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Is Phototools FOV mislabeled? What does it do?


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I'm trying to reconcile the Phototool settings in Firestorm with what I know about digital photography.

So here's what I've figured out from pouring into the Second Life debug settings: Phototools View angle (Under DoF) is the same as the debug setting CameraAngle and FOV is the same at the debug setting CameraFieldofView.

View angle is measured in radian and FOV is measure in degrees. 1.047 is the default for View angle which equals 60 degrees, the default for FOV. Phototools even tells you you should adjust your FOV to match your View angle. It says "viewer" instead just to confuse you, I think. : )

If you move the slider for View angle, the camera will zoom in and out, increasing and decreasing the field of view. But adjusting the FOV settings in Phototools only brings your image in and out of focus.

According to wikipedia, FOV "is that part of the world that is visible through the camera at a particular position and orientation in space." That really seems to be what the View angle is doing. (I get the impression they might have mixed terminology, since people use Angle of view and Field of View interchangably.)

So is FOV as defined in Phototools, and probably in the debug settings, too, mislabeled? What exactly is the FS FOV setting doing?

Thanks. I know it's a really geeky and probably confusing question. I'll try to clarify anything that might not make sense.

 

 

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Thank you for the video. That first part about FoV was informative.

I did a little more digging on my own. As it says in the video, the FoV in Phototools refers to the vertical FoV. So that is mislabeled in Phototools, imo.

Here's why: You can describe FoV as either a diagonal or a horizontal and vertical measurement. Think of the FoV as a monitor - usually it's described as a diagonal measurement, but you can describe it just as easily as a horizontal and vertical measurement.

So this leaves the question of what is the Phototools View Angle? I'm guessing the View Angle is really the horizontal FoV, but I still not sure, since the View Angle can describe the FoV as a whole. So I'm still trying to reason through this a little.

You can see a little more about Angle of View in this wikipedia entry. I've also copied the image, below, showing what Angle of View does. The green area is the FoV described by the Angle of View.



So my remaining question, is what exactly is the  View Angle in Phototools? If I define the Angle of View, do I only need one FoV measurement - the Vertical one - to define my FoV?

If it helps, I've figured out Phototool View Angle is referring to CameraAngle in the debug wiki, which says, "Camera field of view angle (Radians)".

The Wikipedia entry on Angle of View indicates AoV and FoV are often used interchangably, so I think that's where some of the confusion is coming from.

 

   
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I have another update. :)

FOV is simply the View Angle, it seems. The View Angle is in radians and FOV is in degrees.

With rl lenses you only have a View Angle, however it seems necessary to set the FOV, too, in phototools. So maybe the View Angle is really the horizontal FOV and the FOV is, as stated in the debug settings, the vertical FOV.

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