Fast workers
The advantage of fast lenses comes from their very wide maximum apertures. Pound for pound, more light means faster exposures at lower ISOs, which are useful across the board, and the secondary effect of aperture – depth of field – gives photographers creative choices. More light also makes AF more efficient. These benefits can be felt in almost any sphere of photography and across the next few pages we’ll hear from how they help photographers who are working in very different subjects.
But before we get started, it is important to understand just what fast lenses are. This is a slippery term and whether a lens’s maximum aperture defines it as ‘fast’ depends on several factors. It’s also highly relative.
For starters, there’s focal length. A 50mm f/1.8 lens might not be seen as particularly fast by modern standards, but a 135mm f/1.8 lens would be, particularly as that’s about the fastest you can practically go at that focal length. Similarly, a 14-24mm f/2.8 is considered fast for a full-frame zoom, but a prime lens at any of its focal lengths wouldn’t
