I would say that the exposure increase for a 2X (focal lenght) extender is 2 stops or 4X (exposure) Francisco 2011/2/28 Jim Brick <jim@xxxxxxxxx> > This has been answered, but as a memory jogger... it is a 2X extender, so > the exposure increase needed is, likewise, 2X. > > > Jim Brick > Sunnyvale, CA > http://www.photomojo.org/vip.swf > > > > On Feb 24, 2011, at 10:15 PM, James wrote: > > how many stops do I adjust for > > >