Multigrade filter holder for Focomat 1c

[Susie]

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I recently got my darkroom up and running again, and bought a new set of Ilford filters which go under the lens.  Unfortunately, as noted here and elsewhere, the Ilford holder does not fit on the Focomat 1c.  There have been several suggestions on how to get round this, the most elegant being the Leitz New York holder.  Not having one, and being unlikely to get one, I have made my own: details below:-

First a piece of brass sheet was marked out and the large hole made.  A series of 60 holes 3/32" diameter wered drilled just inside the marked circle:

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and then the profile cut out with a hacksaw and filed to the markings:

 

The sides were bent up, a pillar turned from brass bar and a screw turned from steel.  The filter holder was then sparyed with matt black paint and the screw oil blackened.  The notch in the pillar is to clear the snug that restricts the movement of the original red filter holder.

With a black washer under the screw head, it was fitted to the Focomat:

 

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[M.Hilo]

Bravo!!!

It is wonderful you took the time to do this. And you did very well. I have the original and I have several modified filter holders. It is particularly nice you also made the special 'longer' shoulder screw.

Now you need to use it for a while. Because, if there's anything to improve, you could do that. I have only one small 'minus' about the original holder. The high flaps do not make it easy to change filters when the enlarger head is way up, for large printing.

I have also thought for a long time the original holder was made in the USA. And maybe it was. However, in the meantime, this holder has surfaced in a German Leitz catalog. Not only for the Focomat Ic, also for the Valoy II. For the latter, the attachment system is different. Image attached.

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[Susie]

Thank you for your comments.  I have already realised that a modification is in order - and you have mentioned it!  The small flap on the right could do with being only half-high, which would make the insertion of the filters easier.  At the moment they are all 10mm, so I'll cut just that one down to about 5mm.  It does mean though that I'll have to touch the paint up, which will be a bother.

The originals look to be stampings and that for the Valoy ll is basically the same.  The only difference is that the mounting bracket is rivetted on rather than having the hollow pillar and screw.  The little bracket looks the same as the one that holds the red filter.  I have a Valloy ll as well, but it is usually set up as a copy stand using an OOTGU Focoslide, my M9 and a home made lighting unit.

I suppose the way forward these days is to have someone who is a wizz with CAD design a holder to be 3D printed.

It is some while since I last did any photographic machining.  At one time I used to make quite a lot of lens mounting flanges for large format cameras, but the high cost of brass plate put people off.  At some point I really want to convert my 400/6.8 and 560/6.8 Telyt lenses to fit a Visoflex 1 but I cannot work out how the bayonet mounting comes off!

[M.Hilo]

You could indeed shorten one, or even two flaps to 5mm. But I would try this design for a while first. Since I found the original holder for the Valoy II (last year), I use it a lot and I don't struggle anymore. I have loose flexible filters. For prints up to 30x40cm, there is no problem. Going bigger, it's still fine, but I have to be more careful.

Yes, Leitz just used the original Valoy II red filter mount, which makes sense.

A friend and I designed a modified version of this Leitz filter holder (for the Ic and the Valoy II). CAT to 3D and we had some plastic prototypes made. We included lowering the flaps, or maybe even omitting the front flaps, in this design.

But we both lost interest because our main goal was to be able to print. We could do that, using the original Leitz holders or modified holders from other brands. The Omega holder in particular, is great because it is 'open' at the front, and adapting it to the Focomat Ic or the Valoy II takes 5 minutes.

I am happy to share these designs with you, or anyone else. Just send me a pm. Your comment about the Telyt lenses to Visoflex, I will pass on to a friend who may have something to say about that.

attached a sketch of the modified Leitz holder

 

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Edited May 27, 2023 by M.Hilo

[zeitz]

16 hours ago, Susie said:

At some point I really want to convert my 400/6.8 and 560/6.8 Telyt lenses to fit a Visoflex 1 but I cannot work out how the bayonet mounting comes off!

 

6 hours ago, M.Hilo said:

Your comment about the Telyt lenses to Visoflex, I will pass on to a friend who may have something to say about that.

Susie, you are right that it is not obvious how the 400 & 560 f6.8 M mounting tube comes apart.  I believe the bayonet mount in a more complex part that extends into the tube itself.  (By the way the tube for the Leicaflex R has an easy to remove mount, so it may be a better starting point.)  I think the disassembly has to start from the front of the tube, but that is pure speculation on my part.  You have two challenges for this conversion.  The first is to make a 39mm 26 tpi male mount for the tube that replicates the originals' front end, and the second is to remove 22.5mm from the length of the tube to preserve infinity focus.  (Starting with an R mount will require length more to be removed.)

Your machining skills are impressive.  If I were to attempt such a conversion, I would give the problem to S K Grimes, a machine shop for photographers in the US.  This company has made very complex parts for me at very reasonable prices.

[Susie]

Hi Zeitz,

Thank you for the sugestions.  I have used Grimes in the past for mounting lenses into modern shutters, and have aways been impressed with their service, but I am confident that this is something I can do; after all I have the kit, and a suitable piece of high grade aluminium to do it.  As to infinity focus, at the moment it goes beyond that, and there is plenty of movement in the trombone slide.  I also want to make and fit a tripod mount nearer the centre of gravity.