Jos. Schneider Kreuznach Doppel Anastigmat Isconar 135mm f/6.8 Lens

[Sanford]

Does anyone have any information on this lens? I have done a few searches, but I haven't found anything about this particular lens.

[Chauncey Walden]

Dan Fromm once posted info from the Vade Mecum that said "Isconar f6.8 This was a slower version of the above [f4.5] Frerk says both are Gauss type dialyts". In my experience they are good lenses.

[IanG]

I have one, a 165mm f4.5 which came with a half plate Gandolfi, unfortunately in poor condition, it might clean uo optically but there's no blades in the shutter.

As above it should be quite a good sharp dialyte, similar to my 135mm f4.5 Rodenstock Eurynar which is an excellent lens, but like all uncoated dialyte lenses will be quite low contrast. I tested a few lenses last February all in excellent optical condition and the dialyte had less contrast than a tessar ,a nd both were way behind a 1913 Dagor.

Ian

[Sanford]

Thank you for the replies! I shot a couple of sheets with the lens yesterday and I think Ian nailed it, it is nice and sharp, but very low in contrast. It will be fun to play with for a while

[IanG]

Thank you for the replies! I shot a couple of sheets with the lens yesterday and I think Ian nailed it, it is nice and sharp, but very low in contrast. It will be fun to play with for a while

What you need to remember is before WWII it was common to expose more and process for longer often in Pyro devs to produce negatives with much greater densities and contrast than we aim for today and the papers matched those negatives. This helped with lower contrast lenses and because the Pyro developers produced much heavier staining than PMK or Pyrocat HD etc highlights had less tendency to block up.

You can increase contrast in development to partly offset the lower contrast of the lens. I use a couple of coated dialyte lenses quite regularly , both 203mm f7.7 Ektars one US made in a Compur #1 the other British made in a Prontor SVS #0, and they are very sharp lenses and excellent from Infinity to 1:1. Coating makes a huge difference and the Ektar's have excellent contrast.

So try increasing development by say 20% when using the Isconar, it should help a bit.

Ian