31 and 35mm lenses tested in German magazine

[Arnold Stark]

In the February edition of German ColorFoto (CF) magazine the SMC Pentax-FA 1:1.8 31mm Limited and the SMC Pentax-FA 1:2 35mm AL are tested along with 35mm/f1.4 lenses from Canon, Leica R, Minolta and Zeiss, 35mm/f2 lenses from Canon, Leica R, Minolta and Nikon, and a Zeiss 35mm/f2.8. For the last two years, the CF lens tests have shown a lot of consitency. Unfortunately CF usually tests lenses wide open and two stops down, so it is hard to compare the MTF results of lenses of different maximum aperture. However, this much can be said:

Of the lenses with f=1.8 or 2 maximum aperture, Minolta and the two Pentaxes offer the best image quality with 20 points (out of 30) for sharpness/resolution and 28 points (out of 30) for contrast. Canon is close (19 and 28 points) while Leica (18 and 27) and Nikkor (17 and 27) are defeated. Looking at the MTF curves, the Minolta 35/f2 offers the best performance wide open. However, at f=4 the MTF of the the Pentax 31/f1.8 is by far the best with unusually small fall-off from centre to corner. Light fall-off (vignetting) is relatively well controlled in all lenses (7 points out of 10) except for Leica (5/10). The Leica (6/10), Canon (6/10) and Minolta (7/10) 35/f2s offer slightly less distortion than Pentax (5/10 each) and Nikon (5/10). The Minolta offers excellent centration (? Zentrierung in German) with 20 points out of 20, while Leica (18), Nikon (17), Pentax 31/f1.8 (17), Pentax 35/f2 (16), and Canon (15) offer good to mediocre centration (of the lens elements) only.

BTW: Of the lenses with f1.4 maximum aperture, Canon and Leica are the best, however, at f2.8 the Contax 2.8/35 beats them all.....

Arnold