Steinheil Unofocal

[Roger Hesketh]

Their was a lens on Ebay the other day amongst a bunch of other lenses a Steinheil Doppelanastigmat Unofocal. I was not familiar with the lens so I looked it up in the 1920's Steinheil catalogue on the Cameraeccentric website.

http://www.cameraeccentric.com/html/info/steinheil_3.html

It would appear that the lens is a dialyte design similar to a Cooke Aviar an anastigmat but convertible the front or back components are achromatic yielding approximately twice the focal length of the complete lens. The catalogue suggests that the single components be used for soft focus portraiture at wide stops but that at small stops converted it makes a good group or landscape lens.

I made a too cheeky very low bid on that group of lenses and missed out but was sufficiently intrigued by the possibilities of this lens to find myself pressing the buy it now button on a 9x12 German folder which sported a similar lens later on that evening. Item number 160939141206.

Obviously I do not have the camera to hand yet. I would be interested to hear of the experiences of others with this or similar lenses used converted this way. I suppose it is too much to hope that it perform in a similar way to a Verito.
Thanks in advance.

Roger

[goamules]

I had one that was about 270mm, it's been sold. It acted like similar Tessar anastigmats; sharp and F4.5 speed. I didn't notice any softness.

[Steven Tribe]

In the rather "minor interesting" department, this lens is quite common in the UK as Beck had a client relationship with Steinheil at this time.
It was called the Beck unofocal and is identical to the German product unofokal.

[Roger Hesketh]

Thanks Steven I knew about the Beck connection. I get the impression, though I have no evidence to back up that impression, that the connection was similar to the connection Ross had with Goerz. In other words looser than the connection between Ross and Zeiss.

Garret the lens is a Dialyte with 4 uncemented glasses rather than a Tessar. If Sevo who posted on another Unofocal titled thread on here is to be believed if used as a complete lens it performs if anything slightly better than a Tessar of corresponding focal length and aperture. That is good news in itself but the Steinheil catalogue specifically refers to use of the lens converted were the use of the front or rear components results results in a doubling of the focal length.

85654

As you can see the catalogue states that used singly the components are Achromats rather than Anastigmats and that they are soft focus when used with large stops but sharpen up upon stopping down. I was wondering if anyone had experience of using them converted that they would be prepared to share.

Presumably used converted they must be quite strongly soft focus as and correct me if I am wrong please a 135mm f5.4 lens converted would become a 270mm f10 ish. If it is soft focus with such a relatively small maximum aperture it must be very soft . A Verito of corresponding length is beginning to sharpen up when stopped down that far.

[domaz]

The VM seems to rate these lenses very highly: "They should be brilliant and contrasty and
give even illumination and have especially good colour correction. In fact, until recently, one example, a
f4.5/150mm No 298,65x in a Compur was in regular professional use.".

I own one in 16.5cm and find it quite nice to use.

[Roger Hesketh]

Thanks Domaz. Yes I think it could be a find. Have you tried to use it converted?

[domaz]

Thanks Domaz. Yes I think it could be a find. Have you tried to use it converted?

The thought actually never occured to me. I will try it next time I get a chance though..