Low-cost lens cavalcade #1

And so we begin with the series testing the recently acquired M42 mount lenses. The criteria is simple enough; look for sharpness, contrast, chroma, and the very vague “ease of use”. I will post examples showing the characteristics of each lens, but not all of the pictures that contributed to the evaluation. The order of testing is based on my initial thoughts of expected outcome, starting with the likely lowest-quality lens and working up. There will be an “over-all” rating of each along the lines of “poor, fair, good, very good, and excellent”. I’m only expecting one lens to land in that ultimate category.

The camera is the Sony a6000. It could just as easily be the Canon T100 as either is capable of using the M42 mount lenses. For that matter so is the Pentax K100D, although the low resolution of that camera’s sensor as well as other factors make it a poor choice for this experiment. I am trying to do all the pictures alike, using fixed ISO 400 and aperture preferred metering (setting the f stop on the lens and letting the camera pick the shutter speed) to keep things ‘even’ across all attempts. I have cleaned the lenses, in some cases more than once, looked up such info as I could find about each, and did some preliminary shots to explore any potential operational problems.

The process is to take some “general scene” pictures near and far, as well as specific close-ups to check sharpness especially wide open. As mentioned above, not all images will be used in the reports. Also I must repeat that my eyesight is not the best and I have difficulty focusing, especially close where there is limited depth of field to compensate for inaccuracies.

So here we go with the first lens, the Opticam 135mm f2.8:

Opticam 135mm

What can I say? I couldn’t find any solid information on this lens and I wasn’t expecting much from it. That’s exactly what it delivered, although over-all it turned out to be not the worst of the bunch.

At infinity, stopped down, and still “soft”.
As close as it will go, at first glance it looks okay.
Cropped section of the full-size image above. Even the in-focus points are soft.
Contrast and colour rendition are good, no sign of excessive chroma or flare. It just isn’t as sharp as it could be.
Artistic potential. Might even make a good portrait lens.

I truly expected this lens to be a lot worse than it is. Although I don’t think I’ll be using it much and wouldn’t mind passing it on to someone who would, it still earns a rating of “fair to good”. I’m setting it aside for further testing, including trying it on the Canon and Pentax and, most importantly, comparing it to my other two 135mm M42 lenses.