Richard J Kinch wrote:
Christopher Tidy writes:


I also need some lens-removing tools. Not sure what they're called.


You must mean spanners. Edmund Optics, Thorlabs for some pricey ones.
Ebay for a budget type.

What's the official name for these spanners?

Often the rings are hardly tight, and can be turned out with the tip of
a tiny screwdriver on one side, or the filed-down tips of needlenose pliers
on both sides. Give it a try.

I'm reluctant to try it. I don't want to cause any damage.

Many thanks,

Chris