On Thursday 15 August 2002 11:00, Bill Owens wrote: > Which brings another question to my feeble mind. Would adding an > additional 50mm of extension to a lens that is already extended increase > exposure by one stop, or is this too simple to be feasible? :-) > > Bill > > Bill;
Adding extension by whatever means increases exposure. For example, my vivitar S1 105/2.5 has 100mm of built in extension for 1:1 magnification. As I focus closer the exposure changes, ie f2.5 at infinity 1.5 - 2 stops difference at close focus. I can then add more extension via tubes or bellows or whatever and this would change the exposure again. I've learned to rely on the LX's TTL meter and just compensate for tonal variation. If you use a handheld meter the calculations become a nightmare. HTH Christian - 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 .
