Connecting Canon EOS R cameras to T2 and M48 lenses and telescopes
Canon R mirrorless cameras use a different thread than that found in old Canon EOS DSLR. Existing adapters won't work, although there are Canon R to Canon ES adapters and you could try your from that.
Among new adapters, we have quite a few options, found on Aliexpress and in local photographic equipment shops.
Lens adapters like the T2 or EOS EF/EF-S aside from changing the thread also try to set the sensors in the correct back-focus distance from the lens. That's why this T2 adapter is so tall.
It can also be used in Astrophotography or when adapting smaller telescopes for standard photography, but depending on your scope choice you may be limited on back focus and then a low-profile version will be required.
I did a few test shots with Canon R50 and 200/800 Newtonian (f/4) and at such focal lengths, air turbulence starts to play a role (and wind shaking the tree). Newtonian at f/4 will require perfect collimation and a comma corrector (used in the shots below). The focus depth for daytime photographs will be very small.
This is a low-profile adapter I got cheap from Aliexpress. It's wider than T2 and has better compatibility with 2" accessories that often use M48 thread.
With a RedCat 51 refractor (f/4.9 51/250mm) I managed to get some shots from hand when chasing birds. This refractor does have a very limited backfocus and even with this adapter it is limited by it for short-range focus.
To use Canon R cameras with a manual lens you have to set it to manual mode (like the
M mode) and then enter the menu and allow shutter release without a lens (as the lens is completely manual with no electronics and the camera has no idea about it).