I guess I must be over thinking it, but I cant figure out how this thing works. I get that I can move the inner male thread out and then lock it inplace, but all this is doing is exposing more of the thread, not making the adapter wider?
The issue is that if its just exposing more thread, then it wont change the spacing because the thread will just get swallowed up by whatever it gets screwed into.
I agree the Baader 12-16 mm variable adapter is tricky to work out at first and even with experience, it is possible to over screw and everything suddenly falls apart. I found the one linked below a much better design (albeit twice the price!) and the 15-18 mm spacing covers a similar range https://www.testar.com.au/products/m...MaAtHoEALw_wcB
FWIW, I’ve been trying out the Baader M68 15-18 variable extension. Whilst the concept is good I find that unlocking the “locking” ring results in the whole unit unscrewing from what ever it is screwed into, particularly once it has been secured in the image train. I was hoping that it would allow me to make small adjustments to the back spacing without having to disassemble the image train but it doesn’t appear that this will be practical. For now I have gone back to a combination of extension tubes and thin spacers.
Last edited by Ryderscope; 27-02-2024 at 10:04 AM.
Im making a variable extension adapter with built in tilt adjustments, at the moment for someone. It has +/- 2mm of variable spacing and this version only consumes 22mm of backfocus (including tilt adjustment). One of the good things about it is there is no unlocking of threads to adjust the backfocus. I will post details of it when its finished.