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

[diversey]

I also got a Gundlach Radar 12” anastigmat lens when I bought the Century Master Studio Camera. When I cleaned and inspected the lens, I saw the front ring that keeps front lens elements in position in the front cell was not completely screwed in, two or three thread turns left behind, see the picture below. I was wondering if the former owner did it intentionally. From literature, the radar lens has 5 elements, 2 separated elements in the front cell and 3 cemented elements in the rear cell, see a picture below. I just felt a little odd about this lens.

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[BrianShaw]

I use a 5x7 Radar lens. Definitely not intended to be soft focus. It is a variant of the Tessar design.

[BrianShaw]

The front cell retaining ring on mine stands a bit proud also. Now quite as much as yours, though.

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[Tin Can]

Intentional aka uncorked

Somebody here was an expert on it

Jim Galli

I have factory Radar SF and the normal like yours

I only have one flange and they differ

[Louis Pacilla]

I have never seen factory Radar SF versions Randy can you post a photo of the lens just out of curiosity with maybe a side view that show the markings for soft focus separating the front group?

Thanks Randy in advance.

[BrianShaw]

I’ve never even heard of a “Radar SF version” lens. Gundlach made several SF lenses but none, to the best of my knowledge, was called Radar or used the Radar lens design. I’m interested in what Randy has too!

[Tin Can]

https://picclick.com/Gundlach-8x10-12in-f45-Radar-Anast-Betax-5-374323477902.html?refresh=1


I will dig mine out tomorrow IF I remember

There was a big discussion here about unscrewing the rear as far as possible

One of mine is...

[Tracy Storer]

Same. The front ring on mine protrudes about 1mm (0.042")


The front cell retaining ring on mine (12" focus) stands a bit proud also. Now quite as much as yours, though.

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[Vaidotas]

I also got a Gundlach Radar 12” anastigmat lens when I bought the Century Master Studio Camera. When I cleaned and inspected the lens, I saw the front ring that keeps front lens elements in position in the front cell was not completely screwed in, two or three thread turns left behind, see the picture below. I was wondering if the former owner did it intentionally. From literature, the radar lens has 5 elements, 2 separated elements in the front cell and 3 cemented elements in the rear cell, see a picture below. I just felt a little odd about this lens.

233380233381

Jim Gali once wrote about pimping tessar in to softness realm by putting a spacer between first and second lens elements. He used molding wire as a spacer.
Ross Xpress (rarely seen in longer FL), Berthiot Olor has the same layout as Gundlach Radar if anyone looking for an alternative.
You can use rear cell only with almost the same FL as soft lens.

[diversey]

The protrusion of my lens is so significant 2-3mm at least. The front ring threads should not be shown. I was wondering either the front cell was modified or not put back correctly after cleaning.

Are there any photo examples available taken by modified Radar lens?

[Tin Can]

I think it was common

and now I do recall front markings for rotating out for soft

Jim Galli was/is an influential SF guy

I need to dive into my lens bank today

I most likely will be back with pics

[Tin Can]

Pics not necessary

Perhaps we should ask the Wollensak expert

I have 2 iterations of a similar lens, Gundlach 300mm 4.5 Radar is heavier

The second is in better condition, Velostigmat Series 2 300mm 4.5 and much lighter

Some members told us to unscrew front or back to make it slightly SF

[BrianShaw]

@diverisity... So what do the images through the lens look like, either on GG or negs? Are they in focus; are they soft; are they sharp, as Gundlach intended?

[Tin Can]

Both are more sharp if stopped way down

as usual

I need to mount one on a 8X10 Home Portrait lensboard

[BrianShaw]

Both are more sharp if stopped way down

as usual

I need to mount one on a 8X10 Home Portrait lensboard

Thanks, Randy. As one would expect from a Tessar design lens, which both RAdar and Velostigmat (probably) is. The Velostigmat name was used over such a large period of time I'm just not too sure about them.

I was really asking @diversey about his lens. Something looks potentially modified or improperly assembled about it.

BUT... look at this one... it appears very much like yours, @diversity... most don't seem to have as much thread showing as yours and this one... Could this be "normal" manufacturing/assembly variation?

https://www.ebay.com/itm/374323477902?hash=item57276afd8e:g:xRoAAOSw7vNjWe6B&amdata=enc%3AAQAHAAAAoLgsVKOufhDBjlCNr%2BJlKolz9AiO7dpiIaCpt%2BrnWnPM1l918bKivYxI%2BMHeXtg0NPWPWQFS3Ws%2B7pgOxfkcYGlhZB%2BrLcPokYho0S%2Bdq%2BX2eeqGxCZXQ8rEC668bePTdlev7Tf8WaNhw3sWz%2FNJkTaBIclQG02D0OMGwxj6uTJK%2BqtGOBde6cZjy8poAscAKMy7K50h2HjUwlirniGpjWc%3D%7Ctkp%3ABk9SR_zvoc-dYQ

[diversey]

Brian: I did see a soft image on GG at F4.5, wide open. It was hard to tell this soft image was due to “soft focus. David


@diverisity... So what do the images through the lens look like, either on GG or negs? Are they in focus; are they soft; are they sharp, as Gundlach intended?

[diversey]

It is hard to believe that the front ring from this high grade lens could not be completely screwed in, even after disassembling and cleaning.



Thanks, Randy. As one would expect from a Tessar design lens, which both RAdar and Velostigmat (probably) is. The Velostigmat name was used over such a large period of time I'm just not too sure about them.

I was really asking @diversey about his lens. Something looks potentially modified or improperly assembled about it.

BUT... look at this one... it appears very much like yours, @diversity... most don't seem to have as much thread showing as yours and this one... Could this be "normal" manufacturing/assembly variation?

https://www.ebay.com/itm/374323477902?hash=item57276afd8e:g:xRoAAOSw7vNjWe6B&amdata=enc%3AAQAHAAAAoLgsVKOufhDBjlCNr%2BJlKolz9AiO7dpiIaCpt%2BrnWnPM1l918bKivYxI%2BMHeXtg0NPWPWQFS3Ws%2B7pgOxfkcYGlhZB%2BrLcPokYho0S%2Bdq%2BX2eeqGxCZXQ8rEC668bePTdlev7Tf8WaNhw3sWz%2FNJkTaBIclQG02D0OMGwxj6uTJK%2BqtGOBde6cZjy8poAscAKMy7K50h2HjUwlirniGpjWc%3D%7Ctkp%3ABk9SR_zvoc-dYQ

[Mark Sampson]

The Wollensak Velostigmat is a Tessar design. Some versions allow you to move the front element outward to achieve soft focus (I had a 12" and never tried it). Some people here (Mark Sawyer?) did not think it went far enough, and found even softer focus by modifying the lens barrel to allow more un-threading of the front element. There's a thread here somewhere that explains it.
The Gundlach Radar is a different design with more lens elements, not a Tessar AFAIK. Gundlach and Wollensak were cross-town competitors back in the day. I have not used a Radar lens (a pre-WWII name btw, not connected with today's radar technology), but can't imagine why the front element protrudes, as here. A little testing might give the answer.

[Darren Kruger]

As one would expect from a Tessar design lens, which both RAdar and Velostigmat (probably) is. The Velostigmat name was used over such a large period of time I'm just not too sure about them.


The Velostigmat name was used on a variety of lenses of different types. They were differentiated by the Series label.

Velostigmat Series 1/1a -> Convertible lens closer to a Protar I think.
Velostigmat Series II -> based on the Tessar design.
Velostigmat Series III/IIIa -> Wide angle (not Tessar or Protar based)
Velostigmat Series IV -> lower cost and slower lens which I think is based on the Tessar design.

I hope Whir-Click chimes in as he would be more familiar with the details for each series.

-Darren

[BrianShaw]

The Gundlach Radar is a different design with more lens elements, not a Tessar AFAIK. Gundlach and Wollensak were cross-town competitors back in the day.

4.5 Radar is indeed the Gundlach equivalent of a Tessar design with the extra element to avoid patent infringement: 5 element 3 groups with 2 separated in front of the aperture and 3 cemented at the back.

http://www.eenportfolio.nl/Gundlach_jul1930.pdf

The Radar WA (wide angle) is a completely different lens design.

[Whir-Click]

Everything I know about Velostigmat designs, specifications, and production dates is captured here: https://alphaxbetax.com/wollensak-lens-and-shutter-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.info/forum/showthread.php?57385-Velostigmat-Series-II-Info-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.info/forum/showthread.php?57385-Velostigmat-Series-II-Info-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.