How to make a sports viewfinder or wire viewfinder?

[photoin.nyc]

It may be a silly question, but just as the title says, I'm curious how can I make a sports viewfinder for my DIY LR 6x17 camera.
I'm using 120 film so the frame is 56mm x 168mm and a Nikkor W 180mm f/5.6 with a covering power of 60 degrees at f5.6.

Any directions would be greatly appreciated!

[Dugan]

You can have one made by cameradactyl...they offer a "Custom Butter Viewfinder" for about $20. It's 3D printed, and mounts into a cold shoe. You tell them the film format and focal length.
I had one made for my custom 6x17 with a 135mm lens.

[photoin.nyc]

Thank you, but I'm trying to understand the math behind it so I can 3d print it myself.

[Tin Can]

The math is geometry

make drawings on paper

angle of view

I use an optical finder on 6X17 but still need to peek at corners which are hard to see

I use simple wire sports finders on some point and shoot

Look at all these designs I like the triple folding ones

and don't miss the geometry image

https://www.google.com/search?q=Wire...w=1229&bih=608

[Tin Can]

more

http://throughavintagelens.com/2013/...e-viewfinders/

[Havoc]

A wire viewfinder is nothing else then a fancy version of the cut cardboard and string "composition aid". Sometimes you see written that people advise you to get a piece of cardboard, cut out the format of your negative and then attach a piece of string. Holding the card at the same distance from your eye as the focal length to compose. Well, you fold a piece of wire the same size of your negative and hold it at the distance of your eye. Make it fancier by adding something to indicate where to put your eye, make it folding etc and you have a wire viewfinder. If you place it closer to your eye than the focal length, then the rule of 3 to get the distance.

[ic-racer]

Just looking at your numbers without the exact calculation, it appears you horizontal angle of view is just a little wider than some normal lens, so a viewfinder for a 35mm lens on a 35mm camera would work. Maybe you can find one on ebay, and mask the top and bottom.

[LabRat]

As a kid, I used to make 'em out of coat hanger wire...

Steve K

[photoin.nyc]

Thank you all! It looks like it's too much headache to make one that can compensate for the parallax and pretty much impossible to match the exact framing...
I'm giving up on this idea but I'm going to make an adjustable phone holder to match the phone's lens with the middle of the place and use a viewfinder app to simulate the exact view of a 6x17 at 185mm. So I'll frame the shot with my phone then lock the tripod and swap the phone mount with my film camera.

Thanks again!

[Havoc]

Thank you all! It looks like it's too much headache to make one that can compensate for the parallax and pretty much impossible to match the exact framing...
I'm giving up on this idea but I'm going to make an adjustable phone holder to match the phone's lens with the middle of the place and use a viewfinder app to simulate the exact view of a 6x17 at 185mm. So I'll frame the shot with my phone then lock the tripod and swap the phone mount with my film camera.

Thanks again!

I'm not going to contradict you that compensation for parallax and exact framing are next to impossible, how are you going to have exact framing and parallax compensation with a phone that is not coupled to the lens? Maybe the lens isn't even the focal length that is printed on it.