Canon mount : master - slave lens settings for 3d?

[N.D. Paolo]

I have 2 Scarlets w/ Canon mounts and Canon EF 16-35mm LII lenses, master-slave sunk w/ GigE cable. Iris is slaved, and both cameras auto-focus when master REC button is half-pressed, but, they auto-focus independently.

Hi David,

So, essentially you found it is not possible for a 3D pair of Canon mount Scarlet-X to autofocus on the same point in synch, or on the same point necessarily?

 

[David Cole]

Hi David,

So, essentially you found it is not possible for a 3D pair of Canon mount Scarlet-X to autofocus on the same point in synch, or on the same point necessarily?

They auto-focus independently, but, they each focus properly on the same point in space with the focus SPOT set the same (which it will be by default) or when set to CENTER focus mode (when pointed at the same object thru the beamsplitter). I've been AF'ing on a focus card thru my beamsplitter and the resulting focal length is usually the same in both cameras. From my limited experience so far, I would not recommend trying to operate a stereo rig with only one touch screen, however. Initial configuration of the cameras, media control, histograms, and focus confirmation (at a minimum) REALLY beg for 2 screens.

 

[Les Dittert]

I am awaiting response from the technical guys at Red for info on sync and 3d. I am an engineer and am interested in more info than ' just buy this box and it will work." type of information.
Issues like varispeed in 3d and who is really the master in the setup are some of my queries.

I don't expect autofocus to help much in 3d, as the two cameras are looking at different views thereby often disqualifying a common focus target. Plus the algorithm they currently use seems a bit hit or miss for me so far.
When in 3d mode with a gig-e cable, the focus location should *not* be slaved. Everything else, yes, slave it.

-Les Dittert

 

[Dave Winder]

Hi Les, I can try to field pointed questions for you.

 

[Bruce Allen]

It would be awesome for us if we had electronic lens control for 3D because then we:
- can use cheaper lenses
- can use lighter lenses
- can use a wider range of lenses
- don't have to worry about buying a bunch of follow focus motors that add bulk, weight and price

Obviously, it's awesome for RED too - because 3D requires folks to buy twice the cameras (and due to needing several specialized rigs ready to go... often we need more than twice the cameras!). The cheaper, easier and better they make it to do 3D, the more cameras they sell.

My thoughts are:

1. Canon electronic lens controllers often seem steppy and problematic for motion use. The motors aren't designed for motion use. Birger is the only one I've seen that is actually workable and even that was... difficult! Canon's own C300 doesn't even support it at all. That says a lot: if the inventor of the standard doesn't support it, it makes me think their engineers said "It's always going to be a bit wonky. If we do autofocus, let's make a new EF Movie standard that works properly - and not implement something with existing EF glass that's going to work in a half-baked way - so don't put autofocus on the C300!"

2. RED's upcoming Nikon mount (which has its own focus control motors built in) might be better, no?

3. If RED are still making those FF Electronic Zooms, those would be ideal since they'd be designed from the get-go for motorized cinema use.

Let's assume that at least #3 will work.

Then all we need is either a RedMote Pro that really, really works as well as at least a Bartech - and has some sort of way to match for differences in lenses...

Or we need an open system - so that someone else can develop a controller that plugs into RED's system.

What think everyone?

But for the moment, while we wait for this, RTMotion external motors and controllers are cheap-ish... and seems 3D friendly.

Bruce Allen
www.boacinema.com