A Mighty Pen

Fountain pen tip magnified 12x

I built a video-based microscope for work yesterday, and today I took that same hardware and converted it for use with my Sony camera. This is about 2.6mm of the tip of a vintage Pelikan fountain pen.

I love writing with fountain pens, and vintage models have a special place in my heart. They have a certain springiness to them, and are wonderful to write or draw with.

I don’t know the name of this particular model, but it was likely a business pen; the type of the nib is “ST” which was commonly used by stenographers. It was meant for fast writing, good ink delivery, and was reasonably stiff to allow for good control. Even after about 75 years, it delivers on all of those qualities.

The microscope objective is a 10x model; I got to 12x by putting it a bit further from the camera sensor that it is designed for (about 180mm instead of 160mm). It is a sharp objective, but only the central 50% or so looks right - outside of that zone, the image is blurred a bit. That is why I stretched to 12x; I used more of the sweet spot that way. The weak portions are at the edge of out of frame.

Technical info: a focus stack of 15 frames. The distance between frames was 5 microns, but that was really too large a step size for the magnification level. (The step size was larger than the critical focus zone; you can see the zones of imperfect focus if you know what to look for.) Next time, I would use 2.5µm or maybe 3µm with this setup. Exposure was 1/4sec. for each image.