What to look for...
FOR TRACK AND FIELD, AS WELL AS OTHER SPORTING EVENTS, HERE ARE A FEW FACTORS TO CONSIDER
All the lenses in the group have a weather seal ring on the mounting plate, and some have additional seals around joints and switches.
This enables a better balance for heavy lenses when placed on a tripod or monopod, especially during portrait-orientation (upright) shooting.
Ring-type ultrasonic autofocus systems are typically quick in operation, especially in the type of telephoto lenses on test, where relatively lightweight internal elements are moved to achieve focusing.
For motor sport and other events where you can’t get physically close to whatever you’re shooting, you’ll often find that you need a lens with a focal length considerably longer than 200mm.
ZOOM OR PRIME?
Zoom lenses offer a degree of versatility that’s impossible to get from a fixed focal length lens, while super-telephoto prime lenses also tend to be very expensive.
Optical stabilisation, also called VR (Vibration Reduction) or VC (Vibration Compensation) by manufacturers, can be a massive bonus when using long focal lengths for handheld or monopod-mounted shooting.