Another 35mm adapter question (sorry)
 

Hey guys, first post here. Sorry for asking a question right away.

I'm building my own 35mm adapter and was trying to come up with a way to make sure the grounding glass is level. I was thinking of using a polarizing filter to make this work. My question is, will this work the way I hope it will, where one of the sides of the PL filter will spin, and thus anything screwed onto the end of it will also spin? Obviously I would remove the actals PL filter and just use the spining ring.

What do you guys do to make sure the GG is properly oriented?

Thanks!

You need three axis adjustment for your groundglass relative to the optical centre axis or relative to the face of the SLR lens mount.

You also need to build in a three axis adjustment for attachment of the camera/close-up lens to the adaptor.

http://www.youtube.com/watch?v=CnweOEEqlRY

Shows in part, how I did it. Three axis for the GG is adjusted by the motor mounts. Three axis for the camera is adjusted by skewing the rear cap until accurate then drilling the screw holes.

To set it all up I used a Lemac Chart, positioned accurately on the optical centre axis and centred. It is a sort of a text pattern with a Siemens star in each corner.