Heliar front "sub-cell" - softness adjustment?

[renes]

I came across an information that the rear element (sub-cell) of the front Heliar cell can be unscrewed till 1.5mm and this can be used for adjustment of softness effect...

I coud not confirm this "revelation", and never heard about it. Did you, or someone tried it? I checked all my Heliars 105/120/135/150/165mm and last three have it.

Here's a picture made by Uusilehto which shows it:

http://img97.imageshack.us/img97/2066/heliar.jpg

[BarryS]

This is similar to the adjustment built in to the Universal Heliar to achieve soft focus effects. The middle element can be shifted to induce spherical aberrations. I don't know if the Universal Heliar adjustment moves the middle element forward or backward. Obviously, in hacking the normal Heliar, the middle element can only be moved back from the optimal position. I'd like to try it on my 360mm Heliar once I get it mounted to my studio camera.

[Jim Galli]

One of the old catalogs seems to indicate the small amount of movement available with a couple of threads may not do much compared to the travel that the mechanical Universal had.


http://tonopahpictures.0catch.com/Univ-Heliar.jpg

Also the universal Heliar was the earlier design with the concave glass outbound where your later Heliar is convex glass outbound. Just not sure it will do anything noticeable near what the Universal would.

[Arne Croell]

This is similar to the adjustment built in to the Universal Heliar to achieve soft focus effects. The middle element can be shifted to induce spherical aberrations. I don't know if the Universal Heliar adjustment moves the middle element forward or backward. Obviously, in hacking the normal Heliar, the middle element can only be moved back from the optimal position. I'd like to try it on my 360mm Heliar once I get it mounted to my studio camera.
In the Universal Heliar, the center element moves forward when increasing the "softness", by quite a distance (about 26-27mm for the 420mm Universal Heliar, going from "0" to "5"). Another difference is that the Universal Heliar outer groups are slightly different from the regular Heliar: The Universal Heliar is a "true" Heliar with the outermost lenses being a negative meniscus as shown in Jims picture, whereas most of the regular later Heliars are "Dynars" with the outer lenses being biconvex and cemented to a biconcave one.
However, experimenting is fun!

[renes]

I won't believe that no Heliar users did not check it yet !?

[Steven Tribe]

The Universal Heliar was just 12% more expensive than the F4.5 Heliar in 1934/1935.
The F3.5 Heliar was 11% more expensive than the Universal Heliar at the same time. Times change!