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We Review the Canon RF 100-300mm f/2.8L IS USM Lens

We Review the Canon RF 100-300mm f/2.8L IS USM Lens

I got an opportunity to use the brand-new Canon RF 100-300mm f/2.8L IS USM zoom lens. This expensive and large zoom lens with a large aperture is even more amazing than I initially expected. In this article, I share my experience and thoughts on this lens from real-world use.

When Canon Netherlands offered me a RF 100-300mm f/2.8L IS USM for a review, I couldn’t say no. This expensive zoom lens with a fixed f/2.8 aperture offers 100mm additional focal length over 70-200mm zoom lenses. It makes it much more versatile compared to the 300mm fixed focal length. It can be combined with the RF extenders as well, offering a way to extend the focal range into the realm of real super tele.

Until now Canon only offered the 200-400mm zoom lens, with a fixed aperture of f/4 and a built-in extender. This new RF 100-300mm lens is one stop more light sensitive, which is perfect for low-light situations. The downside is the lack of a built-in extender. On the other hand, omitting the built-in extender allows for a much more compact and lightweight design.

The amazing Canon RF 100-300mm f/2.8L IS USM on a Canon EOS R5 mirrorless camera.

How It Looks and Feels

Because of the f/2.8 aperture, the RF 100-300mm f/2.8L IS USM lens looks quite similar to the 300mm f/2.8 prime lens. The RF 100-300mm has a length of 323 mm and a diameter of 128 mm. It weighs 2.65 kilograms. As a reference, the EF 300mm f/2.8L II IS USM is 248 mm in length and has a weight of 2.4 kilograms. Canon managed to keep the weight almost the same, although the lens is a few centimeters larger.

It's an impressive sight, such a large white lens. Although it has a good reason for being white, it also stands out.

The minimum focus distance is 1.8 meters. It allows a magnification of 0.16x. The stabilization is rated for 5.5 stops or 6 stops in combination with an IBIS system. Just like most other lens stabilization systems, it offers three modes: one in two directions for general purposes, one in the vertical orientation for panning, and a third mode that only activates the stabilization during exposure, which is perfect for erratic subjects.

The controls on the RF 100-300mm f/2.8L IS USM.

The lens also offers a focus limiter that reduces the minimum focus distance to 6 meters for faster focusing. You can also use a focus preset, activated by a button next to the lens mount. This big white lens has a control ring, something that is missing on the big white RF primes, and there are four focus lock buttons.

The tripod collar cannot be removed. It has a bit of padding on the top of the foot, giving it more grip if you use it as a handle. It is possible to attach a strap to the tripod collar. The tripod collar can be rotated 360 degrees, and clicks at 0, 90, and 180 degrees.

The tripod collar in more detail. Too bad there is no Arca Swiss connection built in.

The zoom ring is large and is located in a good position on the lens barrel. The focus ring is much smaller and closer to the camera body. For using the control ring, you need to reach farther forward. The focus lock buttons are even farther away. If the lens is used handheld, the control ring and focus lock buttons are almost impossible to reach without losing balance.

Real-World Use of the RF 100-300mm f/2.8L IS USM

Although the lens is big and relatively heavy, it can be used handheld without a lot of problems. If you hold it in position for a prolonged amount of time, it becomes heavy, though. A monopod makes use of this lens for a longer period much easier. But it is even better when using a sturdy ball head. Keep in mind, due to the height of the tripod collar, the weight of the lens sits high above the ball head. A gimbal head prevents this unbalance and makes the use of the RF 100-300mm much more convenient on a tripod.

Using the lens handheld is no problem, even with the RF 2.0 extender, as demonstrated by my girlfriend.

The wide zoom ring makes it easy to grab it while holding the eye to the viewfinder. Also, the focus ring can be operated by thumb while holding your hand on the zoom ring or while supporting the lens when used handheld. I found the travel distance of the zoom ring a bit too long, but that can be a matter of getting used to.

The locations of the control ring and the focus lock buttons are quite difficult to reach. Especially when used handheld, these controls are nearly impossible to use without losing balance. If the lens is set on a tripod, it becomes much easier, although the length of the lens forces you to reach far forward.

For the best balance while holding the lens handheld, avoid using the control ring and focus lock buttons.

The RF 100-300mm f/2.8L IS USM focuses extremely fast. I believe the limiting factor will be the camera itself on most occasions. I never felt the need for using the focus limiter.

Blue heron while hunting. I could zoom out, which was great. (EOS R5, RF 100-300mm + RF 2.0x extender, 328mm, ISO 320, f/6.3,1/400 s, shot with gimbal head)

Image Quality and Speed

Since I don’t have an EF 300mm f/2.8L II IS USM prime myself, it is difficult to compare the image quality. However, what I’ve noticed is the almost perfect image quality. There is no noticeable chromatic aberration or vignetting. The lens does produce a bit of flare when photographing a scene with strong light sources in the frame or just outside the frame, but it’s nothing to be concerned about.

A 100% crop of a siberian chipmunk, unedited. (EOS R5, RF100-300mm, 300mm, handheld)

Thee lens hood prevents flares, unless you get the light source directly in the frame. (EOS R5 with RF100-300mm, 239mm, ISO 200, f/8, 1/100 s, shot from tripod)

Using the lens at 300mm focal length with an aperture of f/2.8 offers beautiful bokeh. Looking at highlights in the background shows nice bokeh rings without any onion ring effects.

This is how the bokeh looks at 300mm at f/2.8.

The RF 100-300mm f/2.8L IS USM is incredibly fast when focusing. The two nano USM motors are also silent, which is a benefit if the lens is used in an environment where any noise is unwanted. There was not one situation where focusing was a problem, although I haven't used the lens under the most extreme conditions. I'm convinced the autofocus ability of a camera will be the limiting factor in most situations.

Shooting action is no problem whatsoever. (EOS R5 with RF 100-300mm at 100mm, ISO 1,250, f/3.2, 1/1,000 s, handheld)

Using Extenders

The RF 100-300mm f/2.8L IS USM can be combined with the RF 1.4x and RF 2x extenders. This offers a great range of available focal lengths. You can transfer the lens into a 140-420mm f/4 lens, or a 200-600mm f/5.6 lens. As expected, the RF 2x extender has some effects on the overall sharpness of the image. There is some evident of chromatic aberration also. Still, the results are very good. The RF 1.4x extender shows no noticeable image degradation in real-world use.

Combine the lens with extenders for more flexibility.

The Great Spotted Woodpecker. (EOS R5 with RF100-300mm + RF 1.4 extender, 420mm, ISO 6,400, f/4.5, 1/500 s, shot with gimbal head)

Macro With the RF 100-300mm f/2.8L IS USM

A green tree frog, enjoying the warm sun. (EOS R5 with RF100-300mm, 300mm, ISO 100, f/2.8, 1/320 s, handheld)

When combined with an extender, the magnification increases as well. The RF 1.4x extender will give a magnification of 0.22x. It becomes 0.31x with the RF 2x extender.

A dragonfly called the Broad-Bodied Chaser just before landing. An extender increased the magnification of the lens, while allowing enough distance. (EOS R5 with RF100-300mm + RF 1.4x extender, 420mm, ISO 1,250, f/4.5, 1/2,500 s, handheld)

What Is Missing?

When the lens was announced, the first complaints were about the lack of a built-in extender, like the one in the EF 200-400mm f/4L IS USM lens. Another thing that is missing is a drop-in filter.

The crossing of a red squirrel captured thanks to the ability to zoom out. (EOS R5 with RF100-300mm+ RF 1.4x extender, 201mm, ISO 3,200, f/4.5, 1/1,600 s, shot with gimbal head)

Canon made a careful decision to leave both out. This made it possible to keep the size and weight within reasonable limits. For some, this may be a downside, but the benefits of being able to handhold the lens much more easily must be considered as well.

Leaving the drop-in filters out will force you to buy the extremely large and rare 112mm filters. If you’re thinking about using filters, this may be not the ideal lens.

Landscape photography is perfectly possible thanks to the great zoom range. Often, you don't need the wide aperture. If you like using filters, this lens might be the wrong choice. (EOS R5 with RF100-300mm, 300mm, ISO 100, f/8, 1/15 s, shot with tripod)


I was a bit worried about using this lens due to its size and weight. I was exciting at the same time since the aperture of f/2.8 makes it possible to shoot under less ideal light situations. I asked Canon Netherlands to send me the extenders as well, which they kindly did.

Using the RF 100-300mm f/2.8L IS USM was a great experience. The lens handles very well handheld, and with the right strap, it’s easy to take it on a walk. Yes, it is heavy, but not much more than a bag containing two telephoto lenses.

Siberian chipmunk and wonderful bokeh. (EOS R5 with RF100-300mm + RF 2x extender, 600mm, ISO 4,000, f/6.3, 1/800 s handheld)

This Siberian Chipmunk didn't like to be photographed, or so it seemed. (EOS R5 with RF100-300mm + RF 2x extender, 600mm, ISO 2,500, f/6.3, 1/800 s, handheld)

The focal range gives a bit more reach compared to the 200mm, which is more common for f/2.8 zoom lenses. The true strength of the lens becomes apparent when it is combined with extenders. It offers a maximum focal length of 300mm at f/2.8, 420mm at f/4, or 600mm at f/5.6. On top of that, you have the zoom ability. If your subject gets too close, just zoom out.

A blue herron playing with a little mouse. You could call it the catch of the day. (EOS R5 with RF100-300mm + RF 2x extender, 600mm, ISO 6,400, f/6.3, 1/1,000 s, shot with gimbal head)

Just a rabbit somewhere between the grass. (EOS R5 with RF 100-300mm + RF 2x extender, 600mm, ISO 320, f/5.6, 1/640 s, handheld)

In short, the RF 100-300mm f/2.8L IS USM combined with the RF 1.4x and RF 2x extenders is the perfect alternative to a couple of big white primes. This makes the price of the lens more reasonable.

There one downside is the position of the control ring and the focus lock buttons. These are not in the ideal position for easy use. You must reach too far to use them.

A red squirrel in the sunlight (EOS R5 with RF100-300L + RF 2.0 extender, 600mm, ISO 1,600, f/6.3, 1/1000s, handheld)

What I Like

  • Ability to zoom
  • Aperture f/2.8 over the complete zoom range
  • Weight within reasonable limits
  • Image quality, even when combined with extenders
  • Perfectly usable handheld
  • Autofocus speed

What I Don’t Like

  • Zooming makes a bit too much noise
  • Position control ring and focus lock buttons
  • Tripod color still lacks a built-in Arca Swiss mount
  • No drop-in filter
  • No Arca-Swiss compatible tripod Collar (still not, why Canon?)
  • Expensive

A common wood pigeon in the evening. (EOS R5 with RF 100-300mm + RF 2x extender, 600mm, ISO 400, f/5.6, 1/1,600 s, handheld)


If you are looking for a more affordable alternative, you will end up with an RF 70-200mm f/2.8L IS USM or an RF 100-500mm f/4.5-7.1L IS USM zoom lens. Both are incredible lenses, producing amazing images.

Compared to the RF 100-300mm f/2.8L IS USM, these two competitors, if I may call them that, have their strengths and weaknesses. The RF 70-200mm f/2.8L IS USM has the f/2.8 aperture, making it just as sensitive. But you lack the additional 100mm of focal length. The RF 100-500mm f/4.5-7.1L IS USM offers a longer range of focal lengths, but it lacks the light sensitivity. Both are much more compact, making them easier to take with you.

A comparison of the RF 100-300mm f/2.8L IS USM with the RF 70-200mm f/2.8L IS USM (top row) and the RF 100-500mm f/4.5-7.1L IS USM (bottom row).

Unfortunately, Canon didn’t make the RF 70-200mm f/2.8L IS USM compatible with the extenders, while the RF 100-500mm f/4.5-7.1L IS USM is only partly compatible. This limits the flexibility a lot, especially with the compact RF 70-200mm lens.

It means you must have both alternatives to get all the benefits from the RF 100-300mm f/2.8L IS USM, in combination with the extenders, so to speak. But it will save you a lot of money. Whatever the choice you want to make or are forced to make due to the costs, you end up with high-quality lenses that can produce amazing images.

Nando Harmsen's picture

Nando Harmsen is a Dutch photographer that is specialized in wedding and landscape photography. With his roots in the analog photo age he gained an extensive knowledge about photography techniques and equipment, and shares this through his personal blog and many workshops.

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I'm saving up for either a 400mm 2.8 or maybe now this 100-400 2.8. I have plenty of time to think about it because I have about $9,000 more to accumulate in my piggy bank. I do have the version II of the 600mm f/4 which is an amazing piece of kit, but is quite heavy and not something you can hike long distances with or bring to bear quickly for a shot. I tend to use my EF 1-400 Mk II quite a bit, but for many situations (think sunrise or sunset) it is rather slow, and the variable aperture can be a pain. I'm not necessarily zoomed out all the time, so 100-300 would be useful in many situations. Since I shoot a variety of genres, the f/2.8 70-200, 100-300 and 400 prime would all come in handy, inability to afford all of that aside.

You have to consider the price. The RF100-300L is much more expensive compared to the EF100-400L II or the RF100-500L. The portability and more reasonable price of those two has soms consequences. But the narrow aperture can be easily corrected with the ISO value. It's just a two stop difference. Or consider a EF 300mm f/4L prime if the cost of the RF100-300 is an issue.

What type of dog is that? Havanese terrier?

It's a dog that has been rescued from the streets of Barcelona and brought to the Netherlands (through official ways). It's probably a mix of a Catalan shepherd and a Briard

Also, when you say the tripod collar cannot be removed, I assume you can unscrew the foot and replace it with a 3rd party Arca-Swiss compatible version. Why on earth Canon refuses to accept that Arca-Swiss exists is beyond me. Apparently, there are no issues with respect to using an Arca-Swiss compatible dovetail system. Call it Cano-Swiss or Cano-Dove or something, but for the love of all that is holy, Canon, please put an Arca-Swiss Style dovetail foot on your Big Whites, or at least sell them with the screws but no foot for a little less money so we can just get something compatible on our own.

Yes, you can unscrew the foot and replace it if an alternative is available, like a really Right Stuff.

Great review.

Besides, the lens is beyond my needs and my budget. I guess it will have its fans, when I see your gorgeous images.

Thanks Richard. :)

Waaaay waaay way too expensive. It costs as much as a small car here in Australia. Really, it’s a 100-300mm not some exotic ultra telephoto.

I wonder how many private individuals can afford or justify this lens.

Been disappointed with Canon since they came up with the RF system as the prices are just ridiculous.

I’m a fan of Sony’s 200-600mm because it’s a great middle ground and still fast enough and goes to 600mm and great for birds. I’m not a fan of the RF 100-500, even though it’s sharp. The 600 and 800 f11 are just toys and unsuitable for many situations.

I honestly just clicked on this for the dog thumbnail.

That's because it is such a nice dog. Did you know he has its own social media on Facebook and Instagram? Just look at https://www.facebook.com/Brucs.wereld and @brucswereld

I cant imagine who's going to shell out crazy big bucks for this lens. It makes little sense to me. I add a converter to my 70-200 if needed.
I have both a small, light 300 f4, and 300 2.8 and can add a converter. My 400 2.8 completes the very usefull kit.
The 200-400 on the other hand is very tempting.

You're not using RF glass i take it?? You have roughly $22,000 in EF lenses!!!

Thx for the nice review. Which RRS plate are you using? Universal? Any idea if I can pop on a Kirk replacement lens foot with built in Arca plate and if so is the foot connection the same as any of the other Canon lenses? thx!

I used the regular RRS lensplate that I have for my RF100-500L lens.
For this lens I would recommend a replacement foot. although the one I used worked quite well.

Waiting on mine to ship!! What a perfect lens for wildlife like Africa, and Alaska brown bears, It will cut down on the lenses i have to pack on long trips. Can't wait!!