Composing pinhole photos

[robopro]

I've been using an 11X14 cardboard box camera I made several years ago modified to use glass plate negatives. One problem I've had is in accurately composing the scene as there is no viewer as in an SLR. Sometimes I get lucky, and sometimes I don't. Now I'm designing a better variable focal length camera and would like to incorporate some way to 'preview' what the negative is going to see. Anybody have any ideas on how that can be done?
I thought about using a ground glass, but I'd have to use a larger pinhole to get enough light in to see the image, and I'm thinking when I then change to the smaller pinhole for the photograph the angle of view would also change.

[keithwms]

Changing the size of the pinhole won't change the field of view, but changing the distance from the hole to the film will, of course.

Perhaps you could just mount a regular external VF, that will at least give you some ability to center your composition, and if you get a wide enough one you might be able to make some marks to indicate approximate edges. You could even get a zooming viewfinder (e.g. the horseman one) , but they are very pricey.

[Roger Hicks]

I've been using an 11X14 cardboard box camera I made several years ago modified to use glass plate negatives. One problem I've had is in accurately composing the scene as there is no viewer as in an SLR. Sometimes I get lucky, and sometimes I don't. Now I'm designing a better variable focal length camera and would like to incorporate some way to 'preview' what the negative is going to see. Anybody have any ideas on how that can be done?
I thought about using a ground glass, but I'd have to use a larger pinhole to get enough light in to see the image, and I'm thinking when I then change to the smaller pinhole for the photograph the angle of view would also change.

An external VF (including a simple wire frame finder) is almost certainly your best bet. The wire finder will be self-adapting if you put the frame on the front of your camera and the eyepiece on the back, so the separation varies with the 'zoom' in focal length.

But there's still a certain amount of luck involved...

Cheers,

R.

[John Bartley]

My suggestion would be to use a set of "peep sights", somewhat like what you would have had on your .22 when you were kid out shooting groundhogs. Put a rear sight on each rear corner of the plane of film and put the front sight in the centre front right over the pinhole. Sighting each corner to front one at a time will give you the field of view. Do the same thing for the vertical.

[Joe VanCleave]

I have installed "viewing dots" on the sides and top of my various pinhole box cameras. These should protrude slightly above the box's surface. The idea is to have the front dot adjacent to the pinhole, and the two rear dots adjacent to the edges of the negative as positioned in the camera. Then by sighting along the dots you can get a fairly precise idea of the horizontal and vertical extent of the image field.

Others do this in a similar fashion using lines instead of dots, but with a telescoping box camera of variable focal length, the dot idea should work fine.

[robopro]

Very good ideas! Something for me to think about. John, how did you know I used to shoot groundhogs with a .22? :-) Local dairy farmers used to pay us kids a buck each to get rid of them... cows would step in the holes and break their legs.

[eddie gunks]

i kind of eye ball it. i set it up and then look at the hole and the basic direction. most pihole camreras are built on the wide side. i guess for me it helps that i just shoot lots and lots of pinhole images, so now i got a pretty good idea. some of the fun of it is guessing it and seeing the results. here is one shot that i miss judged a bit just yeterday.

i found that i used so much film in my 4x5 pinhole camera that i perfected loading/developing/and composing sheet film. it has really helped me in my view camera shooting too.

eddie

[robopro]

OK, I had this crazy idea that if I incorporate a film holder specifically designed to hold a ground glass, then I could 'dial in' a larger pinhole and (if I leave the back of the camera open) then with a black cover I could view what the camera will see, then 'dial in' the hole size needed for the focal length. Remeber, this camera will be both variable focal length and variable pinhole size.
Sounds like a great idea, but for now it's all still on paper. If anybody knows of a technical reason why this won't work I would seriously love to hear it, because sometimes the greatest ideas on paper don't work in the real world...

[Joe VanCleave]

Robopro, I do this with my Speed Graphic, where I use the ground glass with a ~1/4" aperture plate up front to compose, then switch to the main pinhole + shutter lensboard to make the exposure. Not a crazy idea at all, works fine.

The 1/4" size viewing hole is large enough such that a daylight landscape can be easily viewed under a dark cloth, and still see enough level of detail to adjust for composition. Focus, of course, is a non-issue with pinhole, so your view screen built into a used film holder doesn't have to be *exactly* at the same lens-to-film distance for it to work.

[robopro]

Cool! Thanks!