>Sorry if this is a dumb question. >When you get a spec. for a lens, >for example: 24-70mm f3.5/5.6 >I know the f3.5 is the speed of the lens, >but why is the 5.6 listed? Steve, the max effective aperture changes across the zoom range. At 24mm, that's f/3.5, at 70, it's f/5.6, and you have no clear indicator of where you are in between (except the readings you get through your in-camera meter). These lenses were designed for minimum size, maximal profits, and keeping in mind that a huge number of users never take the camera off "auto" in one mode or another. Not a dumb question at all. --- Luis
