Most telephoto zooms that reach 400mm cost thousands and weigh well over a kilo. The Canon RF 100-400mm F5.6-8 IS USM costs about $650 and weighs around 635 grams. It’s light enough to carry on a hike, cheap enough to buy on a whim, and a lot sharper than the price suggests.

That’s why it became one of Canon’s most popular RF lenses. It’s the default “first long lens” for R50, R10, R8 and R6 Mark II owners who want to try birds, kids’ sports or airshows without committing serious money.

For Nikon Z wildlife shooters, the Nikon Z 180-600mm f/5.6-6.3 VR was the lens that changed the math. Launched in 2023 at about $1,700, it gave affordable 600mm reach with fast autofocus, weather sealing and an internal zoom. A lot of people built their whole bird-photography kit around it, often on a Z8 or Z6III.

Internal zoom means the lens doesn’t get longer as you zoom. The barrel stays the same length from 180mm to 600mm. Balance doesn’t shift, it doesn’t suck dust in, and it sits better on a gimbal head or a monopod.