Large Dallmeyer Lens

[e]

I own the same lens you have, a Dallmeyer 4b f3. Use it wide open, don't bother with f stops. It will astonish you! I have used this lens as a portrait lens on 12x20 but it is great on an 8x10 too, although straining my Deardorff's front end. This lens is best at portrait distances as it only covers 5x7 or such at infinity and will need to be stopped down. It really lights up the GG on 12x20 at F3 though. Emile/www.deleon-ulf.com.

[Jon Wilson]

First, everyone please keep mind I confuse easily and it is late...

Second, Jason, please excuse my comments/inquiries if I have not paraphrased you accurately or I am confused and using your statements as to Dallmeyer Patent Portrait lens out of context.

Jason can you, or anyone who else, shed some light on the Dallmeyer Petzval type lens, generally, and specifically the 4D & 5D Patent Lens and their "soft focus" feature.

You [Jason] stated previously in this thread that "the [dallmeyer] lens had a soft focus feature, which by rotating either just the rear element or the barrel (depending on the model of the lens), could be adjusted by inducing spherical aberration by increasing the separation between the members of the rear group." Even looking at the patent diagrams of these lens....it was only recently when I was examining my 4D & 5D lens did I realize there are 2 separate lens groups at the end of these barrel lens.
So then, it is by increasing the distance between those 2 lens in the rear group that the "softness" feature is acheived?

In other threads, I have read where you [Jason] state essentially that you have examined and used many of Dallmeyer Patent lens with the "soft focus" feature frozen/stuck and that the adjustment of the rear cell(s) does not create the "soft focus" effect or at least does not work that well. Moreover, the Patent Portrait lens definitely do not produce a result like one sees in pictures taken with a Verito. Just today, I posted a couple of comparison shots on the Vertio picture thread and found the same to be true with my shots.

I have always been perplexed by the "soft" focus mechanism on my Dallmeyer 4D & 5D Patent Lens. Both have an arrow pointing one direction for "soft," yet despite all efforts to get the "soft focus" feature to move, it seems that it will only move if I remove a small philips head screw which allows the entire rear cell unit (comprising of two separate cells) to move and increase the distance the front lens group and the rear lens group or by leaving that philips screw in place and unscrew only the rear lens cell. BTW, my 4D is a brass barrel lens, while my 5D has an aluminum barrel, and both have iris apertures (no waterhouse slots).

In reading Jay Allen's Portrait/Soft Focus book, he describes these Patent Portrait Lens
and describes the use of this "soft focus" feature is such that it....will render "soft pictures in which there is an evenness of definition without unpleasant out-of-foucs effects."

How were these "soft focus" features on the Dallmeyer Patent Portrait lens actually intended to work? Were they designed to have the small screw removed so as to enable one to actually use the "soft focus" feature or were they designed to so that the two separate rear groups of cells would increase the distance from the two cell groups? If the latter one, then is it worth going to the expense and risk/trouble of having a lens repair guru unfreeze the Dallmeyer Patent Portrait lens' rear lens groups?
If it is worth the expense and risk, which lens repair guru is recommended?

All constructive thoughts/comments are appreciated. Jon

[Jason Greenberg Motamedi]

... So then, it is by increasing the distance between those 2 lens in the rear group that the "softness" feature is acheived?...

Yes. Increasing the space between the two rear elements introduces spherical aberration which decreases sharpness and increases apparent depth of field.

The only way of increasing apparent DOF is by introducing aberrations. In this case spherical aberration appears to spread the depth of field. Here is an quote from Dallmeyer's American Patent of 1867 (no.65729): "... by a slight variation of distance or separation between its elements, any desired amount of spherical aberration can be obtained... With a lens or objective so constructed the operator can, by sacrificing intense sharpness of definition on one plane, distribute the definition over several planes, and so obtain a more artistic and pleasing result."

I have stated elsewhere that this adjustment was orginally designed as way of increasing DOF. It was not designed specifically to be a SF lens. It wasn't until much later that soft focus effect was touted.

... you have examined and used many of Dallmeyer Patent lens with the "soft focus" feature frozen/stuck and that the adjustment of the rear cell(s) does not create the "soft focus" effect or at least does not work that well.

With the original barrel design of the Dallmeyer Patent lenses the SF effect was achieved by reaching through the rear of the camera (removing the GG) and simply uncrewing the rear element a bit. In later models Dallmeyer designed an apparently easier adjustment. The user would simply twist the front part of the barrel. This would increase the distance between the rear elements. However, in time the brass or aluminum in these "improved" barrel seized, rendering the adjustment impossible.

... it seems that it will only move if I remove a small philips head screw which allows the entire rear cell unit (comprising of two separate cells) to move and increase the distance the front lens group and the rear lens group or by leaving that philips screw in place and unscrew only the rear lens cell.

I don't know which style barrel you have. Why don't you email an image to me, that would help me answer your question.

[Jon Wilson]

Jason, attached are several pictures of my 5D Patent Portrait Dallmeyer. It is identical to my brass 4D, except it is an aluminum barrel. It appears to me that the rear set of lens from the outside back toward the barrel total 4 with the lens from the rear back toward the front lens are as follows: convex, concave, convex, and concave. The rear 2 lens will unscrew out completely and the inner two cannot be moved without removal of the small phillips head screw. I am still perplexed how the soft focus mechanism on this designed lens was designed to work. All insights are appreciated. Jon

[Jim Galli]

Jason, attached are several pictures of my 5D Patent Portrait Dallmeyer. It is identical to my brass 4D, except it is an aluminum barrel. It appears to me that the rear set of lens from the outside back toward the barrel total 4 with the lens from the rear back toward the front lens are as follows: convex, concave, convex, and concave. The rear 2 lens will unscrew out completely and the inner two cannot be moved without removal of the small phillips head screw. I am still perplexed how the soft focus mechanism on this designed lens was designed to work. All insights are appreciated. Jon

Jon, it's rare to find one that works. There is a thread unseen at the end of the long tube and when you turned the entire barrel it seperated the 2 rear elements. Almost all are hopelessly frozen now, especially the aluminum ones I think. I have an earlier all brass 3A that is still in working condition. You can accomplish the same thing by reaching into the back of the camera and unscrewing the back element 1/2 or 1 turn.

[Jon Wilson]

Thanks Jim. Upon further investigation, if I remove the small set screw which is on the barrel of this lens, the barrel will rotate which results in the two sets of rear lens (4 lens) to be positioned further from the front lens. When the set screw is in place, then the "soft focus" mechanism is locked into place and all sets of lens are as close to each other as they were designed to be. I will have try some shots to see how the "soft focus" mechanism works. Jon

[Jason Greenberg Motamedi]

Thanks Jim, you saved me a few words.

[Mark Sawyer]

Just bumping a two-year old thread for a clarification: Does the set screw lock the soft-focus movement in place? (So must the set screw be removed for the soft focus to turn?)

[Jon Wilson]

Mark,

As for mine, it did have to be removed on my Dallmeyer Patent 4D and 5D lens to get the soft focus mechanism to work. Without removing the very small screw the soft focus it not turn much at all.
Jon