e-mail: pcacala@earthlink.net
Midwest Biosurveys, Las Vegas, NV USA
Last Updated: April 22, 2002

*** NOTES ***
* All tests photographed at a 1:40 magnification ratio, on Fujichrome 64T (original type) film.
* Test subject: Grand Canyon National Park USGS topographic map (1 to 1 2/3 stop underexposure from a grey card reading).
* Subjective quality factor style grades are relative, with A+ = best, then B, C, D, and F (worst); differences are significant across full letter grades only (unless a paired comparison was made - as noted). Corner grades are measured at 66% out from center and are less rigorous than center grades. An A+ grade for centers and corners is set to the performance of a 50mm f/2.0 Zuiko Macro at f/8.

A = "Tack sharp" professional grade images with great enlarging or projection capability. Approx. 20x30" print size capability.
B = Very good images that will satisfy all but the most discerning users; projected image quality is indistinguishable from an A grade at normal viewing distances. Approx. 11x17" enlargement capability.
C = "Soft" images that cannot withstand much enlargement - suitable for snapshot quality images (5x7").
D = "Smudged" with obvious image defects in even small degrees of enlargement, not suitable for most users (only 3.5x5").
F = unacceptable image for any type of use, lacks detail, only conveys shapes.

* Evaluations made at 24X projection magnification through a Rollei-Vario-Projar 70-120mm lens at ca. 100 mm focal length.
* Vignetting (a.k.a. light falloff) grades:

A = none
B = noticeable, but minor
C = apparent and intrusive
D = unacceptable.

* Contrast grades:

This subjective grading system ranges from extremely low to extremely high, with moderate as the mid-point. Please do do compare lenses based on contrast. The grading should be used for comparing apertures on the same lens only. Exposure and processing differences between tests, plus the lack of a benchmark standard set of slides, makes comparisons impossible. Likewise, early lens test on an OM-1 had much less rigorous contrast determinations, often consisting of only a single statement for the lens as a whole. Contrast levels are reflected in the SQF grade, which is also based on apparent resolution.

Sorry, but my sampling has ended due to the unavailability of the film I used for testing. My thanks to fellow Zuikoholics for lending me additional lenses and contributing funds to defray expenses! Storage USA and the Athletic Arts Academy (both of Las Vegas) graciously allowed room in their facilities for telephoto lens testing. Bill Rogers Camera and Casey's Cameras (both of Las Vegas) lent some non-Olympus cameras and lenses (as identified in the tests).

The tests have been reproduced here on Zone-10 with permission.