Mamiya Sekor 100mm f2.8 to a graphic view lens board?

[jmarsh]

A real pain in the neck question...

As can be seen in the photos, I have a Mamiya Sekor 100mm f2.8 lens that is attached, in some way shape or manner, to a lens board. I am aware that this is a Press camera lens and covers 6x9 but not 4x5. (I have another of these lenses for use with my Universal, and it does nice work). However, I have a Graphic View 4x5 as well as the necessary Graflok back for 120mm roll film. and would like to give the lens a spin on the Graphic View.

I'd like, if it is at all possible, to fit this lens to a board for use with the Graphic View. I am 100% mechanically inept, let's just say entirely hopeless, so haven't the faintest idea how to detach the board from this lens, or even if it's possible (because I have no idea how the board was fitted to the lens in the first place).

Two questions:

1. Does it appear, to anyone and in anyone's opinion, that this board can be detached, and...
2. Could it be fitted to a lens board for use with a Graphic View 4x5?

Please accept my apologies in advance for what is probably an annoyingly asinine question.

joe

 

[Ian Grant]

Sometimes 100mm/105mm lenses will illuminate the 5x4 screen, that differs from sharp coverage I doubt this will though.

I think it must be relatively easy to mount on a lens board, as it's been done, You might have to make a special lens board to fit a Graphic View.

Ian

 

[Paul Howell]

As Ian said, ought not be much a problem, you need to make or have made a lens board, have it drilled to the correct size, made sure whatever retaining ring that hold the lens in place on current board fits. The 2 images you attached do show the back of the lens so I'm not sure if it's held in place by a single retaining ring or not. If so then I would have a metal board cut and drilled, not sure what it would cost in your part of the world. Then paint mat black. The larger issue is that you have to swap out the ground glass to focus, then remove the ground glass, replace with the 6X9 back to shoot. On the cheap, use 1/4 inch plywood, drill it to size, paint both sides mat black. When I've made lens broads I glued a thin strip of black felt to the outside edges meet the camera to help make sure it's light proof.

The Mamiya press has very limited movements, the Universal none, don't know how much coverage the 100 has in terms of movements. Unless the lens made view camera movements possible then it's likely not worth the trouble.

 

[John Koehrer]

Is the ring at the base of the lens metal or some sort of fiber? And is it the same piece showing on both sides of the board?
The groove across the width of the ring suggests that it may be a friction fit of some sort. The scratching of the ring may be caused by being pushed/encouraged to fit the ring very snuggly.

To be safe, I'd suggest you take the lens to a machine shop and have one of their people look at it.

 

[darkroommike]

Graphic View uses a very standard 4x4 inch lensboard.

 

[Dan Daniel]

Graphic View uses a very standard 4x4 inch lensboard.

I wonder how this compares to the board the lens is mounted to at the moment. You could get a 4x4 board and hack a rough circle in it. Big enough to put the lens and its rings through. Then screw or tape the lens board to the Graphic View board, tape over the joints for light, and give it a test.

A quick hack to see what the lens does before you invest in a clean solution?

 

[Dan Fromm]

Hmm. The original Graphic View's minimum extension is 3.5", ~ 90 mm. Not clear what the GV II's minimum extension is, but it seems to be the same. There are recessed boards for both cameras, but the is no more than an inch deep.

Mamiya Press cameras' flange-to-film distance is on the order of 53 mm.

The 100/2.8 Sekor won't focus to infinity on a GV (either version) in its native mount as shown in the OP's pictures.

I understand the joy of tinkering and of repurposing lenses but this one seems a lost cause.

 

[ic-racer]

Just a guess but it looks like your lens is glued to a horseman 80mm board and you need an adapter to 4" like this
https://www.picclickimg.com/d/w1600...el-adapter-for-RittreckView-Rittreck-view.jpg

 

[Dan Fromm]

ic, what's the point? The lens can't be used on the OP's camera as long it is on a board and in its native mount.

 

[ic-racer]

The lens will work fine at the focusing distances allowed.

 

[itsdoable]

The 100mm f/2.8 shown above is still in it's helical mount, the lens and shutter is attached to the helical with a retaining ring, same as a lens board. I'm pretty sure it'll focus to infinity when directly mounted to a Graphic View board. And you can always use a recessed board if necessary.

You will have to de-solder the sync wire when you remove it from the helical.

 

[europanorama]

For those who have read my wrong message. i meant an RB67-adapter to 180 x180 x4,5mm board. Nothing to do with the problem here. Have found it.

 

[Dan Fromm]

The lens will work fine at the focusing distances allowed.

Right you are. They're from approximately 1:1.5 to much higher than 1:1. I'm sure that's exactly what the OP wants.

 

[iseolake]

It doesn't look so easy to remove. Even if you did remove the current board, you will have to figure out some way to mount a bayonet mount lens onto a board. I would try to modify the current board into something that will fit in your Graphic View. If the Graphic board is smaller than the current board on the Mamiya, then cut back the board. If the Graphic board is larger, then modify a Graphic board so that it could receive the lens in its board. Note that the Mamiya Press flange to film distance is 53mm, I believe.