Canon rumoured to refresh 400mm and 600mm super-telephoto lenses

Canon’s super-telephoto line may be headed for its first real reset in years, and the buying question is immediate: pay flagship money now, or wait for lenses that could build extra reach into the barrel itself. The latest talk points to replacements for the RF 400mm f/2.8L IS USM and RF 600mm f/4L IS USM arriving late in the year, with shipping slipping into 2027, and that timing alone is enough to make wildlife and sports buyers pause.

The current pair is no lightweight stopgap. Canon announced both lenses on April 21, 2021, and described them as optically identical to their EF-mount counterparts, which makes a true RF-generation update look more like a meaningful redesign than a simple mount swap. Canon U.S.A. lists the RF 600mm f/4L IS USM at $14,499.00 and positions it for professional and advanced photographers, while the RF 400mm f/2.8L IS USM is rated for use with Canon RF 1.4x and 2x extenders and up to 5.5 stops of image stabilization correction. The current lenses also remain substantial pieces of kit, weighing 2,890g for the 400mm and 3,090g for the 600mm.

What would change the market is the rumored built-in teleconverter. The expectation is that both replacements would include a 1.4x unit, which would let a photographer toggle between native reach and extended reach without digging an extender out of a bag. For field work, that is not a minor convenience. It is one less accessory to lose, one less seal to break in dust or rain, and one less decision when action shifts from close to far in a matter of seconds.

The rumor mill also keeps circling a 500mm prime, linked to an RF 500mm f/5.6 L IS patent. One description puts the design at 296.6mm, just under 12 inches long, and nearly 40% shorter than the RF 600mm f/4L IS USM. Another comparison says it may be about the same size as the older EF 400mm f/5.6L USM, which would make it a very different proposition from Canon’s current giant whites: less extreme on paper, but potentially much easier to carry, handhold, and travel with.

For buyers, the practical effect is simple. If Canon really is preparing a lighter, more flexible pro telephoto family, used prices for the current RF 400mm and RF 600mm are likely to soften as more shooters wait for the next version. Anyone who needs a lens for the 2026 season still has two proven options on the shelf, but anyone shopping with no deadline now has a reason to hold fire and see how Canon redraws the top end of the lineup.