Here are some images of scales from an ermine moth, that I made earlier this year. These images are perhaps of interest because they are at the resolution and magnification limits of what a high end stereomicroscope can manage, noting that I am not a “lens testing” kind of guy (although I am very grateful for the efforts of those who are). All images were taken with an Olympus SZX16 + SDFPLAPO 2x .3 NA objective, a schott darkfield stage (VisiLED), and a Nikon D850 connected to the trinocular port with an LMscope adapter (which has relay optics just over 2x, as best I can tell from measuring magnifications). All images are stacks in zerene, objective centered over the photographic optical path. As I mention below I did correct CAs in photoshop.
This first image is at the maximum magnification, 11.5 zoom setting, which ends up being 47x when measured on the camera sensor:
This next image is at 8x zoom setting, which corresponds to 32x when measured on the camera sensor:
Finally, here is an image at 6.3x zoom, corresponding to 25x at the camera sensor:
The .3 NA of the 2x objective produces decent resolution at intermediate/lower magnifications, but at these higher mags it is really pushing it. While this objective is an impressive / expensive hunk of metal and glass, it is really most useful at intermediate mags, 2.5-5x zoom; a lack of telecentricity and poor corners make it difficult to use at the lowest magnification settings of the microscope, and as shown above the higher mags are pushing into empty mag territory. Also, there is a disappointing amount of CAs despite it being labeled as an apo objective. Here are pixel level crops from the first image showing the CAs before correction in photoshop:
The other objective I have for this system, the .8x .12 NA plan apo, is much better corrected it seems
Cheers,
Stephen
moth scales / stereomicroscope limits
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