Canon Backfocus on CCD Camera

[Bfialkov]

Hi

Based on the Interweb, the specified backfocus on the EF lenses are 44mm

Is it at all possible to use a CCD imaging train combo that will exceed this recommendation or will it just mean my Infinity marks on my lens are not really infinity?


I'd like to at least reuse one of my Canon lenses with a CCD combo before buying another longer focal length lens.


TIA


Barry

[Merlin66]

Barry,
The 44mm is correct.
To use and focus a Canon lens on a CCD/ CMOS camera you need to achieve this spacing. Any spacers, filter wheels etc, must therefore fit within this space.

[jahnpahwa]

If your CCD is a zwo, you can get an EOS adapter for direct to ASI camera, and anotehr one for EFW filter wheel, both (as I read) designed to bring EOS DSLRs with mirrors to the correct backfocus.

I plan on using these. If the above is incorrect, please do point it out!

https://astronomy-imaging-camera.com/product/new-eos-t2-adapter
https://astronomy-imaging-camera.com/product/eos-lens-adapter-efw-asi1600