The lenses tested:
I shot two scenes with each lens: one with the lens focused on a pole that was 1.1 meters from the camera and the other of a building across the street from my apartment that is approximately 30 meters away.
1) My eyesight. At last check I still have 20-20 vision and I tried to focus as critically as possible, however there is still likely to be some variation in the exact point of focus between shots.
2) Lack of an infinity target. Because I was shooting from just outside my front door due to the weather (see #4), there was no good "infinity" target available. Later, as weather and time allow, I hope to re-shoot some of these tests with each lens set to infinity so that I can remove some degree of focus error.
3) Aperture settings. Now that I think about it, I first set the lens to F2.8 and took a shot, rotated the aperture ring to F8 and took another shot, then rotated the aperture ring to F22 and took a third shot. However, on a Kiev, Pentacon 6, or Exakta 66 camera body these lenses usually rely on a quick release of pressure from their aperture control pins when the shutter release button is pushed, which allows the aperture to snap down to the correct size under spring tension. By my simply rotating the aperture ring between shots for this test, there was no quick release of pressure from the control pin, and the size of the aperture could very well be incorrect.
Indeed, as you look at the images, you will see exposure variations across them. Next time I do one of these tests, I'll first set the aperture to F22 and push in the control pin at the back of the lens then quickly release it and let the aperture snap closed. After that I'll mount the lens on the camera and open it up for subsequent shots. This should provide more consistent results.
4) Weather. The weather has been miserable here in Tokyo with one typhoon after another. On the day I shot this test it was overcast and started to rain as I prepared to do the 30 meter test. Still, it wasn't windy and camera shake should not be an issue. In the 30 meter shots I can actually see rain drops falling, but they should not really affect the perceived sharpness of the images for this test. Contrast and color will be slightly affected by the weather conditions but at least it will be consistent for all lenses.
5) No lens hood. I didn't use a hood on any of these lenses since I don't have one hood that will fit all of them. The 90mm Makro-Kilar is especially problematic since I still have no idea what size of attachments will screw into its front threads. It appears to be 64mm, but no one makes anything for a 64m thread.
6) Representative sample. I am using my own equipment for these tests, some purchased new but other pieces purchased used. I do not know the history of the lenses I purchased used, and so some of them may have been disassembled or serviced prior to their coming into my possession. At any rate, the lenses tested here are assumed to be a "representative sample" of what is commonly available. Variations in manufacture among other things may skew the results, and so these test images may or may not accurately reflect what you can expect from a different lens specimen.
All text and images Copyright © 2004 - Kevin Ing