Round 50c piece

Most of my work colleagues, being the young kids they are, have never seen a round 50 cent piece, or even heard of them. It makes me feel a bit old. After all, they haven't been in circulation since 1967. (I've been in circulation a bit longer.)

I came across one the other day in my father-in-law’s old coin collection, and decided to take a photo of it.

To do this, I used a USB microscope, a Celestron Handheld Digital USB Microscope Pro. You can see the setup I used in the photo, with the microscope connected to our work laptop.

I did have some trouble with the photo, because the coin is larger than the field of view of the microscope when it’s on its stand. You can see the setup here, including the image that was too large for the screen.


So, I had to hold the microscope in my hand and hover it above the coin. That meant I couldn’t get a really good steady square on shot, as my hand drifted about.

So, being the geek that I am, I decided to use an astrophotographic technique.

I set the microscope to take video frames, and then took a video of the coin while holding the microscope as steadily as I could. The video I got had some of the frames that were slightly fuzzy (when I was too close or too far from the coin), some frames were in focus, and some of the frames were in focus on half of the coin and out of focus for the other half.

I gave the video to an app on my computer called PIPP. This sorted through the frames and assessed each one for quality, throwing out the worst 80 per cent. It saved the rest as another video.

Then I took this second video and opened it in a second piece of software called RegiStax. This looked over one of the frames for edges and other features it could easily identify, and then went through all the other frames for these same features. Once it had all the frames lined up nicely, it did some fancy mathematics to generate a single, sharp image. Finally, RegiStax has a sharpening tool, which I used as well.

Here's the image.

After having done all that, a mate told me about focus stacking software, which does a similar job. I'll have to look at that now!