Stereo camera to tilt or not to tilt

[johnielvis]

I think tilt would be a benefit. There is NO perspective distortion using tilt--keep the BACK level and straight and you can do whatever you want to the front, as long as the SAME thing is done to both lenses. Try it out first using a view camera with a shift bar. The tilt on both (just hinge the front with both lenses at the bottom to allow this---same hinge--the lensboard should hold both lenses) will allow you to get more foreground in focus--you can use less stopping down to get some subjects in focus. Try it and you will see. Tilt changes only the plane of focus and has nothing to do with perspective.

OH--as for usefulness...only for when you want far away and VERY close in exact focus--this is only really needed with larger formats--the smaller formats--shorter lenses--they will have enough depth of field.

to tell the truth--building a camera is a real undertaking--lots of things to get working--I'd make it as simple as possible first (no tilt) and then ADD the tilt facilty later---should be an easy add.

I'd advise to build it first...THEN add the doo dads later AS NEEDED--the simpler the lighter and more rigid.

[himself]

I think tilt would be a benefit. There is NO perspective distortion using tilt--keep the BACK level and straight and you can do whatever you want to the front, as long as the SAME thing is done to both lenses. Try it out first using a view camera with a shift bar. The tilt on both (just hinge the front with both lenses at the bottom to allow this---same hinge--the lensboard should hold both lenses) will allow you to get more foreground in focus--you can use less stopping down to get some subjects in focus. Try it and you will see. Tilt changes only the plane of focus and has nothing to do with perspective.

OH--as for usefulness...only for when you want far away and VERY close in exact focus--this is only really needed with larger formats--the smaller formats--shorter lenses--they will have enough depth of field.

to tell the truth--building a camera is a real undertaking--lots of things to get working--I'd make it as simple as possible first (no tilt) and then ADD the tilt facilty later---should be an easy add.

I'd advise to build it first...THEN add the doo dads later AS NEEDED--the simpler the lighter and more rigid.

all that is what I thought in the first place. but it's good to have it confirmed.

I've already built a full movements LF camera, so the actual building will be no problem and I'm not that worried about it - so I was really just hoping for confirmation that sticking a tilt on it won't cause any problems after the fact you know, especially because building the bellows is a bit of a pain.

[Old-N-Feeble]

I say "try it" without bias from any previous information.

[himself]

there is one thing I just thought of, how will the front tilt over or under the "wall" separating the 2 images... I don't fancy making 2 bellows

[johnielvis]

2 bellows is the cadillac way--OR you can just put in a septum divider toward the back--the divider only has to be big enough where one of the 2 views doesn't "see" the other lens--or, should I say--the light from the other lens--if it sees the lens but there's no coverage (vignettted) then it's not a problem---size the back divider based on the closest focus distance--anything closer will have the lens closer into the divider and provide ample "shading" is guaranteed...

draw it out on a piece of paper and you shall see.....

[himself]

so there wont need to be a complete (as in, like totally complete) separation of the 2 sides?

[johnielvis]

nope---in fact every portrait camera I've ever seen has just the rigid dividers in the back---so too the olde tyme multiple picture portrait cameras too---the thing is you can't fold it flat without taking out the divider (that is, you can't collapse the bellows all the way if there's a rigid divider in there) AND a shorter divider will limit your bellows draw for close ups...it depends on the lens used.....and the front movements too now...if you are shifting the front lenses, that will move the cone of light....

you may just want to make an attachable BACK for your existing camera with the dividers installed--the dividers would extend INTO the existing camera bellows space--then use special front "double lens" boards--then you can have a stereo conversion kit with full movements

most of these things had a single bellows with a septum down the middle--you don't need COMPLETE light SEALING--just a divider to keep the light from one striking the other and getting a double image---unless you want a hipster type double vision camera....

[himself]

the lens board on my build isn't big enough to accommodate 2 lenses sadly.

my original thought was to use 2 short lenses, like maybe 60mm off an old folder (focus on the lens rather than the bellows), so I never intended to have a collapsible camera anyway. maybe now that I'm going to use tilt I'll go for half and half and only put the wall in the hard part.

[TimFox]

I use view cameras, and often use tilt/seing and rise/shift. I almost always use rise.
To keep the perspective constant, you keep the film plane vertical. Shifting left-right or rising up-down (either or both the lens and film) changes the region mapped onto the film plane.
Tilting the lens board with respect to the film plane changes the plane of best focus, but does not change the perspective. It may change the exact region mapped onto the film plane, depending on the tilt axis. This is typically done to keep the meadow in front of you and the snow-capped mountain in the background in focus, allowing some defocus where the mountains reach the ground.
If you tilt the film plane, you do change (or distort) the perspective. If the film plane is tilted backwards, for example, the vertical parallel lines on skyscrapers will converge on the film.