3D and long lenses

[Tom Lowe]

Is it more difficult to shoot long-lens footage, at say 300 - 400mm, in 3D? For example, if your intention was to film long-lens wildlife footage in 3D?

 

[David Wilson]

My instinct (from recent experience) is that yes, I think it is more difficult - not by any means impossible, but more difficult. In my experience, almost everything is more demanding with longer lenses, including 3D.

Issues of wanting greater interocular separation also come into play when you are shooting more distance from the subject.

 

[Elsie N]

I've wondered if one used one of those red dot lasers normally used for sighting in a gun for each camera to get the proper spacing, especially on shots that were long range? I don't think they are powerful enough to permanently damage eyes, but one would have to avoid that just the same.

 

[David Mullen ASC]

The 3D IMAX movie "Wings of Courage" shot telephoto stuff with a single camera and copied the same 2D image for the other "eye"... because basically the interocular distance between the eyes doesn't matter when an object is extremely far away, there is no stereo effect in real life with distant objects.

3D photography sort of demands that you work at "normal" subject distances for the most realistic effect, rather than extreme wide-angle and telephoto images that are not like the way people see things. If the whole point of 3D is to create a "you are there" experience, you'd want to keep to shots that seem like they could be a human's perspective onto the scene, even if from extremely high or low angles, etc.

 

[michael zaletel]

David Mullen Rules!



-michael zaletel

 

[Tom Lowe]

The 3D IMAX movie "Wings of Courage" shot telephoto stuff with a single camera and copied the same 2D image for the other "eye"... because basically the interocular distance between the eyes doesn't matter when an object is extremely far away, there is no stereo effect in real life with distant objects.

3D photography sort of demands that you work at "normal" subject distances for the most realistic effect, rather than extreme wide-angle and telephoto images that are not like the way people see things. If the whole point of 3D is to create a "you are there" experience, you'd want to keep to shots that seem like they could be a human's perspective onto the scene, even if from extremely high or low angles, etc.

Is the idea that the farther away an object is, the wider the separation needs to be between cameras? Let's say you wanted to film a crocodile chomping a wildebeest from like 200 feet away, could you build some kind of crazy rig with the cameras spaced 15 feet apart or something like that? Maybe put them on a slider and use laser range finders to establish the distance, as was mentioned above?

 

[David Mullen ASC]

Sure you can change the interocular distance, but then you are making it seem like the POV of a giant if the eyeballs are ten feet apart or something. And it can have the side effect of making the subject look miniaturized.

The thing is that it's natural in real "3D" human vision for distant objects to not have a strong stereo effect, so you just live with the flattening of perspective and depth that long lenses cause, just as they do in 2D movies.

The opposite concept is when the interocular distance is extremely tiny, like for shooting miniatures and making them seem huge. "Coraline" for example had a tiny interocular distance, matching the eyes in a doll's head, so that the stop motion miniature sets seemed real-sized.

So you can play with interocular distances for effect, but you don't want to go too far away from a human's true interocular distance in relation to the subject being viewed, except in cases like I mentioned.

 

[Pawel Achtel]

Is the idea that the farther away an object is, the wider the separation needs to be between cameras? Let's say you wanted to film a crocodile chomping a wildebeest from like 200 feet away, could you build some kind of crazy rig with the cameras spaced 15 feet apart or something like that? Maybe put them on a slider and use laser range finders to establish the distance, as was mentioned above?

As David mentioned there is no perspective difference between left and right eye at large distance and, affectively both left and right images are the same. If you increase interocular distance, then both images will be simply shifted and your brain will not put them together as left and right perspective. There will be no stereo effect.

But, there is an easy solution, which wildlife film makers embraced for years:

Put a normal lens on and get amnong the animals! Makes film making so much more interesting than usual run of the mill fiction stuff (sorry David, LOL) :rofl:

Why do you think I have different assistants on almost every expedition!

 

[David Mullen ASC]

3D sort of demands that you work harder at creating an "immersive" experience by getting a moving camera right in the action, close to the subject, with lenses that are similar to human perspective (I don't mean literally, but anything in the moderately wide to medium focal lengths is fine).

Looking at a distant sunset and using a telephoto lens to enlarge the sunball, for example, is still fine to do in 3D but it's not an "immersive" experience at that point, it's merely a nice shot.

There are plenty of longer-lensed moments in "Avatar" (snap-zooms into objects at a distance, for example) but even there, you can see the stereo-vision effect drop away realistically and the perspective getting flatter.

Enhancing the dimensional effect in 3D is actually similar to enhancing it in 2D -- you move the camera on wider lenses, you have foreground elements to create depth cues, etc.

 

[Hrvoje Simic]

Greatly summed up, David. Thanks.

 

[Roberto Lequeux]

David, what would you do if you didn't have a set built for a kid's bedroom or other small interiors where you wanted a wide master? What lens would be the widest you would use? Could you shoot those anamorphic?

 

[David Mullen ASC]

In 3D? Well, I'm sure you can get away with a very wide-angle lens, it just depends on the amount of foreground, if you are worried about eye strain and distortion. It's similar to 2D, if you have to use a super wide-angle lens, you try to avoid telltale clues that bring out the distortion.

 

[Jim Collins]

Roll is Critical Too

Roll is Critical Too

Another thing that is really important with 3D is that the two cameras be perfectly square with each other. If one image is tilted in relation to the other people will not see 3D. That is one thing that the human brain just can't process.

The further the cameras are apart the harder it is going to be to keep them aligned. IF you are getting them so far apart they have to be on separate tripods it is going to be a real challenge. Then if you have to pan them both and keep them pointed at the same subject it is going to be even more difficult.

But it should be a really fun thing to try.

 

[Roberto Lequeux]

I see. Maybe I should ask in a separate thread since this is the direct opposite side of the equation? Maybe it helps define the differences though.

Aside from this particular scene which I am thinking about, all too often people shoot in very small rooms but need a wide. Like a an actual "normal" non-master-bedroom of about say 12 x 14ft give or take a few, unless you find a rectangular room that gives us some additional space on one side while allowing to easily make it feel smaller by shooting one way.

No foreground is easy to do. For this scene the idea would be to get a large portion of the room and it's decoration, which contrasts with the dire situation the three characters are in. The purpose of the wide is to give a strong sense of where they are in a very quick shot as they run in looking for an important object.

So I suppose something around 16mm might allow for that wide and 18mm might work for the three shots following that wide. Or hopefully 18mm and 21mm on 4.5k?

Would the 16mm look horrible? What about 18mm, best stay away from it too? What might be the rough "OK" wide focal length?

Maybe I should cut and paste this to an other thread. Let me know if anyone thinks I should.

 

[Pedro Guimaraes]

Just got done shooting a whole feature on Angeniuex rouge 16-42.

Most used focal length was around a 20mm. When we needed closeups we just put the camera close to the actors. This resulted in beautiful 3D as everything was very round and volumetric.

Why? Focal length also affects 3d "volume". A long lens will ten to flatten objects a term in 3D we call "cardboarding" you will end up with a image that looks like a pop-up book.

Wide lenses will tend to make things more "round" and give them more "volume".

Also certain focal lengths + certain interocular combination's can result in "giantisim" and "miniaturization". This of course is an effect that can be done on purpose given the proper circumstances. Also if you are forced to use certain combination's there are some tricks to avoid some stereoscopic problems, mostly dealing with camera movement and background relationships.

3D can be tricky......hehe......

Generally wider lenses will be the most used lenses in a 3D filmakers toolbox.

 

[Roberto Lequeux]

Why? Focal length also affects 3d "volume". A long lens will ten to flatten objects a term in 3D we call "cardboarding" you will end up with a image that looks like a pop-up book.

Wide lenses will tend to make things more "round" and give them more "volume".

Also certain focal lengths + certain interocular combination's can result in "giantisim" and "miniaturization". This of course is an effect that can be done on purpose given the proper circumstances. Also if you are forced to use certain combination's there are some tricks to avoid some stereoscopic problems, mostly dealing with camera movement and background relationships.

3D can be tricky......hehe......

Generally wider lenses will be the most used lenses in a 3D filmakers toolbox.

Very interesting.

Watching avatar I felt a bit of the pop up book effect on a few shots in the sky people control room, towards the end of the second act I think. I wonder what happened there.

David, have you shot any 3D tests yet? How soon might we see you shoot something in 3D?

 

[David Mullen ASC]

A 16mm lens in Super-35 is not too bad in terms of wide-angle distortion, particularly if it's cropped top and bottom to 2.40. It's definitely wide-angle though.

The thing about small rooms is to avoid the temptation to use a super-wide-angle lens simply to get a wide shot. It may be better to just shoot in medium shots, or shoot a master framed through a doorway or window, or reflected in a mirror.

Take a look at "In the Mood for Love", which was partly set in tiny apartments in Hong Kong; instead of removing walls (if these were sets), they shot through doors and even through doors and into mirrors to see the action. Yes, there are also wide-angle shots too, but the movie is a good example of working inside small spaces and taking advantage of having blocked-up frames where you only see part of someone.

 

[Roberto Lequeux]

or shoot a master framed through a doorway or window, or reflected in a mirror.

Hehe, yeah baby! I am having fun already!

 

[Pedro Guimaraes]

Hehe...funny you should mention using mirrors David, as we used mirrors a few times during our production. It would make our editor really confused! But we made sure to make ample notations to help him out!

...but yes you make a good point about the use of mirrors. You do have to get creative but really allowed us to get some shots where you never would of been able to put the camera........inside cars especially.

 

[Ketch Rossi]

Is it more difficult to shoot long-lens footage, at say 300 - 400mm, in 3D? For example, if your intention was to film long-lens wildlife footage in 3D?

Well Tom, I love the 200mm 40mm range in both 1.3 cropped sensor as off course in FF, and will be testing the 300mm for some 3D shots for "Rape of a Beauty" this will be extreme close up shots, and some detail shots, as well as some different compositions to see which one works best.

Not yet sure if we will use a fixed Stereoscopic set up or a S3D Rig which will allow both movements of the Interocular distances as well as Divergence.

But long telephoto lenses to my opinion work fantastic on 3D, just as explained here you will loose the 3D effect if shooting long landscapes.

But since all my shots, apart from some buildings, remain in the 5' to 20' so I hope that we get in post what we need for the look I wish to get for this film.