I have several Vivitar 285s. They have 4 Auto Flash modes: Yellow, Red, Blue, Purple. Yellow indicates larger apertures, Purple at the other end of the range indicates smaller apertures. E.g., if Yellow indicates f5.6, Purple is around f11. Yellow has the greatest light output, and Purple the least. That has always seemed counterintuitive: seems like full power would call for the smallest aperture, not the largest. What am I missing? Tangential rant: chief among the many things I dislike about digi-cams is the inability, on all but a very few, to strap on a 285 and by-god get some light on the subject.