I've been doing lots of shooting with vintage adapted lenses lately. I was lucky enough to acquire a set of 5 lenses on a craig's list deal with a couple early 80's Minolta bodies and a bunch of accessories like a power winder, Kiron 2x TC, and some flashes, from a serious photographer who kept everything in like-new condition. Total: $99.
Here are images from the five lenses:
Manatees and marine biologist at Howard Park in Tarpon Springs with a Kiron 28mm f2, noticeable CA but it was correctable in darktable which sharpened the edges a lot

Canon M6ii, Kiron 28mm f2 in Minolta SR mount, Fotasy SR to EOS-M adapter, f8, 1/250s, ISO 100, processed in Canon DPP 4, CA corrected in darktable
Minolta MD Rokkor-X 50mm f1.7, a very sharp lens

Canon M6ii, Minolta MD Rokkor-X 50mm f1.7, Fotasy SR to EOS-M adapter, f8, 1/500s, ISO 100
A different Minolta MD 50mm f1.7 (no 'Rokkor' labeling) - also sharp but not quite as sharp as the Rokkor-X

Canon M6ii, Minolta MD (not labeled Rokkor) 50mm f1.7, Fotasy SR to EOS-M adapter, f8, 1/400s, ISO 400
An oddball in the set: Asahi SMC Takumar 50mm f2 in M42 mount - apparently the one with the radioactive rear lens element coating - surprisingly sharp and vibrant

Canon M6ii, Asahi SMC Takumar 50mm f2 in M42 mount, free-lensed on Fotasy Minolta SR to EOS-M adapter (it fit nicely with little play), f5.6, 1/60s< ISO 400
A large and heavy Vivitar 75-205 MC f3.8 apparently made by Kiron, optics are perfect but the aperture blades are covered in oil - had to take the lens apart and jerry-rig the auto-stop-down lever to become a 'manual' aperture 'mover'. Lens very sharp and contrasty by f8

Canon M6ii, Vivitar (Kiron-made) 75-205mm f3.8 MC, Fotasy Minolta SR to EOS-M adapter, 200mm, f8, 1/1000s, ISO 1600

Canon M6ii, Vivitar (Kiron-made) 75-205mm f3.8 MC, Fotasy Minolta SR to EOS-M adapter, 200mm, f8, 1/1600s, ISO 1600
And finally, I shot the Moon through my Meade ETX-90 telescope last night, and stacked 9 images with Registax software to get a sharper, less noisy image

Canon M6ii, Meade ETX-90 telescope (f13), Meade prime focus adapter, Canon EF T-ring, Canon EF - EOS M adapter, 9 exposures of 1/15 s, ISO 100 stacked using Registax and post-processed in darktable