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Products >> All Products In Focus: RF Lenses Review- Part7

Lens Review: RF100-500mm f/4.5-7.1L IS USM in Bird Photography

Bird photography is often considered to be the domain of the super telephoto prime lenses, but with its excellent image quality, zoom capabilities in a light and compact body, and up to five stops’ in-lens image stabilisation (up to six stops when used with the EOS R5 or EOS R6), a super telephoto zoom like the RF100-500mm f/4.5-7.1L IS USM has its advantages in this genre, too. Professional bird photographer Gaku Totsuka shares his experience and tells us why you might even consider it as a sub-lens to your existing fast super telephoto prime lens. (Reported by: Gaku Tozuka, Digital Camera Magazine)


An excellent super telephoto zoom equipped with powerful image stabilisation

First impressions

The RF100-500mm f/4.5-7.1L IS USM adds a telephoto zoom lens to Canon’s RF mount lineup, much like what the EF100-400mm f/4.5-5.6L IS II USM was to the EF lens lineup. It has the iconic white-coloured body of Canon’s telephoto L lenses, but this time, the lens hood is white too, giving the feel of a whole new Canon.

The lens has a filter diameter of 77mm, the same as its EF lens counterpart. The reach has been extended to 500mm from 400mm. The variable maximum aperture of f/4.5 to f/7.1 means that you will probably have to bump up the ISO speed to increase the shutter speed, but with the EOS R5 and EOS R6,  both of which I shot with, high ISO speed noise was not an issue.

Excellent image quality

The lens construction includes the special Air Sphere Coating (ASC), one Super UD lens, and six UD lens elements. These effectively correct colour bleeding from the image centre all the way to the edges, and you really feel the excellent image quality.

EOS R5/ FL: 500mm/ Flexible-priority AE mode (f/10, 1/4,000 sec, EV ±0)/ ISO 500/ WB: Auto

You usually need a focal length of at least 500mm to photograph wild birds, but when capturing a flock of them in flight, like the black-winged stilts in this shot, it is easier to get a balanced composition using a zoom lens compared to a prime lens.

EOS R5/ FL: 800mm equivalent (1.6x crop mode)/ Flexible-priority AE mode (f/8, 1/125 sec, EV ±0)/ ISO 2,500/ WB: Auto

This ruddy kingfisher doesn’t quite stand out in the dark forest. I didn’t have time to attach an extender, so I used the 1.6x crop function on the EOS R5. This took the red bird out of its unintended “camouflage” and made it pop against the green.


Key feature #1: Supports handheld shooting with up to 6 stops’ IS

What stands out the most on the RF100-500mm f/4.5-7.1L IS USM is probably the built-in Optical Image Stabilizer (Optical IS), which reduces camera shake by up to five shutter speed stops’ equivalent on its own (Also see: How are Image Stabilisation Stops Determined?) When paired with the EOS R5 or EOS R6, Optical IS and the camera’s In-Body IS work together (Coordinated Control IS) to achieve an effect of up to six shutter speed stops’ equivalent. There is only one word to describe it: amazing.

Preventing camera shake is an inseparable part of shooting at super telephoto focal lengths. The lens provides up to six shutter speed stops’ equivalent image stabilisation when paired with the EOS R5 or EOS R6, which makes a difference when especially when shooting handheld in low light conditions. It feels wonderful to look through the electronic viewfinder (EVF) at 500mm and see such a sharp, steady viewfinder image!


Key feature #2: Light, compact, and achieves great balance with the EOS R5 and EOS R6

The lens feels very well balanced when attached to the EOS R5 and EOS R6 bodies, and this, together with the six-stop image stabilisation, increases the freedom to shoot handheld by leaps and bounds.

I found the EF100-400mm f/4.5-5.6L IS II USM rather light, but even with the 100mm increase in focal length range, the RF100-500mm f/4.5-7.1L IS USM is 200g lighter. You don't need a mount adapter to attach the lens to an EOS R system camera, which reduces the total gear weight by even further. It makes a difference, especially when shooting handheld for long periods.


EOS R5/ FL: 500mm/ Flexible-priority AE mode (f/7.1, 1/4,000 sec, EV ±0)/ ISO 2,000/ WB: Auto

This young swallow was flying around rice fields in the rain, looking for food. Such scenes are usually hard to shoot by hand, but achieving this shot was quite a breeze as the RF100-500mm f/4.5-7.1L IS USM is lighter and easier to manoeuvre.

Autofocus: Improvements were larger than expected

The improvements to AF acquisition speed and precision were much larger than I expected, especially in dark conditions. The AF locks onto the subject so fast, you can practically hear it snapping into place (though in reality, focusing is extremely quiet).

EOS R5/ FL: 1,000mm equivalent (with Extender RF 2x) / Flexible-priority AE mode (f/14, 1/2,000 sec, EV ±0)/ ISO 2,500/ WB: Auto

A cattle egret heading towards me, shot at 1,000mm with the help of the Extender RF 2x. Not only was the AF precise and accurate, the image quality was also impeccable.


Key feature #3: Compatibility with extenders


Extender RF1.4x 

- Extends focal length to 420-700mm
- f/8-10

Extender RF 2x

- Extends focal length to 600-1,000mm
- f/11-14

The RF extenders offer an easy way to enjoy the super close point of views of focal lengths as long as 1,000mm (up to 1,600mm if you also use the 1.6x crop mode). I didn’t notice any image quality deterioration whatsoever when using either RF extender, and it is a joy to see such flawless images. Note that the extenders can be attached only when the lens is at 300mm or longer.

EOS R5/ FL: 1,120mm equivalent (with Extender RF 1.4x + 1.6x crop mode) / Flexible-priority AE mode (f/10, 1/30 sec, EV ±0)/ ISO 32,000/ WB: Auto

A collared scops owl with supper in its beak. I used the Extender RF 1.4x, but decided I wanted a closer shot and used the 1.6x crop mode too. The resulting 1,120mm equivalent angle of view captured the owl’s prey clearly, creating more impact. Even at ISO 32,000, the image quality is decent, reflecting the excellent high ISO speed performance of the EOS R5.


Final thoughts

Light, compact, and versatile with excellent performance, even users of the fast super telephoto prime lenses that cost over USD10,000 will probably be tempted to purchase the RF100-500mm f/4.5-7.1L IS USM as a sub-lens. It is good not just for bird photography, but for many other types of subjects including landscape photography. You might even find that it does the same job as a few other lenses! This is certainly one lens that I would recommend.

Attached onto the EOS R5


Lens Hood ET-83F (bundled)


Lens construction

A: Image Stabilizer (IS) unit
C: Super UD lens element
D: UD lens elements


Key specifications
Lens construction: 20 elements in 14 groups
Closest focusing distance: 0.9m (at 100mm)
Minimum aperture: f/32–51
Maximum magnification: 0.33x (at 500mm)
No. of aperture blades: 9 (circular)
Filter diameter: 77mm
Size: φ93.8 x 207.6mm
Weight: approx. 1,370g (not including tripod mount)


Check out some scenes shot on a super telephoto zoom lens and how they were captured in:
Super Telephoto Landscapes: A Mysterious “Cave” in a Moss-Covered Gorge
How I Nailed the Shot: A Tiny Green Bird Among Beautiful Pink Bokeh
How to Photograph Dreamy Images of Decorative Lights
Magical Winterscapes: When Diamond Dust Becomes Sun Pillars


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Digital Camera Magazine

Digital Camera Magazine

A monthly magazine that believes that enjoyment of photography will increase the more one learns about camera functions. It delivers news on the latest cameras and features and regularly introduces various photography techniques.
Published by Impress Corporation

Gaku Tozuka

Gaku Tozuka

Born in 1966 in Aichi, Tozuka developed an interest in photography when he was in the third year of high school, and started to capture natural landscapes as well as wildlife animals. At the age of 20, he became absorbed in photographing wild birds after accidentally capturing a woodpecker in his photo. He has released a large number of works in media such as magazines, bulletins, books, calendars and TV commercials.