I got a coin microscope for Christmas, the TOMLOV DM4, which I was planning to use for taking close-up photos of crystals that I grow. It is a budget model, but I think it will work pretty well now that I have it set up. The main challenge was the SD card. The advertisement seems to imply that an SD card is included, but I didn't see one in the package. I eventually found one of my SD cards but then realized it needed a microSD card, not the larger variety. So I bought one, but it didn't work, and eventually I figured out that the microscope only will use SD cards that are 32GB or smaller, which is kind of funny because it is actually challenging to find an SD card less than 64GB at the supermarket. So I made a second trip and was able to find a 32GB SD card on clearance.
A few details of operation are a little confusing, like how to switch between video and photo mode, but I worked it out after a few minutes in the ESL manual. The focuser knobs are pretty straightforward. The base is not especially heavy or stable, so you have to hold everything steady while pressing the "OK" button to take a picture.
I had a few small crystals left over from my last experiment, so I took a few photos as a test:
Epsom Salt Crystal Close-Up 2022-12-29, exhibit A
Epsom Salt Crystal Close-Up 2022-12-29, exhibit B
Epsom Salt Crystal Close-Up 2022-12-29, exhibit C
These are not great photo examples, since they were grown quickly, and also there are a lot of white splotches from where the crystals have started to dehydrate. But I'm hoping to grow some nicer crystals soon using the evaporation method.