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View Full Version : 3d with zoom, also with fixed Scarlet?



Paul Watt
01-11-2010, 07:41 PM
Does anyone know if the fixed lens Scarlet could be used for 3d. Can the lenses be linked that precisely? How are zooms usually controlled in a 3d rig? With gears? Thanks to anyone that knows the answers.

Pedro Guimaraes
01-11-2010, 11:38 PM
the main problem with zooming in 3D is lens decentration. Basically as you zoom the optical center of the lens moves....usually up and diagonally. Some lenses are better than others....some are horrible.

So if you were vertically aligned at 42mm and then zoom out to 16mm on your lens using a wireless lens control system. You would find that you are now not vertically aligned.

It can be done and has been. Alot of times most people won't notice when watching. It will affect and strain thier eyes. Do it enough and people will really start getting uncomfortable. Everyone has their tolerance for geometrical errors. Some people pick up on it right away.

I've talked to some lens tech's that told me they can make some ageniuex lenses "track" together during zooming. This could solve some of the problems with zooming but there are others.......focal length vs. stereobase etc....

So you will probably have to zoom and change the the interocular at the same time to match focal length.......to do this right you will have to map the zoom to the IO position. In fact I believe this is exactly what the guys over at 3ality have developed for the football game coverage etc,,,,

So zooming is not as simple as you might of first thought......it can be done right, and it has! But it can also just be done......it that has been done too! Like I said alot of people won't notice the issues......but do it enough and people will start complaining.

So to answer your original question you could do it with the fixed lens scarlet.....but it would not be advisable. My expirience with RED lenses for 3D is not a good one. Many issues found for 3D use.

Paul Leeming
01-12-2010, 03:55 AM
I see the fixed lens 2/3" Scarlet as the ideal building block for a 3D system, without the need for mirrors etc thanks to the small design size (assuming the lens front diameter is small enough to allow for 6.5cm interocular distance).

I'm fairly certain Red has thought through all these issues already as a true, low cost Red 3D system will sell like gangbusters (and they get to sell double the number of everything!).

I for one would be lined up for at least one such system that can do fully automated, linked lens control along with automatically toeing in appropriately on a baseplate designed for the task.

Fingers crossed it doesn't take too long!

Paul

Stefan Christou
01-12-2010, 04:07 AM
It could happen. And 3D post tools could help with "fixing" the interocular distance if it is not quite 6.5cm and also may be able to help with other alignment issues.

Like you said in your post Paul, the first hurdle will be getting the lenses to be linked precisely with them at the exact same focal length. If that does not happen, nor will 3D on the fixed. But that always leaves the interchangeable and the mini primes.

Pedro Guimaraes
01-14-2010, 05:20 PM
you can't fix IO in post only convergence. You can try to make a large IO more viewable with a few post trix but IO is one of those things you should get right on set.