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Author Topic: Contax 645 lenses/P25  (Read 13142 times)
BJL
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« Reply #20 on: April 03, 2006, 06:06:32 PM »
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When I said "everything" I was refering to the group of medium format SLR lenses (Zeiss for Hassy and Contax, Fuji, etc.) we had been discussing in the thread.
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Thanks for the clarification.

The current 40lp/mm probably fits about right with the 6.8 micron pixel spacing of the latest MF sensors, but maybe it will soon time for Zeiss to go to 60lp/mm in their MTF graphs, as Schneider and Rodenstock already do for their "digital MF" lenses, to keep up with the rumored step to roughly 5 micron spacing in a year or two.

Does anyone know where to get comparable MTF graphs for the Fuji lenses for the Hasselblad H series, or the Mamiya AF lenses, or even the Zeiss-Contax 645AF lenses?

One other thought; I read somewhere in the documents for that Sinar digital MF system that some Nikon lenses (usable on the Sinar with an adaptor) have an image circle big enough for medium format sensors. I can easily imagine this being true at least for the reduced 60mm image circle diameter needed for digital MF sensors and with lenses of focal lengths longer than that 60mm diameter, maybe from 85mm up.

For example, the MTF graphs for the Zeiss ZF 85/1.4 (which is basically the Contax manual focus 85/1.4 in Nikon F mount) make it look like a close match to the Zeiss 85/2.8 ZH for Sinar, at least out to 22mm, and the Nikon 85/1.4 is apparently comparable or better than that Contax 85/1.4, so any of those lenses could become interesting medium format digital options if their image circles are large enough.
« Last Edit: April 03, 2006, 06:19:13 PM by BJL » Logged
Let Biogons be Biogons
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« Reply #21 on: April 03, 2006, 10:11:11 PM »
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Does anyone know where to get comparable MTF graphs for the Fuji lenses for the Hasselblad H series, or the Mamiya AF lenses, or even the Zeiss-Contax 645AF lenses?
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The Contax 645 MTF's on the Zeiss site.  Look under Historical data sheets, here: [a href=\"http://www.zeiss.com/c12567a8003b58b9/Contents-Frame/8401a54783ed1154c12570f90049667d]http://www.zeiss.com/c12567a8003b58b9/Cont...12570f90049667d[/url]
The Fuji lenses for the H1/H2 are on the Hasselblad site (there is a link to a spec/data sheet for each lens's information page.  I don't believe Mamiya (or Pentax) publishes any MTF's -- at least I haven't seen them yet.


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For example, the MTF graphs for the Zeiss ZF 85/1.4 (which is basically the Contax manual focus 85/1.4 in Nikon F mount) make it look like a close match to the Zeiss 85/2.8 ZH for Sinar, at least out to 22mm, and the Nikon 85/1.4 is apparently comparable or better than that Contax 85/1.4, so any of those lenses could become interesting medium format digital options if their image circles are large enough.
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It does look like the new Zeiss ZF 85mm/1.4 is a refinement of the old Contax RTS 85/1.4 (and not related to the Zeiss's moire sophisticated 85mm/1.4 design for the Contax N (also an improvement on the old RTS design, but in ways not necessarily apparent in the MTF snapshots of performance -- like performance at different focusing distances, etc.).  Unfortunately, Zeiss' data sheets don't have any info about image circles, but I don't believe their image circles are much bigger than what is necessary for 35mm film -- they are, at the very least, limited by the small lens mount diameter of the Nikon F mount.  If any 35mm lenses have a large enough image circle it would be the Contax N lenses which have a huge lens mount diameter and equally huge front lens elements (all designed, in part, to effectively and properly handle the corners of a full frame (35mm) digital sensor -- but I wouldn't bank on them being useful that way either.
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Gary Ferguson
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« Reply #22 on: April 04, 2006, 04:35:08 AM »
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but I don't believe their image circles are much bigger than what is necessary for 35mm film -- they are, at the very least, limited by the small lens mount diameter of the Nikon F mount.

But don't Nikon have a shift lens? That would require a large image circle. The image circle on the Canon Tilt & Shift lenses that I'm more familiar is a little shy of 60mm.
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