3D Set up

[Jawad Mir]

I am looking to get into 3D set up using DSLR cameras. I could be wrong but I have seen people put 5Ds side by side on a slider that has two brackets.

Anyone can help me out on finding these DIY sliders or something else that allows me to lock the tripod in one position

Thanks


Jawad

[Giroud Francois]

All the problem rely in the distance between the two lenses (interocular distance).

The more you get the more the stereoscopic you get, but also the farthest you need to keep the subject from the camera.

So probably if you want to use 2 DSLR with a workable distance, you will need make them closer as the body allows.

There are several ways to mount the lens closer, all of them will use at least a mirror (surface mirror)

The easiest way is to mount one camera looking straight to the subject and add a 45degree mirror looking on the side.

[Chris Hurd]

Originally Posted by Giroud Francois

the distance between the two lenses (interocular distance).

The distance between the two lenses is the interaxial distance.

Interocular is the distance between two eyes, which is not the same thing as the distance between two camera lenses.

[Giroud Francois]

yes, but for big screen you better to make sure you do not end up with a distance between the 2 pictures bigger than the interocular distance (about 65mm, or your eyes will need to diverge to accomodate both picture)
So making sure your interaxial distance is at least smaller than the interocular is a safe way, or you will ned to converge your lenses.
big interaxial is ok as long you limit the viewing on samll screens

[Tim Dashwood]

Originally Posted by Giroud Francois

yes, but for big screen you better to make sure you do not end up with a distance between the 2 pictures bigger than the interocular distance (about 65mm, or your eyes will need to diverge to accomodate both picture)

True. The is the maximum positive parallax for the display width. Our brains can accommodate slight divergence, but the angle of divergence is worse the closer you sit to the screen. Therefore, as you stated, you shouldn't exceed the human interocular for on-screen positive parallax.

Originally Posted by Giroud Francois

So making sure your interaxial distance is at least smaller than the interocular is a safe way, or you will ned to converge your lenses.
big interaxial is ok as long you limit the viewing on samll screens

It is safer to use smaller interaxials as a general guideline but the interaxial never directly relates to the projected positive parallax separation. There are many more factors involved like real-world depth bracket, desired depth budget (aka parallax budget), convergence point and focal length. Smaller interaxial distances capture less "depth" in the scene so it is easier to fit within a depth budget and manipulate the convergence in post.

However, there is a scenario where the opposite logic is true. Most of the IMAX 3D films were shot with the Soledo camera which has an interaxial close to the human interocular. This created a lot of depth but the convergence was usually set at or near infinity (no divergence in positive parallax) and the screen was so big with a 70 to 90 degree angle of view (depending on where you sat in the IMAX theatre) that stereo window violations were not a concern. Those IMAX 3D films look great on the gigantic IMAX screen, even though there is some miniaturization effect. The problem that you will notice when these films are converted to Blu-Ray 3D for the small screen is that we now have to deal with a very visible stereo window and depth budgets that are usually too deep to simply converge on the closest object and still be within positive parallax limits.