The Canon EOS and Photography Forums

Thanks for the membership of forum. i am from Lahore Pakistan.  i searched the forum but not sure whether it is proper place to put question relating to eos 1n and M42 adapter. Using manual adapters OM/CY/Nikon/Pentax bayonet/screw on 300D/Rebel freely with different lenses. Similarly my film bodies Rebel/300 and 55E also accept all these adapters. But when i attach with eos1N bodies mirror stuck up and on next shutter push mirror is released. i have pentax bayonet mount AF adapter and branded screw mount fitted in it all picked from ebay. IMHO 1N mirror is long which grip the adapter. i read somewhere on net it can be shaved. I am non technical person any act can damage my gear. Seeking expert advice and if required shorten the mirror or any other adapter help me.

Usually there is no problem with M42 adapters and screw mount lenses, though a few lenses (such as The Pentax screw mount 50/1.4) may interfere with the mirror of full frame cameras when focused at infinity.

Most Pentax-K mount lenses will have problems with full frame cameras due to intereference between the mirror and the aperture coupling lever of the lens. Either the lens or the mirror needs to be modified. If you are non-technical, I'd leave the mirror alone since you could damage the camera. Modifying the lens is often easier (cut off the parts that the mirror hits), though that will mean it can't be used as designed with Pentax-K mount bodies.

Thanks Bob for the advice. Perhaps it is thickness of the adapter. i attach Pentax K to Eos AF adapter inserted pentax own screw mount adapter and on  attaching takmars or tomioka, Bonotar lenses EOS 1N is behaving  as per my earlier request. There are lot of screw mount adapters for eos film and digital on ebay but seeking ur advice on  adapter thickness/made so that may able to use my collected takmars/CZJ/Binotar on this film body.