----- Original Message ----- From: Mike Johnston Subject: Lens resolution: 35mm vs. medium-format
> > All you have to do is take a look at the published MTFs for 35 mm lenses and > > compare them with those for Medium Format > > > > Again, Don and Pal are correct here. Look at any measure of resolving power > you please--visual lp/mm, MTF, whatever--the smaller the image circle, the > shorter the focal length for the same angle of view, the brighter the lens, > the higher the potential resolution. There isn't a single medium format lens > that can resolve as much on film as the best 35mm lens. From: http://www.hevanet.com/cperez/MF_testing.html Hasselblad 500CM (late 1980's) 80mm f/2.8 Planar CT* <standard lens for 6x6> 68 68 38 f/2.8 60 60 34 f/4 96 96 54 f/5.6 96 107 60 f/8 85 76 60 f/11 68 68 60 f/16 54 48 48 f/22 Pentax 67 - Mirror Lock Up 105mm f/2.4 <standard lens for 6x7> 54 34 19 f/2.4 60 42 19 f/4 76 67 21 f/5.6 67 67 33 f/8 67 67 48 f/11 60 60 60 f/16 48 48 42 f/22 Rodenstock APO Sironar S f/5.6 150mm <standard lens for 4x5> f/11 76 85 43 f/16 76 76 43 f/22 60 60 48 These are actually better resolution numbers than the A series Pentax 50mm f/1.4 got on Fred Wasti's tests, by a significant margin, and (sorry Mike) don't support the assertion that small format lenses are, by definition, better performaers than lenses designed for larger formats. In fact, the opposite seems to be true. I know for a fact that the Hassy 50mm lens is much higher resolution/contrast than anything I have from Pentax. A few years ago, when I was running a custom darkroom, a customer of mine had been hired to photograph an apartment building, perhaps a dozen stories tall. Since he didn't want converging verticals, he photographed it with his Hasselblad and the 50mm lens, from about 3 blocks away, placing the building in the top part of the frame. I ended up printing about a 35mm slice of the negative, enlarging it to 11x14. Every brick was sharply delineated, even the texture in the surface of the bricks was visible. There is no way that lens was deficient compared to a 35mm lens. William Robb
