Gundlach Radar 12” anastigmat, a soft focus portrait lens?

[Whir-Click]

Everything I know about Velostigmat designs, specifications, and production dates is captured here: https://alphaxbetax.com/wollensak-le...er-compendium/

The above posts are spot on: Velostigmat was a trade name (like Radar, Ektar, etc.) and not a specific design. The Series II (Tessar design) was the only Velostigmat to offer a “diffusing device” which varied the spacing between the front elements to achieve a soft focus effect. As Mark Sawyer and others have beautifully illustrated in a separate thread, the Series II soft focus effect really shines with the limiting screw removed and the diffusing device cranked out by several full turns.

Wollensak discontinued the diffusing device around 1938. I’ve often wondered why the Series II didn’t run afoul of the Tessar patent and whether the diffusing device made a difference. That, or Wollensak’s exceptionally close relationship with the Bausch family and the Lomb family.

To the main topic, I have never seen the Radar Anastigmat F:4.5 touted as a soft focus lens in Gundlach trade literature, nor any indication that the lens element spacing was variable by design.

[diversey]

I have an Ilex Paragon Series A 12 inch lens with SF variable adjustment, 0-5 (the limiting screw was removed). This lens is similar to above-mentioned Wollensak Velostigmat II 12 inch SF lens. What is the best way to compare my Radar to my Paragon, and determine if my Radar lens has been modified for soft focusing or not. I’d like to solve this mystery. Thanks!

[Whir-Click]

Is there anything you can turn on your Radar that changes the distance of the front crown element relative to the front flint element? If not, if you remove the front crown, do you see a shim or spacer placed in the front mount that modifies the original placement of the front crown? Those would be my yardsticks for whether it is has been modified for soft focus.

[BrianShaw]

Perhaps shoot a couple of sheets of film… identical exposure and compare?

[Mark Sawyer]

Here's the thread on the Series II Velostigmat:

https://www.largeformatphotography.i...nfo-and-Images

As the Radar is a Tessar derivative, moving the single front element forward should increase spherical aberration, just like it does in the Velostigmat Series II and other Tessars. To my knowledge, the Velostigmat Series II and the Ilex Paragon Anastigmat f/4.5 series A were the only two Tessars to offer a factory-made method to alter the front spacing and induce soft focus. If you're looking for one, be sure to look for the engraved number 1-5 on the barrel, as it was an option and was not included of many lenses.

[diversey]

My Radar lens does not have a front turning thing, like variable adjustment. The front ring/crown is so tight that I couldn’t loosen and removed it. It would be nice to see if there is a shim or spacer inside.

Is there anything you can turn on your Radar that changes the distance of the front crown element relative to the front flint element? If not, if you remove the front crown, do you see a shim or spacer placed in the front mount that modifies the original placement of the front crown? Those would be my yardsticks for whether it is has been modified for soft focus.

[diversey]

Yes, plan to do so, but there are still many variables.

Perhaps shoot a couple of sheets of film… identical exposure and compare?

[diversey]

It makes sense that Radar lens owners put a spacer/shim between the front elements, and make a Radar lens as a soft focus lens.

Here's the thread on the Series II Velostigmat:

https://www.largeformatphotography.i...nfo-and-Images

As the Radar is a Tessar derivative, moving the single front element forward should increase spherical aberration, just like it does in the Velostigmat Series II and other Tessars. To my knowledge, the Velostigmat Series II and the Ilex Paragon Anastigmat f/4.5 series A were the only two Tessars to offer a factory-made method to alter the front spacing and induce soft focus. If you're looking for one, be sure to look for the engraved number 1-5 on the barrel, as it was an option and was not included of many lenses.