Features to look for …
Make sure you get what you really need from a wide lens
Lenses that have a built-in lens hood don’t have an attachment thread for fitting screw-in filters or an adaptor ring for square or rectangular filter systems.
Most lenses have built-in autofocus actuators, whereas the Sigma 20mm is driven from the camera body. The Samyang lens only allows manual focus.
Prime or zoom
Prime lenses tend to be smaller and often have wider available apertures, but this isn’t always the case. Many prefer the versatility in composition offered by zoom lenses.
Whether built in or supplied as a separate, detachable item, lens hoods help to combat ghosting and flare, which can be problematic in wide-angle shooting.
Angle of view
It’s worth checking the actual angle of view for a lens (see comparison table, page 100) as it can be different in competing lenses at identical focal lengths, for example the Nikon 14-24mm and Samyang 14mm.
All the Nikon lenses in the group, plus the Tokina lens, feature a weatherseal ring on their mounting plates. This helps to guard against the ingress of dust and moisture.