Re: "real" cameras in xsi

["Greg Smith" <greg(at)stanwinston.com>]

typically with digital camera's your filmback is your sensor size. Now I think matching the focal length is a bit tricky with digital video cam's.

 

Here's a page that shows you the sizes of traditional film filmback sizes

http://www.panavision.com/aspect_ratio.php

 

here are some links on ccd sensor sizes

http://www.dpreview.com/learn/?/Glossary/Camera_System/Sensor_Sizes_01.htm

http://www.edmundoptics.com/TechSupport/DisplayArticle.cfm?articleid=290

----- Original Message -----

From: Gene Crucean

To: XSI(at)Softimage.COM

Sent: Wednesday, January 25, 2006 8:23 AM

Subject: Re: "real" cameras in xsi

Holy thread revival batman!

I'm still a little confused by this stuff (I know I know). So in boujou, it wants the film back size (which I don't have, but I know it was shot on a Sony HDW-5900H), and the focal length which is 3'2". I tried searching on the web for the film back size of that camera but no information for that camera even comes up at all. So I guess my first real question is does anyone know the FB size of that camera? The only information that we have on the camera is the lens (7m which I'm assuming is a typo meant to be mm), the foc which is 3'2" and the PSF which is 23.98. Well and some other random info like height, tilt, Tstop, roll etc.

I ran a quick track on it without using the correct FB info and no surprise it comes into xsi with a FOV of something like 12 (way off visually). I'm a little confused with all this conversion stuff so any input would be appreciated.

Thanks guys

On 6/15/05, Robert Moodie <robertm(at)hybride.com> wrote:

While we're on the subject - here's a little something:

 

Run this (vbs) script:

 

NewScene

SelectObj "Camera_Root", "BRANCH"

ToggleVisibility

DeleteObj "Camera_Interest"

SelectObj "Camera"

Rotate , 0, 0, 0, siAbsolute, siPivot, siObj, siX, , , , , , , , 0

GetPrim "Null"

GetPrim "Null"

Translate , 0, 0, -20, siAbsolute, siPivot, siObj, siZ, , , , , , , , , , 0

 

Now, hide the grid in the camera view and in any other view - NOT THE CAMERA VIEW - select and rotate (pan) the camera.

Watch what happens to the nulls - there is no parallax.

 

Now run this:

 

SetValue "Camera.kine.local.pposz", 1.5

 

(What we are doing is offsetting the camera pivot to be 'behind' the lens - to see the pivots turn them on in Visibility options)

 

Now select and pan the camera as you did before and watch the magic of parallax.

 

This is no limitation of XSI - it happens in all 3D apps - but basicaly the pivot point of 3D cameras is also the Nodal point. And this never happens in real life.

 

For further explanation read this: http://360texas.com/tips/nodalpts.htm

 

Hopefully this may be a little help to someone. If you know the make and models of your 'real' cameras, tripods or dollies you can set the pivot offset values to match exactly what was on set.

 

_rob

 

 

 

 

 

--
-gc