how optical filters are made

[AgX]

Shown at the german manufacturer Heliopan.

Most probably nothing that surprises you, but maybe nice to see:

http://vimeo.com/67566198

advance to 11:20 to start video

 

[Ricardo Miranda]

Thanks!

 

[AgX]

I admit I was surprised to learn that each filter is polished seperately. I expected them to be cut from a polished plate. Though, that would necessitate quite some effort to keep the main surfaces unharmed during breaking and edge grinding.

 

[E. von Hoegh]

I admit I was surprised to learn that each filter is polished seperately. I expected them to be cut from a polished plate. Though, that would necessitate quite some effort to keep the main surfaces unharmed during breaking and edge grinding.

The thickness is critical, it's what determines the density of the finished filter. Also, it's probably more ecomonical to maintain plane/parallel surfaces when polishing individual filters on a block.