BJL, are you sure you understand MTF data? You do realize a wide-angle large format lens is not designed to work wide open? You do understand the difference between an f/8 and f/22 curve, which gives a possible difference in resolving power of 225 l/mm and 82 l/mm based on diffraction.
Yes I understand all of that (except that shorter focal length LF lenses like 90mm are more likely to be used at apertures significantly larger than f/22). My description applied to all the aperture ratio data provided for the Super Angulon, both f/5.6 and f/22. Since you introduced those data, can you point to any choice of aperture ratio where that larger format lens does not have distinctly lower MTF within the 35mm format image circle than the smaller format lens?
Please don't misquote me. I never claimed any format lenses would be "better." I am saying there is not much of a difference.
My mistake: I confused you with the poster Concorde-SST that I was originally responding to, who claimed that
... of course you can get much better lenses than the ones from Contax.
Most large format primes (Schneider+Kreuznach, Rodenstock etc.) are way better - it could be
that there might be an adapter solution for using those lenses on Contax cameras
My posts relate to this claim of advantages to using larger format lenses (like Schneider's) with the heavy "crop" a smaller format body (like a Contax 645) instead of using lenses designed for the smaller format. No disparagement from me of larger format lenses when used with the larger formats and generally lower degrees of enlargement for which they were designed!
My specific claim is that if you compare the lenses of the same focal length over the same image circle size at the same resolution level (l/mm), a lens designed specifically for that image circle will usually have higher MTF than one designed to cover a larger image circle, and thus corrected over a wider angular field of view.
Your chosen LF/35mm format pair corroborates this.
Since MTF graphs are available at the same 20l/mm for Olympus Zuiko Digital FourThirds format lenses (image circle radius about 11mm) and for Schneider view camera lenses, I will compare the three "ZD" primes to Schneider lenses of the same or similar focal length at 20l/mm (lower curves on Schneider graphs, upper curves on Olympus graphs.)
Olympus data available at http://www.olympusamerica.com/e1/sys_lens_spec.asp
I) Olympus Zuiko Digital f=50 f/2; Schneider Super-angulon f=47 f/5.6
The smaller format lens has MTF at f/8 nearly a flat line 85% across the field, and wide open at f/2, MTF is about 80% across the image circle (i.e. out to radius 11mm).
The larger format lens has MTF at f/5.6 of 80% on axis, down to 40% to radius 11mm; at f/22, MTF is 70% on axis and falls to between 40% and 60% within radius 11mm.
Or compare that same Schneider lens to the Olympus 14-54 mid-priced zoom lens
at 54mm: it has MTF at either f/8 or wide open f/3.5 of about 90% at the optical axis and above 80% out to radius 11mm.
II) Olympus Zuiko Digital 150mm f/2, Schneider APO-Symmar "L" 150mm f/5.6
The smaller format lens stays at about 90% at both f/8 and wide open f/2;
the larger format lens has MTF 70% or under at all three apertures given, f/5.6, f/11, and f/22.
III) Olympus Zuiko Digital 300mm f/2.8, Schneider APO-Symmar "L" 300mm f/5.6.
Much as in the previous case.
In fact, in these pairings, the smaller format lens has similar or better MTF at 60l/mm to what the larger format lens has at 20lp/mm.
The few cases I can find of "not much difference" is comparing the Schneider Digitars to Olympus Zuiko Digitals. In particular, the Digitar f=47, f/5.6 (40mm image circle radius, or just enough for 6x6 medium format) and Olympus f=50mm f/2 macro have quite close MTF at the one common resolution level of 20lp/mm, a good 80-85%. The Digitar f=150mm, f/5.6 (75mm image circle radius) is also fairly close to the ZD f=150, f/2. But those Digitars do have the design advantage of far smaller maximum apertures than the Zuiko Digitals.