Eos adapter question

[Gingerbones]

Hi
Trying to find an adapter for some of my old equipment but struggling to find what i need.
I can get hold of a m42 - eos adapter easily enough but i would like to try getting an adapter that will go the other way.
The reason for this is that I have an old m42 2x converter that i would like to use in conjunction with my eos lens.
So i need to find an adapter that will have the eos fitting to an m42 thread on one side of my 2x converter then a convetional m42 - eos adapter on the other side of the converter that can then attatch to the camera body
Can anyone point me to a site that i might be able to do this
Thanks

 

[Alastair]

To be honest, I wouldn't bother.

You're very unlikely to find the adaptor you're looking for on-the-shelf - the reason that an m42-EOS adaptor works is that the EOS register distance (gap between the lens mount and the sensor/film) is shorter than the m42 register distance. Which is the reason why an EOS-m42 adaptor would have very limited usefulness (it would be too long and an instant macro tube with loss of infinity focusing). Extremely limited usefulness if your EOS lens has no aperture ring (do any EOS lenses these days?).