general Q: how wide of a lens on S3D, & still OK to watch ?

[Les Dittert]

I have a general question :
How wide can you shoot S3D before the image becomes uncomfortable or otherwise undesirable to view?
Mostly in outdoor architectural and or scenic 'big' shots, with some people in view as well.

I don't have experience with this, but I'm thinking that because on a smaller screen especially, a wide FOV lens would be capturing much wider than the display is showing, causing strife.

I know fisheyes would be out, but what about ultra wides ?

-Les

 

[Ketch Rossi]

In 3D using a Beam Splitter rig, you can go as wide as your MB (Mirror Box) allows you to before Vignetting.

So this means an 18mm, on some, 16mm on others, and a maximum of 14mm on the largest MB, absolutely no issues in viewing.

 

[Les Dittert]

Ketch,
Thanks for that info. So if I'm on a SBS rig, where do you think the limits are ?
I'm worried about the 3d 'effect' being lost or falling apart due to the image captured being way more field of view of the display system.
-Les

 

[Ketch Rossi]

Most welcome Les,

there is no such a worry as in 3D the wider the better (within limits of distortion free images) and of course the lenses capturing seen other..

However I have not tested a side by side on the wide end, as SBS to me is only for Super far away placement of the cameras were Super telephoto Lenses
are used and the camera really many feet apart form each other, for everything else I use Beam Splitter.

 

[Stacey Spears]

I have been shooting 24mm and 35mm in a SxS rig. I am also shooting 5K FF, but framing for 16x9, which ends up 4800x2700. This gives me room to adjust in post. Distance between center of lenses is 5", so. My nearest object is 12'5". I have also shot as far apart as 24" for some hyper stereo, but have not looked at those results yet.

 

[Keith Putnam]

So if I'm on a SBS rig, where do you think the limits are ?

On a recent S3D feature we did quite a few shots on a side-by-side rig (with an IO of about six inches... basically getting the Epic bodies touching) with 9.8mm Kinoptik lenses. We did this for the reasons Ketch suggests above: no practical beamsplitter box will allow a 9.8mm field of view. But anyway, more to the point:

With 9.8mm lenses at an IO of about 6 inches and cameras essentially parallel we found that the closest an object could get to the rig and still have a fuseable stereo image was about ten feet. If you're planning on using very wide lenses on an s-b-s rig just be aware that the larger your IO the further away your nearest object must be to be fuseable.

As your lens gets wider (i.e., as your field of view gets wider) you require less deviation to achieve the same amount of apparent depth. This correlation will continue as wide as you want to go, and that's why many stereographers prefer to shoot 3D with wider lenses than DPs would choose for 2D; more depth, less eye strain. Now, your real problem will be dealing with the distortion characteristics of your very wide angle lenses and achieving alignments which remain acceptable across the entire frame. Our 9.8mm shots will require some fairly extensive geometry correction in post because, among other issues, those lenses' distortions just don't match each other precisely.

Your concern about a wide angle field of view being "wider" than a display is baseless. Don't worry about it. If that were true, everything we watch would have to be precisely 1:1 macro photography with precisely life-size image display. Stereo principles apply no matter what the size of the display is. The amount of an audience's field of view which is occupied by a stereo image does have an effect on the 'roundness' of the 3D, which is to say that the same stereo image viewed on a large and small display from the same viewing distance will result in the image on the smaller display appearing 'rounder', sometimes to the point of exaggerated distortion. But audiences usually self-tune for this by sitting closer to small displays and further from large ones.

I hope this helps.

 

[Les Dittert]

fix it in post

fix it in post

OK, that's great. I will be using SLR glass for this, and I also plan to warp and align the images in post.
If I can get the IO down to 4" , I would be thrilled.
Since the Scarlet doesn't have features I like kick in until the 3K crop, I'm considering the Sigma 8-16 lens.
It has higher MTF (photozone.de tests) than the Tokina but is slower.

Vignetting and CA ? I'll add that to the post processing, we are not dipping cow hide extract coated plastic in pools of chemicals any more :wink5film), let the IT clean it up , I say!
-Les

 

[Keith Putnam]

4 inches may be difficult to achieve, as the Scarlet body isn't much smaller than the Epic body and putting two Epics side-by-side so the bodies are touching gives you about 5 1/2" between the center of the lens mounts. Best of luck!

 

[Stacey Spears]

Keith, I am getting 5" with room to power on left epic with a small tool. With them touching, I get closer to 4.5". If I removed the the SSD, I might get 4". I am using Nikon 24mm F/1.4G primes.