WIDE-ANGLE WORLD

Get more from wide-angle perspectives by selecting the best lenses for your needs

Wide-angle lenses are generally accepted to be optics with a focal length of less than approximately 40mm, and today they cover everything down to 10mm for APS-C camera models and around 12mm for full-frame sensors. These are the optics of choice for professional landscape and travel photographers, but they find a use in a much greater range of shooting scenarios, from environmental portraiture to sports.

In some respects it is in this range of optics that naming conventions have the most potential to confuse buyers. This is because, as digital photography developed, there was a division between lenses that were needed for wide-angle photography on digital models, and those that were capable of being brought over from film systems.

Due to the smaller sensor area of early digital cameras and the APS-C models available today, the multiplication factor applied to the focal length of mounted lenses means that wider than usual settings are needed to produce truly wide-angle perspectives. The optical designs required to enable this to happen, however, mean that standard full-frame compatible lenses would be prohibitively large, heavy and expensive to manufacture. The solution has been to produce lines of digital-only lenses, with smaller image circles to cover the smaller sensor formats. This enables reduced focal lengths without enormous element diameters.

It is important to recognise which lenses are available for use on both crop-frame and 24x36mm format sensors. While there are now telephoto lenses with smaller image circles, this is usually for weight and portability benefits in mirrorless camera systems.

Other key features of wide-angle lenses are those that address the optical challenges of wide perspectives. These include chemical coatings and glass element designs to reduce edge fringing and geometric distortions, among other things. Designations to look out for are ASPH, which indicates the use of aspherical elements for reduced distortion, and ED or ULD, which denotes special lowdispersion glass. These lens elements are designed to more effectively focus light of different colours at the same point, thereby reducing chromatic aberration.