Low-cost lens cavalcade #7

A new year and a ‘new’ lens. This time it’s the Vivitar 24mm f2.8:

Uh oh, it has fungus.

Yes it has fungus. That’s worrying but it isn’t on the glass and there’s no sign of it affecting the images. Yet. Someone skilled with lenses could no doubt take this apart and clean it up quite easily. That someone is not me. I’ve made some recent ventures in lens repairing and … best if I just leave this one alone.

This lens gets some ‘extra’ display shots here because it has some curious ‘extra’ controls which I can not figure out how they function. On the bottom is this tab with markings that doesn’t move even when you push the metal button in:

What is this for? How is it used?

And then the aperture ring has an ‘extra’ set of markings mirroring the f stops but all in green:

Probably some kind of camera-specific auto aperture control.

This is one of those lenses with the tiny button on the back that needs to be pushed in to get it to shift to ‘manual’ if you don’t have it screwed in to the right kind of camera body. (I think this is the Pentax ‘SE’ edition of the M42 mount.) I got it shifted (which means it can also work on the Canon, by the way) and took some shots.

Wide-angle it is even on a cropped sensor camera.

Oh look: I finally got the spots off the sensor! For now anyway. Speaking of it being wide-angle:

The mighty Nissan. This close you can just see some distortion.

Colours are spot-on and contrast is good with no sign of chromatic aberration. Let’s see how sharp it is:

Wild rose full size.
Cropped segment of the full image. This lens focuses to 9″!

That is a very sharp lens. The biggest problem I had was not being able to see well enough to focus at very close distances where depth of field dwindles at f2.8 – even on a 24mm lens.

To ‘correct’ this shot I would have had to adjust the trailer.

Despite the fungus this lens gets a ‘very good’ rating. If put up against the Super Takumar 28mm you would be hard-pressed to tell the difference. The only things against it are that I rarely use such wide-angle lenses and it has that ‘extra’ control function. Neither of those are a fault with the lens. I think this may be good for landscape shots if the 50cm of snow ever melts around here. Hey it warmed up above zero Fahrenheit for the first time in many days! Maybe there will be a Spring.

Spring? Not yet.

In other news it will be a few more weeks before my wife will return, unless they cancel that flight on her as well. Meanwhile I’ve got more medical tests to take, and the temperature is supposed to go down yet again. With more snow. No, we’re not quite to Spring.

Low-cost lens cavalcade #4

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.

A zoom lens for the Praktica.

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.

Ordinary shot of an ordinary Xterra. Ordinary quality.

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.

This should be a good shot, but when you look closer …
… it’s blurry.

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.

Another ‘ordinary’ shot.

We’ve got to try harder!

Close-up achieved.

Much better, but still rather fuzzy even without zooming in. It’s a good thing digital images don’t cost like film!

Back of the bird. (Black-capped chickadee.)

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:

Can’t make it out and it’s not that far off.

The Sony’s 24MP sensor lets us zoom in digitally, which really betrays the lens’s poor resolution:

If you didn’t know you couldn’t tell.

C’est la vie photographique, non?