keith_w <[EMAIL PROTECTED]> wrote: > Precisely as I had envisioned it, but the delta must be very small, no?
Depends. Small but stil noticeable with SLRs. Can be quite considerable with e.g. rangefinder cameras where wideangles don't need to be retrofocus designs. The 21 mm Biogon I've mentioned elsewhere in this thread sits with its rear element a mere millimeter away from the film. Godfrey was speaking of the 15 mm Heliar which must be similar. When they mounted the original Zeiss Hologon for the M Leicas, they had to limit its focussing range to slightly short of infinity to allow for the shutter curtains to pass between the film and the rear element. In such cases you'll have a considerable difference in frame size between this lens and, say, a 90 mm lens. Ralf -- Ralf R. Radermacher - DL9KCG - Köln/Cologne, Germany private homepage: http://www.fotoralf.de manual cameras and photo galleries - updated Jan. 10, 2005 Contarex - Kiev 60 - Horizon 202 - P6 mount lenses
