms in 100mm closer, and has a 1/3rd stop wider maximum aperture. And most importantly to many of you, it retails for $1,759.00, or about a thousand dollars less than the new RF 100-500mm lens.

Will Canon release more RF telephoto lenses soon?

Another question to consider is whether Canon will release more telephotos soon. There are a couple new patents out for RF telephoto zoom lenses. There is a patent for an RF 100-600mm f/4.5-7.1 and an RF 120-700mm f/4.5-8. Both lenses seem like something I and many others would like to see for the RF mount. It is telling as well that the RF 100-600mm f/4.5-7.1 has the same max aperture as the 100-500mm while being 100mm longer. My guess would be a much higher expense and size and weight would be required for that lens which lowers the market appeal and the odds that it will get made. In the end we really don’t know what will be released or when. It could be tomorrow it could be never we really don’t know.

Who is this lens good for?

Canon RF 100-500mm L IS USM f/4.5-7.1?
Canon RF 100-500mm L IS USM f/4.5-7.1?

This lens is great for advanced amateurs and hobbyists who want a good quality lens but also want something they can carry around relatively easily. It is not a cheap lens, so it is not for everyone, but it is a decent value given how much a Canon 500mm prime lens costs. This could also be a great option for pro’s who are travelling and do not want to bring the bigger and heavier prime lenses along with them. A big consideration here is if you’re flying or even going by train do you want to bring a set of super telephoto prime lenses or would you rather just stick this in your carryon bag and be done with it?

What are other reviewers saying?

The reviews on this lens so far have been good. I personally am not a huge fan of the images though. I feel like they’re a bit uninteresting and flat looking. Don’t get me wrong, I think you can get pro quality results with this lens but you probably want to turn up the contrast and clarity a notch or two to really see your images pop.

Of course a cynic might ask what is the point of spending $2,700 on a lens that produces a rather boring image? Well, what is image quality? When it comes to super telephotos the biggest factors aren’t going to be the lens optics as important as they are, but it’s going to be the AF that determines whether your shot is a keeper 99% of the time. It’s the AF that is going to let you track people moving and birds in flight. Sure it is nice to have pristine optics to go along with that but it doesn’t matter how pristine your optics are if the images are out of focus.

With the Dual Nano USM motors this lens has excellent AF capability. Much better than the competition. In a few of the reviews I have seen they’ve shown the lens effortlessly tracking birds in flight.

Would I buy this lens?

If I had the money to spare I would get this lens. No the image doesn’t wow right out of the box, but it’s good enough. My opinion on that also comes from the fact that my other RF lenses are soo good, like the RF 28-70 and RF 70-200. It’s probably unrealistic to expect this lens to hit the level of performance those lenses attain… It is a 5x telephoto zoom after all. The bottom line for me is that the image is clean and usable and the Dual Nano USM AF will ensure the picture is in focus wherever you point it.


Canon RF 100-500mm L IS USM f/4.5-7.1?
Canon RF 100-500mm L IS USM f/4.5-7.1?

I think reviewers are overreacting about the f/7.1 aperture. It just does not bother me that much but based on some reactions it seems Canon might have zigged when they should have zagged. However, and this is a big however, Canon is king of the hill in telephotos. With all the expensive UD and super UD optical elements in this lens it is clear Canon has worked hard to control aberrations with the optical design. This is no doubt a great lens with near prime level image quality and autofocus capability, so if you do not mind the minor shortcoming of f/7.1 it is a superb option for the new RF system and a worthy upgrade to the highly respected EF 100-400mm mark II.


  1. The problem with f-stop outrage is the f-stops only tell you how much light enters a lens. They don’t tell you how much light hits the sensor. The is called t-stops. Some lens lose more light than others depending on the design. Lens should have t-stop numbers on the spec sheets so consumers can make and accurate judgements.

    • Yeah it would be nice I suppose if all the details were sorted properly and the results were meaningful. I just know that transmission is one of those things that is not super well understood even by professional photographers. And if Canon were to do that they might as well publish sharpness metrics, CA, contrast, etc. Which if we’re being honest, they probably should publish. If I buy a car at least they publish specs on the car like how fast it can accelerate, the top speed, gas mileage, etc. The same thing goes for a lot of equipment out there. As far as I know Canon doesn’t even publish the number of colors their cameras can capture, but every TV and monitor company out there is putting out specs on those kinds of things. For an expensive L lens a basic graph of how the lens performs in the box would be nice I would think, even if it’s just theoretical. Something detailing the sharpness characteristics at different focal lengths and apertures as well as a basic rundown of expected CA and corner vignette. But, truth be told, these kinds of things can get pretty complicated and vary greatly based on focus points and scene conditions. That’s why it would have to be pretty generalized and most likely theoretical but even a little something is better than being totally blind. Take the 24-240mm, perhaps a chart showing the sharpness at different focal lengths and apertures just to give people an idea of where to stop down to in order to achieve maximum sharpness at each focal length. Instead of having to guess at it all the time. Like if they wrote in the manual that f/8 is the sharpest aperture at 240mm, then I can target that and work around that setting if sharpness is my goal.


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