Longer telephoto reach and wider available apertures both result in larger, heavier lenses. For example, the Nikon 70-200mm f/4 lens only weighs 850g, whereas the Sigma 120-300mm f/2.8 is four times heavier, at an impressive 3.39kg.
The size issue
Constant-aperture telephoto zooms may seem physically quite large, but their overall length typically doesn’t extend at longer zoom settings.
Take the strain
Using a tripod or monopod to support the weight of a big telephoto lens makes for a much more comfortable shooting experience, and helps to fend off camera shake.
Get a head
Gimbal heads enable smooth tilting and panning with a tripod or monopod as they rotate the lens around its centre of gravity. They’re great for air shows and for shooting birds in flight, especially if using heavy lenses.
This can be a problem with very long lenses in tripodmounted shooting. When timing isn’t critical, use the exposure delay mode, featured on most Nikon SLRs.
The ‘effective’ focal length is magnified by 1.5x when using an SLR with an APS-C format sensor. This boosts the apparent reach of telephoto lenses.
For fairly close to midrange shooting, wide-aperture telephoto lenses can give a really tight depth of field, making them useful as portrait lenses.
All Nikon and Sigma lenses here are compatible with their own-brand teleconverters. Tamron recommends Kenko TCs.