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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

How to adjust the mm in a 3D Zoom shot?

Lakis Amarantithis said:
Is there a scientific way to adjust the mm to match 100% (not 99%) when you shoot 3d with these lenses? http://www.abelcine.com/store/Angenieux-Optimo-19.5-94mm-T2.6-Zoom/
or any zoom lens?
Click to expand...

The following answer may not be helpful unless your shooting budget is decently large, but it will illustrate the size of the problem.

The best way I know of, and have used, to maintain proper geometrical alignment in a stereo zoom shot is by using the 3Ality TS-5 rig attached to a 3Ality Stereo Image Processor (SIP).

During prep for the shoot you must program rig alignments into the SIP for as many increments of zoom as you have time for. I think we did every 5mm or so on Step Up Revolution. These essentially become key frames in an alignment "animation".

Then, as the lens pair zooms in during a shot, the SIP dynamically realigns the rig using either programmed or interpolated alignment data as the zoom moves along the "key frame curve" you created in prep.

So what I'm basically saying is that your discovery that it's very difficult to successfully use a zoom in a shot in stereo is correct, and it requires a significant amount of technology to pull off decently. And then you'll still have to massage it in post.
 
Keith Putnam said:
So what I'm basically saying is that your discovery that it's very difficult to successfully use a zoom in a shot in stereo is correct, and it requires a significant amount of technology to pull off decently. And then you'll still have to massage it in post.
Click to expand...

And all that trouble to achieve something which breaks a bunch of stereopsis laws.
 
seems like primes with a ken burns scale in is the easier route...i use ken burns fake moves all the time on high res post stuff cuz unless the zoom is spot on its gonna be problematic, 3d just greatly increases the difficulty
 
What Keith said... In short... The CMotion system provides really good matching, but the 3ality system will provide far greater accuracy and even includes backlash correction.

No two zoom lenses will ever be 100% identical, so there's that... But they usually can be matched closer than most primes.

And I would not suggest punching in later. Punching in or zooming changes the 3D effect and an IO change is usually needed while zooming. When you zoom on set you can see what change is needed and make it. Doing it in post is tricky as it might make the 3d unwatchable or you'll need to test beforehand and make necessary changes knowing when you'll punch in later...
 
Hrvoje Simic said:
And all that trouble to achieve something which breaks a bunch of stereopsis laws.
Click to expand...

Can you pls explain what is that "something" and what are the "bunch of stereopsis laws" that breaks, you seem to be extremely pessimistic AND an expert in 3D and 3D laws... So according to you we should never use zoom lenses for 3D??
 
Because heavily breaks the biological effect that makes stereoscopic possible? I have seen the effect done before and anything other than the most subtle push and it is very uncomfortable. Zooming during a shot in 3D just doesn't feel good to experience.

"Creative" cinematography can make a movie hard to watch. "Creative" stereography can make a movie give you a migraine that lasts for days.
 
Just my two cents... you cant "zoom" with your actual eyes, so zooming in 3D makes it hard for the audience to to read/process... not that it can't result in an interesting effect, but Lens zooming in 3D messes with the illusionary sensorial processes required to interpret stereoscopic 3d, so it can make it hard to watch.

Its like a bad layered composite... if an element that should be in sharp focus is NOT in sharp focus alongside its other similarly placed companions, your brain gets confused, and can distract from the main content. again... not that it CAN'T be done/used, but it might not result in the intended cinematic effect.
 
Lakis Amarantithis said:
Can you pls explain what is that "something" and what are the "bunch of stereopsis laws" that breaks, you seem to be extremely pessimistic AND an expert in 3D and 3D laws... So according to you we should never use zoom lenses for 3D??
Click to expand...


Yes dont zoom, 3D is bad for the eyes as it is... :)

No but seriously, to me and many others, zooming during a 3D scene really breaks the 3D feel... using zoom lenses to be quick to move from one framing for one shot to a different focal length for another shot is ok I guess.

But then again name one 3D film that you liked where they use a lot of zoomins during shot and where they used a huge variety of focal lengths....

Basically 2001 / Gravity kind of scenery and camera work suites 3D, long clips wide lenses, and no zooms.

But thats all what could go under taste so each has it's own ofcourse.

So to me if I would make a "unwritten list of stereoscopic rules" then no zooming would come quite high on that list... But I'm a bit conservative I don't even want things to come in between the camera and interest point.
 
I did a zoom compression / zolly / contrazoom whatever you want to call it, in Julia X 3D in 2009 using a C-motion system and it is very subtle and totally successful. A 3ality system is not necessary to synchronize zooming, focus or iris for shooting in 3D. Like most things in 3D, if done properly it will not hurt your eyes. The 3D camera is not analogous to the human eye brain and a 3D movie is not a recreation of stereoscopic sight. Your eyes cannot change focal length from shot to shot but our brains are able to sort out this phenomenon in 3D movies without a problem. 3D imaging is a complex illusion and like any other, if you understand its capabilities and limitations, you can take your audience right up to the edge of that illusion but no further. It is definitely very easy to screw things up and get a result that hurts the audience, but then again if shooting 3D properly were easy, everybody would be doing it.
 
Lakis Amarantithis said:
Can you pls explain what is that "something" and what are the "bunch of stereopsis laws" that breaks, you seem to be extremely pessimistic AND an expert in 3D and 3D laws... So according to you we should never use zoom lenses for 3D??
Click to expand...

In short.

Your brain interprets depth and achieves spacial navigation through fixed factors.
Those factors are directly related to:
a) Human Body, its form and its senses, with their biological and physical properties
b) the environment with its light/space properties.

Brain has been developing and tuning to this multitude of internal and external factors for decades, ever since the first ray of light entered the eye of a baby. After the head stops growing brain continues to perfect its "spacial calibration". Which is why you don't see many top shooters/marksmen around puberty.

If your legs were changing length during walking your walk would be a challenge. If they did that during running you'd fall down.
If your ears changed size or shape throughout the day you'd have trouble distinguishing sounds around you.

This has nothing to do with pessimism.
It has to do with reducing this stereography mess.

And yes, I'd also suggest ditching zooms and faked depth in telephoto.
It is a complete f@#&%*g visual mess and a circus. What is missing is a bearded lady and Siamese twins.
And more cowbell.



Hope this helps. I suggest not interpreting this personally.
Hats off for creative thinking and good vibes to you.
 
There have long been staunch proponents of pure, technically accurate 3D, or orthostereo as it is sometimes called. To create a truly accurate recreation of a 3D scene, and an orthostereo viewing condition, there would be only one lens choice, only one viewing position and a lot of other severe technical and artistic limitations. In combination, they make such a pursuit a non-starter, for real. Precision activities like surgery, aerial refueling, telepresence robotics or sharpshooting may require this accuracy, and definitely would be negatively impacted by small alterations in stereo space, scale or perception. Making and watching motion pictures is about exploring the fantastic and the fictional through interpretive and creative means. The process inherently requires that we do things that do not adhere to reality or even physics sometimes. Stereo viewing does have some hard stops in terms of what will work and what will not work, but it is more flexible than some posts would lead you to believe. Even though your eyes cannot physically do a zoom compression shot, it has and will work in a stereoscopic film and it can absolutely be done in a way that causes no pain or discomfort, but gets your audience to think, "wow, I've never seen that before!"
 
>>Hope this helps.

Every idea/suggestion helps.

>>I suggest not interpreting this personally.

Not by far. Indeed I am very thankful for you reply. We all here to help each other to the degree we can.

I however strongly disagree and I look at this with another perspective.

I did many 3D shots (with the Sony HD-10 and also with it and the Cyclopidal 3D tele adapter - fantastic product) and they looked really good, I can even say perfect.

Because the technology is primitive today in 3D I can't see a system that will converge plus focus plus zoom say a 300-800mm lens today. I did this manually few days ago with the Dragons and looks FANTASTIC in a big 3D screen. I'll be happy to provide assistance to anyone developing a complete system. Manufacturing is not my thing.

I firmly believe that we are at a time that machines become better than us and all of our organs. That includes our eyes, our 3D perception and everything else big time.

With proper use of lenses and cameras I believe that today for first time you can produce 3D worth seeing. As there is not a standard it's the wild west law. Hugo has much different 3D than Avatar than Hobbit but all look awesome to me.

Furthermore I believe that 4D will play huge in the near future.
 
Keith Putnam said:
The following answer may not be helpful unless your shooting budget is decently large, but it will illustrate the size of the problem.

The best way I know of, and have used, to maintain proper geometrical alignment in a stereo zoom shot is by using the 3Ality TS-5 rig attached to a 3Ality Stereo Image Processor (SIP).

During prep for the shoot you must program rig alignments into the SIP for as many increments of zoom as you have time for. I think we did every 5mm or so on Step Up Revolution. These essentially become key frames in an alignment "animation".

Then, as the lens pair zooms in during a shot, the SIP dynamically realigns the rig using either programmed or interpolated alignment data as the zoom moves along the "key frame curve" you created in prep.

So what I'm basically saying is that your discovery that it's very difficult to successfully use a zoom in a shot in stereo is correct, and it requires a significant amount of technology to pull off decently. And then you'll still have to massage it in post.
Click to expand...

3Ality did an amazing job with the SIP. I really hope to have the great fortune to work with it soon. However what you do in a run a gun situation? The best footage in the world is in the most inaccessible locations! The cameras with an 120ex tripod are bulky enough.

Massaging it in post will be a pleasure for me.
 
That's an excellent tip, especially with the real estate the Dragons give you.
At least you can run and gun cheap.
Thanks!
 
Chris Burket said:
What Keith said... In short... The CMotion system provides really good matching, but the 3ality system will provide far greater accuracy and even includes backlash correction.

No two zoom lenses will ever be 100% identical, so there's that... But they usually can be matched closer than most primes.

And I would not suggest punching in later. Punching in or zooming changes the 3D effect and an IO change is usually needed while zooming. When you zoom on set you can see what change is needed and make it. Doing it in post is tricky as it might make the 3d unwatchable or you'll need to test beforehand and make necessary changes knowing when you'll punch in later...
Click to expand...

I shoot 3D changing the IO manually and came fantastic. I agree with testing. Many variables in consideration.
 
Jason Goodman said:
I did a zoom compression / zolly / contrazoom whatever you want to call it, in Julia X 3D in 2009 using a C-motion system and it is very subtle and totally successful. A 3ality system is not necessary to synchronize zooming, focus or iris for shooting in 3D. Like most things in 3D, if done properly it will not hurt your eyes. The 3D camera is not analogous to the human eye brain and a 3D movie is not a recreation of stereoscopic sight. Your eyes cannot change focal length from shot to shot but our brains are able to sort out this phenomenon in 3D movies without a problem. 3D imaging is a complex illusion and like any other, if you understand its capabilities and limitations, you can take your audience right up to the edge of that illusion but no further. It is definitely very easy to screw things up and get a result that hurts the audience, but then again if shooting 3D properly were easy, everybody would be doing it.
Click to expand...

Could not possibly have been said better.

I recognize you as one of the ealry leaders in the 3D revolution. I really like to see Julia X, I looked at it at the Hollywoodreporter.com, where can I buy it? Pls pm.
 
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