Dedicated M42 adapters are available for the Canon EOS cameras, The Pentax *iST D and K series, Minolta MD and AF, Nikon, as well as for the Olympus and Panasonic 4/3rds system. On the Sigmas, a Pentax K to M42 adapter is used, which is a very close fit but not perfect. There is a Japanese CSM42 dedicated adapter available for the Sigmas, but quite expensive. But it is a perfect fit and it has a built-in flange to use M42 lenses with aperture pins.

 

Although not an issue on Canons, Minoltas, Olympus, Panasonic, Pentax's and Sigmas, M42 lenses would not focus to infinity on the Nikon cameras with the normal Nikon to M42 adapter. The Nikon's registration distance differs from the others, and the lenses do not go deep enough into the Nikon's body with the normal adapter to give infinity focus. Proper Nikon M42 adapters are available which include a correction lens to overcome this problem.

 

I personally prefer the Sigma CSM42 adapter on the Sigma cameras, because of it's built-in flange. Quite a number of M42 lenses have aperture pins sticking out at the bottom of the lens, and these pins must be depressed to make the apertures work. And the best way to do this, is to glue them with super glue, which is not the nicest thing to do to these beauties.

 

And I personally prefer the image quality the Sigmas generate with M42 lenses. Don't know if it is the Foveon sensor, but my Canons, Nikons and Pentax cameras just do not give me the same results.