The adapters allows you to use vintage lenses such as 'Chinon' and 'Ensinor' lenses on your Canon DSLR. The adapter simply turns the vintage mount, for example M42 or T-Mount, into the mount needed to attach to your camera.
One of the vintage lenses that I am using is the Chinon 200mm f/3.5. The videos below shows some shots that I captured using this lens, along with the M42 to EOS adapter on my Canon EOS 600D DSLR.
Another test is using the Ensinor 500mm f/8 Multi Coated mirror lens with my Canon 600D. The colours came out very flat, but with basic colour correction I managed to bring the colours back out.
The M42 to EOS adapters can be found on eBay from £1.85.