Real World Equivalent Focal Lengths

[msoon2k]

Hi guys,

Is there a way you guys achieve real world equivalent focal lengths using Octane?

In other 3D apps, there is usually a focal length measurement available, but with Octane it's just a floating point number scale.

I'm wondering because I do a lot of photography footage compositing. Any feedback is much appreciated! Thanks.

[face_off]

My (potentially wrong) understanding is....

There is "Focal Length" - which is the camera term for how quick things get out of focus - and you use the Octane Aperture (size) for this, and potentially the Octane Field of View and backplane size ratio (ie. the ratio of the render resolution X to Y). You'll need to google for a formula to convert between Focal Length and Aperture. I think other 3d apps generally use FStop for this.

There is "Focus Distance" - which is the Octane field I think you are using, and it is the distance (in metre?) from the camera to the focus point.

Paul

[msoon2k]

Hi Paul,

Thanks for your response.

Basically I need to render shots that fit the same FOV as my real world camera lens.

So say if I shot a plate at 35mm FOV, I need to get Octane's camera to the exact same FOV for things to look "matched".

I don't think this has anything to do with aperture itself. It's just the zoom of the lens - so to speak.

[face_off]

Octane's FOV is horizontal - so the formula is:

Octane fov = 2.0 * atan ( ( FilmbackWidth / 2.0 ) / focalLen) * 180.0 / pi

But if you have take portrait shots - you might need to tweak that.

Paul

[msoon2k]

Thanks Paul.

Any chance of incorporating a tool that would do that for us inside of octane?

[face_off]

Any chance of incorporating a tool that would do that for us inside of octane?

It should be very easy to do with some LUA script. May I suggest posting this as a "script request" in the LUA forum http://render.otoy.com/forum/viewforum.php?f=73.

Paul