Choosing a lens for birds and wildlife

Birds are small, far away and rarely cooperative. That makes this the most demanding thing most people photograph, and the one where the lens matters most.

Why 300mm equivalent or longer

At 300mm equivalent a small bird at a feeder fills a useful part of the frame. At 400–600mm you can work at the distances wild birds actually keep. Below 300mm you will be cropping so hard that resolution becomes the limit.

This is the case where a smaller sensor helps. The 2× crop of Micro Four Thirds turns a 300mm lens into 600mm equivalent at a fraction of the weight of a full-frame 600mm. Filter with 35mm-equivalent values on to compare fairly.

Autofocus is not optional

Manual focus on a moving bird does not work. Every lens in this list has autofocus, but speed varies enormously — older screw-drive designs and adapted lenses will frustrate you regardless of their optics.

What you will actually carry

A 150-600mm zoom weighs around 2kg; a professional 600mm prime is closer to 3kg and costs as much as a car. Most people are better served by a stabilised telephoto zoom they will carry than a faster prime they will leave at home. Weight is a filter here for a reason.