I bought another LOMO (Russian design, East German-made) microscope objective. This one, with 10x magnification, did not turn out to be as sharp as the first one I used—the center was sharp, but in first test images, the surrounding areas were…blah. Messed up, stretched, streaky, not very pretty at all.
So I looked through the objective at a printed card (importantly: flat), and I noticed the same thing (sharp center, wavy not-quite-focused edges)—but only when I held the objective more than a few inches from my eye. The default distance for this type of objective is 160mm (about 6”), and my first tests were at that distance.
So I did a test, above, at a shorter distance to the camera sensor (about half that distance). It is…better, but the extreme edges are still a bit soft and odd. Since very few microscope objectives are solid out to the far corners of a full-frame camera, I take this as a win. The only downside is that the magnification is not going to be a full 10x with the shorter back-focus. I can live with that; pretty is job 1. :)
This is a fern leaf, with the spore producing parts (orange) looking intricate and interesting. The depth of field is limited because I did a limited test, “just” 200 images at steps of 5 microns. It took about seven minutes to collect them with the automated WeMacro rail.
I would normally ignore a test sequence, but this one has such a nice look to it. The colors are sensational, and the high contrast of the background creates spaces that I like. It certainly is limited enough that one would not know what it was without prior familiarity with fern reproductive parts. But as art, I love it a lot.