Julius Laack & söhne Rathenow, Dialytar 6.8/155 mm

[Karlpeter]

Can anyone bring me some information about My Laack Dialytar doppel anastigmat 6.8/155 mm serial number 26054. How old? Image circle? Can't find anything on Internet about it. It's mounted in an IBSO shutter 1 s. to 1/100. The shutter was manufactured between 1908 and 1926 from what I have found.

Peter

[domaz]

Almost certain a dialyte design lens (just judging by the name). Probably has coverage of around 60-70 degrees. Bokeh on dialyte lens tends to be well regarded.

[Dan Fromm]

Almost certain a dialyte design lens (just judging by the name). Probably has coverage of around 60-70 degrees. Bokeh on dialyte lens tends to be well regarded.

That's what one would think. The VM reports on a 135/6.8 Dialytar, says it is a dialyte. But they also say that f/2.7, f/3.5, f/4.5 and f/6.3 Dialytars are tessar types. Except that some f/3.5ers are triplets. Others were 4/4 double Gauss. And, finally, some early Dialytars really were dialytes.

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