Need help - Steinheil Orthostigmat convertible

**tangyimail** · 7-Mar-2014, 08:16

Dear all,

I have a Steinheil Orthostigmat that seems to be a convertible design. Front and back combined gives a focal length of 13.5 cm with max aperture of 6.7, front has a focal length go 26cm and back 22cm.

If I want to use just front or back element, what kind of aperture will I get? It is not indicated on the shutter as some of the old convertible lenses seem to have.

Thanks

TY

**Roger Hesketh** · 7-Mar-2014, 09:11

It is triple convertible f12.4 and f14.

**tangyimail** · 7-Mar-2014, 16:22

Originally Posted by Roger Hesketh

It is triple convertible f12.4 and f14.

Thanks Roger.

**Roger Hesketh** · 7-Mar-2014, 18:05

You're welcome. Just a thought. The maximum aperture of your lens is 1 & 13/16 of an inch (4.59cm) . You could use that figure to help you to calculate an aperture scale.