Informal Lens Tests

by Rod Smith, rodsmith@rodsbooks.com

Last update: 2/25/2005

Photography is my hobby. I own several cameras, most of which use the Pentax K mount, but I've also got a few others, including a Soviet Kristall that uses the Zenit M39 mount. In an effort to determine the quality of various lenses I own, I did a simple and informal test: I loaded a Zenit APk camera with Ilford Pan F+ ISO 50 film, mounted it on a tripod, and shot a test scene with nine lenses. Note that this is a very informal test; I don't present it with any claims of precision or repeatability. The lenses are of varying ages, and I got some of them used, so I can't vouch for their pedigree. It's possible that the focus wasn't perfect on some tests, or that vibrations caused problems. That said, the lenses I tested were:

• A Mir-1 37mm f/2.8 with Zenit M39 mount
• A Tamron 28-70mm f/3.5-4.5 with Adaptall-2 mount
• A Pentax-M 50mm f/1.7 with K-mount
• A Chinon 50mm f/1.9 with K-mount
• An Industar 50mm f/3.5 with Zenit M39 mount
• A Helios 44K-4 58mm f/2.0 with K-mount
• A Tair-11 133mm f/2.8 with Zenit M39 mount
• A Pentax Takumar 135mm f/2.5 with K-mount
• A Tamron 158A 70-210mm f/4-5.6 with Adaptall-2 mount

The Tamrons used Ricoh K-mount adapters and the Zenit M39 lenses used both M39-to-M42 and M42-to-K-mount adapters.

I shot a piece of 8.5"x11" paper with the lens name, slightly off center, for each lens. For the wide angle and normal lenses, I shot at f/5.6, but for the longer lenses, I used f/8 because f/5.6 was just too close to the Tamron's maximum aperture. I let the Zenit APk's exposure meter determine the shutter speed. (The day was mostly clear, but a few stray clouds changed the light slightly during the course of the test.) I tested the Tamron 28-70mm twice, once at 35mm and once at 50mm. I tested the Tamron 70-210mm at 135mm, to compare it directly with the fixed lenses of roughly that length. I moved the camera on its tripod when switching between different classes of lens lengths to approximate the same view for each lens type.

I developed the film myself in Kodak D-76. This was only the second roll of film I've developed myself, and I had problems with the reels on the tank. This resulted in some film buckling that caused crescent-shaped artifacts on some of the frames. I scanned the negatives with a Minolta DiMAGE Scan Elite 5400 at 2700 dpi using VueScan.

I've grouped the results on three sub-pages:

• Wide lenses -- The Mir-1 and Tamron 28-70mm at 35mm
• Normal lenses -- The Pentax, Chinon, Industar, Helios, and Tamron 28-70mm at 50mm
• Long lenses -- The Tair-11, Pentax 135mm, and Tamron 70-210mm at 135mm.

To sum up, the winners in each category were the Mir-1, the Helios-44K-4, and the Pentax Takumar 135mm.

I've also written a page with some informal scanner tests.

If you have problems with or comments about this web page, please e-mail me at rodsmith@rodsbooks.com. Thanks.

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