How big do you want to go?

If you don’t need a fast aperture, you can save some weight

One of the biggest considerations when it comes to choosing a telephoto lens, is how much reach you’ll need. Technically, any focal length longer than 50mm on a fullframe camera is considered telephoto. If portraits are your thing, then a flattering look can be achieved with a short or moderate lens in the 70-200mm range. But if small birds are more your bag, then you’ll need all the reach you can get – with 500mm and 600mm lenses being an ideal super-telephoto focal length.

The development of the mirrorless EOS R System has removed some of the barriers for entry with telephoto work. Traditionally, super-tele 600mm lenses have been too expensive, too big and too heavy. But the low-light autofocus capabilities of the new mirrorless R cameras make it possible to work with smaller maximum apertures, and to design more compact and lightweight lenses. Take the professional L-series 600mm f/4 super-telephotos for example. The EF 600mm f/4l IS III USM is 448mm long and weighs 3050g and is almost the same as the RF 600mm F4L IS USM, which is 472mm long and weighs 3090g. But the unique Canon RF 600mm F11 IS STM is just under 270mm long extended and less than 200mm when retracted. Plus it weighs just 225g. But it’s fixed at f/11.

The versatile 100-400mm and 100-500mm zoom lenses offer perhaps the sweet spot of reach and convenience. These lenses are easy to use handheld, particularly the RF 100-500mm F4.5-7.1 L IS USM, which has a 5-stop Image Stabilizer, weighs only 225g and can be paired with the 1.4x or 2x extender.