Bizarre Lens Defect

[Nodda Duma]

I'm aware of that; I chose the V-blocks because the diameters are identical within my ability to measure, it was that or nothing.

Yep, figured you knew what you were doing. I added the caveat for the benefit of future info searchers.

 

[E. von Hoegh]

Yep, figured you knew what you were doing. I added the caveat for the benefit of future info searchers.

Good idea. I didn't have the internet in the 1980s, I actually had to read books & stuff and (gasp!) think about it for a bit! I read one internet suggestion to use a piece of paper rolled into a tube... makes me sad to think of all the nice stuff, things which never will be made again, being ruined by bad ideas off the web.