[EMAIL PROTECTED] writes: << I know this lens uses the diaphragm to keep the constant f/4 aperture and was noticing it looks as though if Pentax would have kept it in the full-open position, it would be a f/2.8-f/4. (Or really close to that) My question is, why did Pentax choose to use the diaphragm to have a constant f/4 lens rather than a f/2.8-f/4, which they could, I think, sold for a higher price, or am I missing something? (Wouldn't be the first time) :-) >>
Gary, If your camera & flash can't do TTL, then the flash needs you to set f5.6 or f8 or f4 on the lens. On a zoom, if you set f4 and zoom in, then the aperture changes to f2.8 but the flash is still set for f4. You get overexposed shots. That's one reason for constant aperture zooms. Regards, Bob S. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
