3D Underwater: Gates - 3ality Kelp Forest Filming

[Pedro Guimaraes]

Pedro, this is poor argument because no less than ALL underwater 3D IMAX films except for one were shot with side-by-side systems. Interestingly, the one shot with a beam splitter (The Last Reef 3D) had by far the worst 3D I have ever seen.

Maybe I should of said it differently. "Feature" length meaning 90mins...IMAX movies doesn't count in that case. I mean "regular" 90min movies.....the kind I work on. Even going back decades....Creature of the black lagoon, dial M for murder all were beamsplitter dual camera designs....."naturalvision" and even more recent film history.

I don't work in pure nature cinematography that much (i have before) most of my work is on feature length motion pictures. That means scripts and actors etc....in this world a side by side is less useful and a beamsplitter is 95% or more of you work on most projects.

Everyone like a nice sharp image.....but when it comes to 3D.....too much IA is just about makes anything unwatchable. Nothing makes poeple take off thier glasses faster than too much parallax or volume.....never head anyone say the corners are blurry so I took of my glasses....in fact in many cases due to a shallow depth of feild most of the image is blurry so.....you get my point. Toom much IA is the main factor in my opinion. It's the foundation of "good 3d". of Course there are other factors.....but I see that as the major factor... your free to disagree of course.

As to your statement that both systems are not beneficial to most films....you are very mistaken. Even with your whale movie example, are you going to show people whales swimming in the water in a wide shot for 60-90mins? No of course not.....you will have interviews, topside footage of the researchers and boat work.....not to mention any closer shots of the whales! ALL of that would require a beamsplitter....

So yes.....in every long form project there are many situations where you need the smaller IA of a BS. Even one of a large object such as a whale.

People have a hard time with Panasonic's 2.5" IA of the 3DA1 and other cameras like it.......so I don't think anybody takes you seriously when you propose that your systems 4" IA has a large "application" and use in most productions.

Certainly if you do lot's of wildlife shooting it can be a more usable IA....but for ME and the majority of work i do and I am involved with it's just not that flexible.

Like I said Pawel, you made arguably the highest quality SxS underwater camera system in the world...... but....100mm/4" IA is ALOT.... you did a great job getting it down to that number but it is what it IS.

I am sure it will be used alot....you just can't argue it is something it isn't.

A DTM car is an incredible piece of motorsport machinery it just can't do what a F1 or a Indy car can do. They are different tools with different capabilities and "performance envelopes"

I just have to state the cold hard facts here.

I WISH a side by side system could do what a Beamsplitter system can do.......that is just not REALITY.

I'm done trying to point out the obvious here on this issue.

[Ross Isaacs]

...getting back to the subject, if i may...



Pedro, this is poor argument because no less than ALL underwater 3D IMAX films except for one were shot with side-by-side systems. Interestingly, the one shot with a beam splitter (The Last Reef 3D) had by far the worst 3D I have ever seen.

I agree that ideally you would use both types of rigs (beam splitter and side-by-side) if your subject matter varied in size and distance. However, I would not underestimate the image quality factors (distortions, astigmatism, CA, sharpness, etc..) that greatly attribute to "good 3D" by assisting the brain in fusing two images together. Good 3D is not just IA distance - there are many other important factors.

I would also disagree that using both systems would be beneficial to all films. If you are making a film about whales: a side-by-side rig is the only rig you need. If you are making a film about invertebrates, you probably only need a beam splitter rig for the entire show.

You couldn't possibly make a whale film with just a side by side rig!!!! Especially if you are going to weave a story around them.

[Sean Rawls]

You couldn't possibly make a whale film with just a side by side rig!!!! Especially if you are going to weave a story around them.

Guess it depends on the whale . . . sorry couldn't resist

But thanks for posting pictures and your experiences Johnny: very interesting stuff!

[Pawel Achtel]

You couldn't possibly make a whale film with just a side by side rig!!!! Especially if you are going to weave a story around them.

OK, point taken: I can see at least one shot where beam splitter rig would be absolutely necessary (swimming into a swarm of kril, for example), but the vast majority if not all of the remaining underwater footage, I would be taking with a side-by-side rig.

Topside shots is completely different story: other than scenics, probably all with a beam splitter.

[Johnny Friday]

Well, reality is you would more than likely shoot 2d and turn it to 3d along with use of a side by side rig. At least that is what McGilvary Freeman Films does with many of their films and makes sense on many levels....since it's not only one shot of krill that will be your close shot....however they do this all on 70mm with mark 2 and solido

But if you think it can be done on only a side by side and have done it....please do tell.

[Pawel Achtel]

What were the biggest challanges and was there anything you would like to improve?

The reason I'm interested in your feedback is because I'm now finalising the design of our beam splitter rig and any experiences, whishlist and desired features would help achieve a better product.

How did you feel about size and weight? Depth rating? Image quality? Image distortion? Set-up time? Efficiency? Handling on surface? Handling underwater? Drag? Time needed to change lenses? Any unwanted reflections? Cost to operate?

I'm also interested to know if you shot with 1/4 wave retarder or without and what difference it makes underwater if any.

Is Bob going to write a review, perhaps?

[Jason Goodman]

small correction, Dial M for Murder was not shot with a beam splitter, but underwater sequences on Creature were. Very few beam splitters existed in the 1950's. The Natural Vision system used mirrors, but they were not beam splitters. Wide IA on Natural Vision.

Naturalvision camera used for Dial M, Bwana Devil and House of Wax http://markhardin.com/naturalvision/

Underwater Camera used for Creature from the Black Lagoon http://www.ny3d.org/2009/04/filming_..._from_the.html

Incidentally, not that this is relevant to modern beam splitters, but there is a major density shift between left and right eye in the underwater sequences on any Creature prints I've seen.

[Dave Blackham]

Id be interested to know mirror coatings as they do corrode, also mirror box size as 15mm will be big.

We make our topside mirrors 2% transmissive reflective paths on BK7 glass, specially built. The other question is the guys seem to be getting best results 20 to 30mm focal length much wider underwater and the 3D stage is quite narrow unless your very close to the subject. I like the Nikonus lens approach but I still think 100mm IA is to great in my view to be of use for general use, I realise the limitations of the camera size though.

[Dave Blackham]

What were the biggest challanges and was there anything you would like to improve?

The reason I'm interested in your feedback is because I'm now finalising the design of our beam splitter rig and any experiences, whishlist and desired features would help achieve a better product.

How did you feel about size and weight? Depth rating? Image quality? Image distortion? Set-up time? Efficiency? Handling on surface? Handling underwater? Drag? Time needed to change lenses? Any unwanted reflections? Cost to operate?

I'm also interested to know if you shot with 1/4 wave retarder or without and what difference it makes underwater if any.

Is Bob going to write a review, perhaps?

We do use 1/4 wave topside, but Im unsure how much polarised light is there underwater. Might it just be specula highlights from the surface that may cause issues ?

[Pawel Achtel]

Thanks Jason for the information on the rigs used in Dial M for Murder and Creatures.
Interesting background.

We do use 1/4 wave topside, but Im unsure how much polarised light is there underwater. Might it just be specula highlights from the surface that may cause issues ?

When sun hits a flat surface of the water at certain angles, nearly all light is split into two:

1. Reflected, horizontally polarised
2. Refracted, vertically polarised

The ambient light underwater near the surface is most often heavily vertically polarised.

Interestingly, most cephalopods (octopus, squid and cuttlefish) as well as many jellies use polarised patterns and reflections on their bodies. A cuttlefish can change patterns using polarised signals, so that if you look at the cuttlefish through a glass with vertical polarisation, you don't see the pattern changes, but when you look at it with horizontally polarised glass, you can see them clearly.

Similar to filming a rainbow top-side, for example. If you look at it with polarised glasses, you may or may not see it, depending on the direction of the polarisation.