Yes I know I’m doing these lens tests “all wrong”. I’m an engineer; we know about these things. It should be done in a studio with controlled lighting and the camera on a tripod aimed at a lens testing chart which would enable me to carefully count all the lines of resolution from the center to the edges, et cetera.
The only thing is that would be even more boring than what I am doing, both for me and you. Besides, the idea here is to see which lenses of the bunch are capable of producing good pictures under real-world conditions. Anyway, it’s more fun this way.
So we’re up to the Prakticar 70-210mm f4.5 zoom.
This is another ‘automatic only’ lens so it won’t work on the Canon, but it’s no trouble on the Sony. In fact the maximum focal length of 210mm is the same as that of the least expensive Sony zoom I’ve come across, which gives me the opportunity to see if that length is really good enough for my picture purposes – before buying what is a fairly expensive lens (the Sony 55-210mm).
The Prakticar lenses, as I understand things, came about in the late 1970s as Praktica switched to their bayonet ‘PB’ mount but retained the 42mm screw thread mount for lower-end equipment. These were made by more than one company, and the specifications on this example don’t match any that I found in research (all of which say it should be an f4). I suspect it was built by Samyang, however. This lens radiates “lower-end equipment” as it has an over-all too-light and too-cheap feel to it. Its optical performance only reinforces this impression.
That’s about as good as it gets. When you start pushing the limits you find they were already a lot nearer to you than you thought, and certainly nearer than they ought to be.
Okay this lens has low contrast, washed-out colours, poor resolution, and a tendency to exhibit chromatic aberration almost always. Not good. Not good at all. Many, many disappointing pictures. Let’s try harder and see if we can get a decent shot out of it.
We’ve got to try harder!
Much better, but still rather fuzzy even without zooming in. It’s a good thing digital images don’t cost like film!
That is at least not awful. Some post-processing was involved, and no small amount of luck. Considering the build quality, the operation (sloppy focus/zoom ring and difficulty seeing to focus at only f4.5), and the end results this lens gets a rating of “poor”. It’s hard to get even an artistic sort of image from it.
Oh and what about evaluating the zoom length? A bit of a poser considering the low sharpness, but here is what I know to be a downy woodpecker in an aspen tree at about 80 feet away:
The Sony’s 24MP sensor lets us zoom in digitally, which really betrays the lens’s poor resolution:
C’est la vie photographique, non?