Reduced Magnification Viewfinder?

[Phil_F_NM]

A few of the recent postings on RFF'ers modifying their Leicas has got me to thinking about the finder in my IIIf.
Since I wear glasses the finder is less than optimal but then again, most are.
My question is has anyone reduced the magnification of the built-in VF in a Barnack body? Increasing eye-relief would be amazing but since there is so little room to work with just a bit less magnification might be enough for a good view of a 50mm lens' field of view.
Going farther than that, has anyone modified their Barnack with a much wider finder? Giving the FOV of maybe a 35mm or 28mm lens? I'm thinking the Voigtlander mini-finder stuck into a IIIf would be amazing if it could be done inside the camera and without making serious exterior modifications. I love using my Summaron on the IIIf but don't like using the crappy 35mm aftermarket finder that I have. I'd rather just have a VF with the FOV of a 35mm or 28mm lens and leave it at that.

Phil Forrest

 

[john neal]

IIRC the VF is just a prism, and it fills the available space in the top plate. Modification would be difficult to say the least.

Why not a separate VF in the cold shoe?

 

[FrankS]

Phil, try a metal CV external viewfinder. They are great.

 

[Phil_F_NM]

The Barnack viewfinders are not prisms, they are reverse Galilean 2 element optics. They have to be in order for the rangefinder optical path to pass across it. This shouldn't be that hard of a modification at all.

I know that some external viewfinders are great. I'm not needing a viewfinder. I'm just thinking of doing this because I can and wondered if anyone else had done anything similar. The idea of a Barnack with a wide angle finder is just cool.

Phil Forrest

 

[ferider]

One thing you could try, Phil, to see if you like the experience, is to hold a Summaron google in front of the VF and see.

 

[john neal]

Phil,

Last one I stripped out (IIIc) was just one piece of glass - is that actually two pieces cemented together?

 

[Phil_F_NM]

The VF of the IIIc and IIIf are made of 3 pieces of glass. The front objective is plano-concave and the rear is plano-convex. Between the two is a prism which guides the light path but offers no effect on magnification. By swapping out the two optical elements in the front and rear with a lesser magnification pair one could create a wide angle viewfinder. The only limiting factor would be finding a VF which has the same length telescope as the one in the Barnack body while also offering optical elements which would physically fit. Shouldn't be too hard to find with the amount of viewfinders out there. Without technical specs for them though, the trial and error could get expensive...

Phil Forrest

 

[Rob-F]

Phil, try a metal CV external viewfinder. They are great.

Now you are talking!

I put the 50mm Leitz finder on one of my IIIfs. It actually underestimates the 50mm FOV. I'll bet the CV is better!

But you know what? Even better is to fit a 35mm CV lens and use a 35mm finder. I use this more than the 50 on the IIIc. And also the 28mm and 25mm! But I digress . . .

Since we have to move our eyes from the rangefinder to the viewfinder anyway, with the Barnacks, there is no penalty in using an accessory finder with the IIIc or IIIf.

My $0.02

Best,

Rob

 

[john neal]

The VF of the IIIc and IIIf are made of 3 pieces of glass. The front objective is plano-concave and the rear is plano-convex. Between the two is a prism which guides the light path but offers no effect on magnification. By swapping out the two optical elements in the front and rear with a lesser magnification pair one could create a wide angle viewfinder. The only limiting factor would be finding a VF which has the same length telescope as the one in the Barnack body while also offering optical elements which would physically fit. Shouldn't be too hard to find with the amount of viewfinders out there. Without technical specs for them though, the trial and error could get expensive...

Phil Forrest

Thanks Phil - we live & learn 🙂