Archived posting to the Leica Users Group, 1999/06/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>"Henning J. Wulff" wrote: >> >> >"Henning J. Wulff" wrote: >> >><snip>With the introduction of the >> >> Heliar, conversion of the Contax Hologon to M mount should drop to >>zero, if >> >> everyone is aware of the actual performance/handling factors.><snip> >> > >> >I am interested about what are the draw backs of the Contax conversion are. >> >Mark Rabiner >> >> As stated, f/16 and no metering and a much higher price and equivalent >> optical performance. >> >> * Henning J. Wulff >> >I'm really driving you crazy here and you are one of my favorite posters >but f/16 means what? Not the largest or smallest F stop on which camera? >And the Contax cost more I guess you didn't state that but that should >have been handy in our collective memory bank. >You can meter on the Heliar and not the Contax or the other way around? >I was just figuring there was some physical thing I didn't know about. >Mark Rabiner Sorry Mark if I wasn't clear; I just wanted to post a quick reply. The Hologon lenses are fixed f-stop f/8 lenses, but due to their non-retrofocus and very simple construction, have severe light falloff due to the unmitigated cos 4th law. So you have to use the graduated center filter to get even exposures, which effectively means you are shooting at an effective f/16 all the time (or T-stop, more accurately). The Contax-converted-to-Leica Hologon costs a lot more than the Heliar; up to 6 times as much depending on where you get the lens and the conversion. The Contax mounted on the Leica does not allow metering. The Heliar on the M6 does (probably on the M5 and CL as well). Optical performance of the two lenses is not a lot different, but overall I would give the nod to the Heliar, which is slightly sharper than the Hologon. The Heliar is a fair bit sharper than the old Leica 15 Hologon, but that lens did not focus to infinity, only to the hyperfocal distance, and from there down to 8". Consider in this that I have tried only one sample of each lens. If you have a Contax system, and no Leica M system, the Hologon might make some sense. If you have a Leica-M, getting a converted Contax Hologon for it doesn't, now that you have the option of the Heliar. Hope this helps. * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com