The focal length gets shorter. An internal focusing lens is sort of a limited zoom lens.
--graywolf ------------------------------------------------- The optimist's cup is half full, The pessimist's is half empty, The wise man enjoys his drink. ----- Original Message ----- From: Frank Wajer <[EMAIL PROTECTED]> To: pdml <[EMAIL PROTECTED]> Sent: Monday, November 26, 2001 10:28 AM Subject: fov change with IF lenses > Hi, > > with non IF I can calculate the change in field of view (FOV) when > changing focus. > I think the FOV is smaller as you focus closer. > > I noticed that with my 24-90 lens the fov actually gets wider when > focussing closer. This > is an IF lens. The only explanation I have is that f gets smaller when > focussing closer > with IF lenses, but I don;t know how. Anyone have an equation for the f > change? > > > Frank > - > 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 . - 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 .