I know there are also FD-to-EOS adapters, but they include an additional lens , and nested adapters are bad for stability....
https://www.teleskop-express.de/shop/pr ... ktive.html
but a bit improved
that Geoptik thing is great, but still has few issues (from my point of view of an experienced imager).
- It has a small locking nut - my friends solution - see here http://teholagr.blogspot.com/2011/11/ud ... apter.html
is much much more rigid and robust (original idea came from the Geoptik adapter)
- It has big 19mm thickness so it eats 19mm from the BFD that is 44mm for Canon lenses
since for ZWO cameras having typical back focal distance of 26.5mm the 19mm geoptik adapter is unusable.
Hence, if ZWO offers just the front part - EOS lens with contra-locking-nut (making zero tilt of the lens attachment) - and with shorter back focal distance, say no longer than 17mm (ideally 15-16mm because a spacer/washer can always be added to make it longer) then it would be GREAT!
it may need only M54 or M42 classic T-threads on the back side and possibly accommodate 2" internal filter (exactly as geoptik thing does).
easy... such an adapter doesn't exist on the market, AFAIK (the Geoptik is good, but not that perfect as I'd like it to be - shorter without obstructing "leg" that prevents attachment of larger square body cameras)...
just my $0.02
(ZWO already has an EOS adapter, and I specially want one for FD lenses, not EOS (FD has 42mm BFD). Another EOS adapter doesn't help me anything)
In our photo community (normal, not astro) there's quite some people using old FD lenses with adapters. I thought as it is a quite simple thing (just T2-ring with a bajonett) it might be easy to set up/build and therefore suggested it.
But I do understand it's likely not high on the priority list