1. To show how I set up to shoot the head of a disk drive (at viewtopic.php?f=27&t=46576)
2. To show how I shot the setup, using a small achromat to add close focus to the selfie camera of a cell phone.
First, here's the disk head:
Then, here are a couple of shots showing the setup.
The severed end of the disk arm is Bondic'd to a piece of 14-gauge copper wire, painted black and held in a spring clip that is magnetically mounted on the positioning stack.
Here's the view from underneath, looking up at a 50X objective.
I have no idea what all is being reflected in the front of that objective. It looks a little like me plus somebody else, but that's can't be right because the objective is looking down and I'm all alone, standing above the rig, holding the cell phone and looking down to see what the phone is seeing, looking up. (A masterpiece of clarity, that sentence.)
Finally, here's how that previous image was shot, by Blu-Tack'ing a small achromat in front of the selfie camera of my cell phone.
The achromat is about 40 mm focal length. Its job is to allow focusing on the disk head while still getting a nice wide-angle view. The exact specifications are a mystery. The lens came unlabeled in an experimenter's box of mixed lenses, some decades ago.
Yeah, it's a bit crude, but it worked OK and it let me see what I was getting while I held the camera under the apparatus looking up.
--Rik
