[Brightcolours]

If you are talking about that kind of results, well that's exactly what I got when using it on my 300D.

BTW not only the 58 but also the 300mm couldn't focus to infinity using the adapter, maybe it was a bad adapter ?

If you follow this thread with attention, you will see that Dave shot those images after he modified the lens on purpose (reversing the front element). That then may be a reason why you got such results, that a former owner somehow did the same?

 

About adapters... M42 adapters should be about 1.5 mm thick for EOS mount. If yours was significantly thicker, you had a very odd one. If not, the lenses should focus to infinity, or they were somehow broken.