Archived posting to the Leica Users Group, 2009/12/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Steve, the limiting factor in whether a lens "matches" the M9 offset microlenses and IR filter is the position of its exit pupil which, if I understand correctly, is a virtual point from which the image can be considered to be projected onto the sensor. It has been argued, strongly by Olympus in early digital days, that only lenses designed specially for digital, with exit pupil at infinity, were suited to digital sensors. Long lenses approximate to this anyway and clearly this is an exaggeration since it seems any wide angle lens designed for a reflex camera has a sufficiently distant exit pupil by the time it has been designed to miss the mirror. WA lenses for rangefinder cameras have their exit pupil much closer to the sensor, because they can, and for film this was no problem, coming up with a compromise which suits the M9 to the Leica lenses is what the offset microlenses etc are all about. I am sure the design of the M9 and its software are a good match for the 21mm f2.8 asph. The 21mm f4.5 Zeiss lens OTOH is almost symmetrical, was designed for film without taking these precautions and has very low distortion as a result, but making it unsuited to the digital sensor. I am sure Leica lenses work fine with the M9, with the exception of those published in their literature. Making the offset more would start to make the M9 unsuited to the longer lenses... Some of the Zeiss and Voigtlander Leica mount lenses are unsuited to the M9 but at the beginning Zeiss did not say so. AFAIK nor did Voigtlander. cheers, Frank On 19 Dec, 2009, at 16:51, Steve Barbour wrote: > > On Dec 19, 2009, at 2:46 AM, Frank Dernie wrote: > >> My WATE works fine on the M9. I always assume a lens with an exit pupil >> extremely close to the sensor will be too extreme to be compensated, so >> the 15mm CV almost certainly won't work, though I took a few shots with >> my 12mm and it seems not bad, I preferred uncorrected. Depending on the >> subject the shortcomings may not be noticed at all. It was pretty obvious >> that the Zeiss 21mm f4.5 would be unsuitable for digital > > I'm sorry Frank, I don't follow... why is that and does it apply to the > Leica 21/2.8 Elmarit ASPH on the M9....? > > Does that apply to use with the appropriate external viewfinder? > > > > thanks, Steve