I bought a nice condition (actually almost perfect, from eBay) M42 mount Helios 44-2 58mm F2 lens with an EF adapter to use on my EOS R6 (with firmware 1.3.1). The lens arrived today and I've been experimenting with it most of the morning. It definitely gives the nice 'painterly' look to the background that I was looking for when shooting wide open, and I do like the colour rendition. However, I haven't got my head around setting up the manual focus assist features on the R6, and what is and is not possible.
With the M42-EF adapter that came with the lens (no electronics), plus an EF-RF adapter, the camera needs the 'Release shutter w/o lens' setting in the (Orange) Camera 4 menu set to 'En