Trouble mounting a Schneider 150mm convertable. Help!

[riooso]

I am new at this and have a question. I searched for my problem but it is hard to describe.
I am so close to getting started this is killing me!

Schneider Symmar 1:5.6/150 mm convertable.
Copal No1 shutter.

I finally got the correct Toyo lensboard (110mm x 110mm). When I take the ring off the back of the lens to mount the lens there is a screw that sticks out above the back of the lens about 3/32 of an inch and will not allow the lens to lay flat. What is it? I did not try to tighten it for fear it is a calibration screw for the shutter.

1.Does one drill a small hole so that the lens lays flat?
2.It seems to me that the apature ring will rub the lensboard but hopefully the collar behind the lens is out a couple of thousands.
3. This is really getting greedy but how do you "convert" the lens?

Thanks,
Riooso

[Sheldon N]

It sounds like a mounting pin. You can either drill a small hole to accept the screw, and then the lens wont twist in the lensboard mount. Or, you can unscrew the pin entirely and just mount the lens with retaining ring tight enough so that it doesn't spin.

I just removed the pins from my Fuji lenses, and they still mount fine.

[riooso]

Thank you so much.

RioOso

[bauschj]

River Bear,

The conversion is usually done by unscrewing the front element. That way you can get close to double the focal length. But don't count on too much image quality off axis. The best way to control lateral chromatic aberration is with a lens that is symettric about the aperture. (Hence the name Symmar) but when the front element is removed, all bets are of. I think this is the reason that Schneider discontinued their convertibles in the early seventies.

Jim

[Brian Ellis]

Remove the screw, you won't need it as long as you tighten the retaining ring properly and keep it tightened. I carry a small spanner wrench around with me in case the lens comes loose in the field.

As Jim said, you can't count on excellent technical quality from negatives made while in the "converted" mode. However, you can improve the quality somewhat by holding a yellow or orange filter in front (assuming you've removed the front section of the lens to convert it) of the shutter when making the exposure. Just make sure your fingers don't get in the picture.