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View Full Version : Advanced Camera Vs. Real Lens?



Giacomo99
04-28-2007, 04:27 PM
I've been fooling around with the new Camera settings, and I have two questions:

1. Does "Real Lens" simulate the spherical distortion that occurs with any real-world lens, or do I need to use "Advanced Camera" for that?

2. If "Real Lens" doesn't include said distortion, what the heck good is it?

EXOSOUL
04-28-2007, 04:51 PM
from what I can understand, it simulates the actual lens on the camera you assign it too. it works for me perfectly so far. so if you want to know what is good for, let's say you are shooting in a live plate and need to comp 3D into it, it will give you a perfect match for the plate.

Giacomo99
04-28-2007, 05:16 PM
I guess the question, then, is: why can Real Lens preview spherical distortion on the fly, while Advanced Camera can't?

jameswillmott
04-29-2007, 05:18 AM
None of the special lenses preview in OpenGL at all. Only simple ones like the Perspective, Orthographic, or any of the perspective correction lenses that are floating around can be previewed in OpenGL.

Salv8or
04-30-2007, 07:37 AM
Is it posible to make youre own lens for the reallens cameras.
I want to match a panasonic camera that is missing in the selections.

jameswillmott
04-30-2007, 07:40 AM
Not yet, but you could write a separate lens shader plugin to do it specifically for that camera ( and any others you have the data for ).

rdolishny
06-11-2007, 12:21 PM
I'm trying to composite some 3D onto vis shot with a Panasonic DVX100A. I think the Panasonic's listed are all still cameras. This ons is a video camera.

I saw a rubic's cube anim somewhere that had some lovely distortion.

I'm using Matchmover which exports a camera mesh as reference I wonder how I can use that to help make a camera.

Right now lens distortion is a dream for now. Any ideas???

monovich
06-11-2007, 01:29 PM
you can also use the surface of a mesh as the camera "lens" and get some controllable distortion.

dpont
06-11-2007, 01:57 PM
You have also this Camera but need a,b,c distorsion
from camera calibration:
http://perso.orange.fr/dpont/plugins/RadialShift_Camera.html

Denis.

rdolishny
06-12-2007, 05:03 PM
you can also use the surface of a mesh as the camera "lens" and get some controllable distortion.

How is this done?

jameswillmott
06-12-2007, 05:11 PM
Model the lens with geometry, apply a UV map, position the lens where you want to view the scene from, and use the Bake Surroundings option in the baking camera.

ghostlight
06-12-2007, 05:25 PM
Lens distortion is a 2D artifact. If you have compositing software, simply remove the lens distortion from the original footage. This is only temporary. Use this undistorted footage as reference when animating.

Render using Perspective camera.

Refering to the value you used to undistort your footage, DISTORT your 3D render with the opposite of that value. Composite over your untouched footage. The distorted 3D render should have bending perspective lines that match that of your original footage.

rdolishny
06-12-2007, 09:41 PM
Lens distortion is a 2D artifact. If you have compositing software, simply remove the lens distortion from the original footage. This is only temporary. Use this undistorted footage as reference when animating.

Render using Perspective camera.

Refering to the value you used to undistort your footage, DISTORT your 3D render with the opposite of that value. Composite over your untouched footage. The distorted 3D render should have bending perspective lines that match that of your original footage.

That certainly sounds like the way to do it BEFORE 9.2, and it might be the way I'll go for this quick project. I upgraded to 9.2 basically because of this (but I've since been blown away with other things) still the camera will take some hand-holding.

"Baking UV camera meshes"? Not for me today! (c:

- Rick

dpont
06-13-2007, 01:03 AM
The RadialShift Camera uses the same algorithm than
many undistorsion tools/plugins included in 2D applications,
I guess that the a, b and c distorsion parameters are
used also in the LW Real Lens Camera, since the PTLens
data base matches the Real Lens list.
http://www.newtek.com/forums/showthread.php?t=68159

Denis.

ghostlight
06-13-2007, 02:22 PM
If Real Lens cameras could let you preview the distortion with Open GL, then they'd be more useful for compositing over live footage. Right now it simply isn't because there's no way to line up your 3D stuff with your background stuff without test renders.

Furthermore, most camera-tracking software relies on distortion-free footage to properly solve the camera motion and geometry of the scene. I undistort my footage before camera tracking, and distort the 3D elements to match in the composite. Works really well.

Check out this behind-the-scenes video:
http://www.ghostlightdigital.com/portfolio/bruinstale/visualeffects/high/

In these videos I don't really go into too much detail about the processes, but you can see the footage being tracked has concave black boarders, showing it has been undistorted and had its boarders expanded. I render for this larger image size with the extra boarders, so that when I distort the 3D elements to match there's no quality loss.

By the way, 9.2 rocks!

rdolishny
06-14-2007, 11:32 AM
Check out this behind-the-scenes video:
http://www.ghostlightdigital.com/portfolio/bruinstale/visualeffects/high/

In these videos I don't really go into too much detail about the processes, but you can see the footage being tracked has concave black boarders, showing it has been undistorted and had its boarders expanded. I render for this larger image size with the extra boarders, so that when I distort the 3D elements to match there's no quality loss.

By the way, 9.2 rocks!

That's a great demo. Syntheyes or Matchmover? ...or call me on it, something else?

ghostlight
06-14-2007, 12:33 PM
I used PF Track, but after trying the demo for Syntheyes..........

rdolishny
06-14-2007, 01:47 PM
I used PF Track, but after trying the demo for Syntheyes..........

Thank you. One last Q. What do you recommend for lens distortion removal? Right now I'm in Combustion using a pinch which seems to be working ... not a lot of feedback it's basically eyeballing it.

dpont
06-14-2007, 02:10 PM
Since you have Realviz Matchmover, you could download
their own utility distoima.exe on their site:
http://forum.realviz.com/realviz/Discussion-MM/distoima-sujet_1043_1.htm

Denis.

ghostlight
06-15-2007, 12:59 AM
After Effects has one, but I use Shake which lets you add or remove distortion vertically and horizontally independently. You could use the one that comes with tracking software, but that leaves your footage undistorted. I prefer to distort the 3D elements to match the footage.

"Pinch" sounds like the same basic idea. I just eyeball it, too. I look for straight lines, get my eye up to the edge of my monitor, and look down the length of the line. I adjust the filter until the line is no longer curved. Then export for much easier tracking.

If you shoot your own material, you can save a filter settings for your specific camcorder. I shoot a grid or brick wall, remove the distortion from that and save the filter settings somewhere. Later, if there's a shot with no visible straight lines (like in a forest) I can just slap on that same filter if I know what lens setting with what camera was used. Shows how useful a Real Lens camera with Open GL preview would be in Lightwave 9.x

Anywayz, that's how I do it. I'm sure there are many others. Cheers!

rman2
06-21-2007, 10:03 AM
ghostlight
im trying to do a distortion to my renders that emules the lens effect, but in many cases i dont have what lens was used. so what tool of shake are you using to match perfectly with the 3d render?
thanks

AbnRanger
06-24-2007, 01:11 AM
I'm using Matchmover which exports a camera mesh as reference I wonder how I can use that to help make a camera.

Right now lens distortion is a dream for now. Any ideas???If you can import the lens mesh, then you have what you need. Proton shows how to use a mesh to make your own custom camera lens in the "ACT custom lenses" tutorial.
http://www.newtek.com/lightwave/videos/

Does that help any, or am I missing your point

ghostlight
06-28-2007, 08:19 PM
If I'm removing lens distortion in Shake without lens info, I use LensWarp to get what should be straight lines in the footage to actually be straight. Stuff on the edges of the frame will be the most bent, so aim for those. I just sit up, get my eye up to the edge of my monitor, look down along the line I want to straighten (like looking down an arrow in archery), and adjust the node's settings until the line looks straight.

Expand the boarders of the shot so it's surrounded by a little black. Track that lens-warp-free footage and render the 3D at that resolution (with expanded boarders).

Later, when applying distortion to your 3D elements, just use the same node but flipped into distort. Should match perfectly. Cheers!