View Full Version : Carl Meyer 305mm F4.5 image circle?

26-Dec-2014, 12:23
Just got handed a massive Carl Meyer Anastrigmat 305mm F4.5 lens (in a cool but huge Alphax shutter).

Can someone shed any light on this? I am assuming this is a classic tessar design, which covers 8X10 and not much more?

Dan Fromm
26-Dec-2014, 13:06
Count reflections and then you'll know whether it is a tessar type.

26-Dec-2014, 13:09
Any word on the image circle?

Dan Fromm
26-Dec-2014, 14:18
The lens could be nearly anything. Carl Meyer was a B & J house brand, they re-engraved, sometimes remounted and engraved, a wide variety of lenses as Carl Meyer. Now go count reflections.

26-Dec-2014, 15:04
4 in front group 2 in rear.... i am not sure i am counting them correctly....

26-Dec-2014, 15:11
Here you can see the 4 in the front, but not sure about the rear.

Dan Fromm
26-Dec-2014, 15:14
Thanks. I think you're using one light source, which is the best way. If the lens is a tessar type, you should see four strong and no weak reflections from the front cell, two strong and one weak from the rear cell. The weak reflection from from the rear cell may be quite hard to see. Also, there are times when the strong reflection from the front (or rear) surface can, believe it or not, be hard to see.

26-Dec-2014, 15:22
Dan - this is according to your above post a tessar lens, which what i suspected. Now - i tried checking various tessar of equal focal length and aperture of various makes, but could not yet find any kind of idea about the image circle. Do tessars have a specific angle of coverage?

Dan Fromm
26-Dec-2014, 16:27
f/4.5ers typically cover 110 - 115% of their focal length, stopped well down, whatever that means. My little 101/4.5 Ektar gives slightly soft corners on 2.25" x 3.25" at f/16.