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Building a stereo 3D rig


Kurt Clark

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I'm trying to build a stereo camera capture rig by following this article https://www.instructables.com/id/How-to-make-a-camera-attachment-to-take-3D-Anaglyp/

In short this is the setup.

image.png
 

Currently my problem is the beamsplitter, so I thought why not use 50% window tint film, I did some homework on it and they said it passed 50% of light that is projected on to it, I thought it is 50% transmissive and 50% reflective, however the seller sent me 20% window tint film which is quite dark than what I'm looking for.

Also the reflective properties as not as good as I intended it to be, seems like window tint film is not the right choice as a beamsplitter alternative, or is it?

Is there any other alternative for the beamsplitter, something that I can make with mirrors etc. that are not that hard to find..

Thanks in advance.

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Professional half-silvered mirrors are expensive. The 50/50 has to be spot on, and you don't want a color cast. Also the film you mention is likely to add distortion to the reflected image. Those, and other, problems will be 'baked in' into your image if you're using one camera. A cheap alternative is the type of mirror used in teleprompters.

That second conventional mirror will have to be front silvered.

Be aware of polarising issues.

You're going to have mega problems with adjusting your mirrors to get a decent line-up, and this rig will get knocked and need readjustment every time you move the camera. You'll need to get the 3D perfect each time you shoot as you won't be able to adjust it in post.

Do you not plan to adjust the inter-axial separation of the cameras? You'll quickly discover that you need to.

Gels. Use gel not colored plastic. The tolerances are much better. You really don't want cross-talk. Rosco are excellent. Get a swatch book and experiment before you commit.

Looks like your setup needs a relatively long lens, and 3D doesn't work too well with long lenses.

I think you're better off with 2 cameras...

I put together a rading list here. http://bit.ly/S3DReadingList The SKY link is a good start. I'm surprised it's still there!

 

Good luck ?

 

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1 hour ago, Karel Bata said:

A cheap alternative is the type of mirror used in teleprompters.

Isn't that a one way or a 2 way mirror, I was thinking about that, and I also saw someone selling a mirror protective sheet for the iPhone, which works similar to the teleprompter mirror, when the iphone LCD backlight is on you can see the screen contents, but when the backlight is off, it will act like a mirror and you can see your own face or whatever is around you in it.

Have a look at this link https://3dvision-blog.com/3983-building-a-very-cheap-diy-beam-splitter-3d-camera-rig/ and the guy uses the iPhone screen protector for stereo 3D, the difference with his setup is that one camera is behind the mirror and one in front of the mirror, so it works pretty well for him. 

In my setup I have the camera behind the mirror, and what I need is the mirror surface facing the camera should be reflecting, for that I would need lots of light on the camera side, but also I want the mirror to be see through, but that extra light on the camera side would just make the mirror reflect and I won't get the see through effect, unless I adjust the brightness of the lights.

So I'm really not sure if a teleprompter mirror is a good fit for this setup, correct me if I'm wrong.

1 hour ago, Karel Bata said:

That second conventional mirror will have to be front silvered.

Agreed! problem is where do I find these kind of mirror's?.

 

1 hour ago, Karel Bata said:

Looks like your setup needs a relatively long lens, and 3D doesn't work too well with long lenses.

By long lens do you mean "Telephoto lens"? Yes you are probably right, I did not initial drawings on the setup and I did some calculations with a wide angle 60 to 70deg FOV mobile phone camera, I had difficulty in getting the image fitting on to the mirrors because of the wide angle, the mirrors were taking a small portion of the final image.

 

1 hour ago, Karel Bata said:

I think you're better off with 2 cameras...

2 cameras, well wouldn't we need to synchronise the cameras then, and therein lies the issue to get both camera's perfectly in sync.

 

1 hour ago, Karel Bata said:

I put together a rading list here. http://bit.ly/S3DReadingList The SKY link is a good start. I'm surprised it's still there!

Thats the most amazing resource you have got on stereo 3D, probably the best there is on the web.

Many thanks!

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