New specimen holder

Rylee Isitt · Post by **Rylee Isitt** » Fri May 18, 2012 8:31 pm

I recently modified my lego copy stand so that it can also do horizontal work. With this kind of work, I wanted a more flexible specimen holder.

While I am working on a more fancy specimen holder using Newport stages and rails, this is my current setup:

The Lego bit is just a vertical stage and also allows the specimen to be rotated in one axis. It's zip-tied to a 5lb weight with rubber feet attached on the bottom.

The rest of the movements are done with the ball. This is a hollow, plastic practice golf ball filled with plaster of paris with a "fun tack" (it's like sticky tack/blue tack except white) center. The specimen on a pin can be pushed into this.

It's based on a design mentioned by my entomology prof, and I found further details here on how to make them: http://tech.groups.yahoo.com/group/beem ... ssage/1785

Vibration does occur, but diminished quickly. So far I shoot with flash so vibrations do not affect image quality.

Here's a test shot with a bad lens, but I was more interested in registration problems due to vibration from one shot to the next. There were a few, requiring me to crop edges slightly. This is a stack of 70 frames, pushing my stepper to the limit as each frame was only a single half-step advanced.

abpho · Post by **abpho** » Fri May 18, 2012 8:41 pm

Very smart. I'd love to see a three axis model.

I bet the kids got upset when you started raiding their lego set.

Rylee Isitt · Post by **Rylee Isitt** » Fri May 18, 2012 8:44 pm

Ha, nope, I'm a solitary student. These LEGOs belong to me. If I had kids, they have to get their own!

I didn't think a 3 axis approach would be necessary until I started using it. I thought I could just pick it up and move it around. But yup, 3 axis control would make things easier for sure.

abpho · Post by **abpho** » Fri May 18, 2012 8:54 pm

Cool. I just use a third arm parts holder. It can be a little finicky sometimes. But once it is set it is solid.

Rylee Isitt · Post by **Rylee Isitt** » Sat May 19, 2012 4:51 pm

A third arm is a great idea, and I happen to have one laying around. That could be a less fiddly approach for some specimens.

Thanks for pointing this out!

Craig Gerard · Post by **Craig Gerard** » Sat May 19, 2012 6:16 pm

Rylee,

Watching with interest

Regarding the 'fun tack'; some time ago, another member, involved with the watchmaking profession, sent me a packet of putty called 'Bergeon Rodico'. Surprisingly it is designated for use as a cleaning product but also serves the purpose of holding entomological pins for subject placement during photography. I've also found a small amount is very useful for holding mineral samples to stage plates when photographing.

Craig