So would you call a 400mm f/2.8 lens wide? Its field of view is only 5 degrees. \:\)

In this case fast refers to the faster shutter speeds available that wouldn't be with smaller apertures. And fast can also refer to the autofocus speed. And I don't know anyone who prefers a lens that takes forever to gain focus. ;\)









It's a Trumpeter Swan. ;\)
[/inside joke]