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.

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.

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 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 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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.


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.

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.

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.

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


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.

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.

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