Are newer mirrorless crop sensors better than older full frame DSLR sensors?

[wojo58]

Hello, 

   I recently purchased a R7 recently with the RF100-400mm lens for wildlife photography, with birds being the main subject. To get better performance in low light conditions (like deeper woods or inside buildings) I was thinking of getting an older (used) full frame DSLR camera to augment my kit. Staying in the Canon camp, would it be a waste of money to get a used 6DMk2 , or should I just save up for better glass?. I don't want to spend a lot on  this camera as it would not be used nearly as much as the R7. Presently the only full frame DSLR lens I have is the Canon 24-105 STM (non-L). Thanks for your all's input!

[kvbarkley]

Have you seen an issue with the R7?

I would transition from the R7 to an R8 or R6 MkII.

[wojo58]

Thanks for your reply...

No issue.  Just a general question really.  I know sensors of comparable age/generation will have the full frame sensor gathering more light and *presumably* giving better signal to noise ratio compared to the crop sensor. The old cropped vs full frame debate. .  But what about a *newer* crop sensor vs an older full frame?  At what point would a newer technology crop sensor beat the old full frame one?  Hence my question about R7 (2022) vs 6Dmkii (2017).   Not sure as well if the mirrorless vs DSLR would influence the signal to noise ratio.  To put it short:  I would like to get a used (read cheaper) low light performer as a second camera.  Assuming used as well.  

[kvbarkley]

I asked if you had issues because the R7 - because of its small pixel size - is notorious for poor low light performance.

A good way to compare is to use Ken Rockwell's site. For many cameras he has the same image at a number of ISO's so that you can directly compare.

Here is the 6dMII

https://kenrockwell.com/canon/6d-mk-ii.htm

[p4pictures · Accepted solution]

If you want to get an inexpensive 2nd body that's full-frame then you should consider the EOS R6 (mk1) as it will still fit with your existing RF 100-400mm lens. It has some of the largest sized pixels of any recent full-frame camera.