Making a 65deg (diagonal) FoV cold-shoe viewfinder for a 6x6cm MF camera?

[ChrisGalway]

Does anyone have any suggestion for making/adapting a cold-shoe mountable viewfinder for a medium format 6x6cm camera, with a diagonal FoV of around 65deg that shows a square outline for composition? (the "normal" 75mm focal length for 6x6cm is a smaller FoV, around 58deg or less diagonal I think)

I realise I can buy viewfinders that have rectangular formats .. perhaps there is a simple way of taking (some of) them apart and making a new square mask?

Any idea or suggestions welcome.

 

[Dan Daniel]

Not sure about the field of view, but take the viewfinder out of a 126 film camera?

And tape on the front to mask a viewfinder works fine. For example, the Graflex cameras had a viewfinder assembly that had various metal masks to cover the front for various focal lengths, etc.

 

[Philippe-Georges]

Perhaps a used Linhof Universalsucher für Technika as made bij Schneider, could be useful.
This is an 4"x5" viewfinder, which is somewhat close to the 1x1 format (more than the 2x3 35mm format), has a variable angle of view, and will fit a cold shoe.
Perhaps, with some black gaffer tape and trial and error, you can alter the format and then try to 'tune' till you find you wanted angle?
I saw one, although a bit worm, on eBuy for € 89.- in Polen, a bit costly but worth the try?

 

[reddesert]

65 degrees diagonal on 6x6 is about a 65mm focal length. Is that what you have? It would be simpler to say what focal length and format you are using since finders are usually marked/sold by the focal length, not by degrees of field of view. It's also about a 28mm focal length on 24x24 film (cropped 35mm).

There is a 65mm shoe-mount aux viewfinder for the Mamiya Press. It has a field of view for 6x9 and little arrows to indicate a 6x7 crop. You could add a mask in front (or just tape off the edges) to indicate 6x6. The mask will probably be a little out of focus but may be acceptable. You could also do the same thing by masking a finder intended for a 28mm lens on standard 35mm (24x36) down to a square.

If you can find a wire-frame sports finder for 6x6 that adjusts to match a 65mm focal length, that would also work. So far as I know, the Hasselblad sports finder does not go that wide.

There are people who will 3D-print frame finders (no optics) for various combinations of focal length and format, like cameradactyl.com.

 

[ChrisGalway]

65 degrees diagonal on 6x6 is about a 65mm focal length. Is that what you have? It would be simpler to say what focal length and format you are using since finders are usually marked/sold by the focal length, not by degrees of field of view. It's also about a 28mm focal length on 24x24 film (cropped 35mm).

There is a 65mm shoe-mount aux viewfinder for the Mamiya Press. It has a field of view for 6x9 and little arrows to indicate a 6x7 crop. You could add a mask in front (or just tape off the edges) to indicate 6x6. The mask will probably be a little out of focus but may be acceptable. You could also do the same thing by masking a finder intended for a 28mm lens on standard 35mm (24x36) down to a square.

If you can find a wire-frame sports finder for 6x6 that adjusts to match a 65mm focal length, that would also work. So far as I know, the Hasselblad sports finder does not go that wide.

There are people who will 3D-print frame finders (no optics) for various combinations of focal length and format, like cameradactyl.com.

Yes, it's 65mm focal length.


Thanks for your reply and to all the others who have replied with useful suggestions!

 

[ChrisGalway]

Following reddesert's suggestion:

You could also do the same thing by masking a finder intended for a 28mm lens on standard 35mm (24x36) down to a square.

I got a TTArtisans 28mm finder and it masks off satisfactorily. I think the Mamiya 65mm finder would be even better and will wait to acquire one for a reasonable price.

Thanks all for your help.