Steinheil Orthostigmat 36 cm. f6,8

[qiutaolee]

How about is Steinheil Orthostigmat 36 cm. f6,8 on 8x20?Does it have some movement?Which one has much movement on 8x20 between Voigtlander Collinear serie III 36 cm. f7,7 and Steinheil Orthostigmat 36 cm. f6,8? thank you!

[Mike Gudzinowicz]

The Steinheil Orthostigmat 36 cm. f6,8 is a 6/2 convertible design which is
reported to cover an angle of 85 degrees. That should give an image circle
of approximately 660 mm, and on 8x20, one might expect movements of
2.6" to 4.6" depending upon orientation.

The Voigtlander Collinear 3 was manufactured with apertures of f6.8
and f7.7 with focal lengths ranging from 2-23". Like the Steinheil, it is a 6/2
convertible design, however, the coverage angle is listed as 66 degrees. The
minimum focal length just to cover 8x20 would be 421 mm or 16.6", so it
appears that a 36 cm lens won't cover the format.

Be advised that the "specs" on many old lenses aren't specifications, but
are speculations. A 355 mm f/7.7 Dagor is probably a better (safer) choice.