camera match how

[pipjor]

i'm trying to camera match,

i have data in PS I'm trying to determine my FOV in 3ds camera

http://www.flickr.com/photos/40737650@N08/3814733086/

[Stephen Thomas]

Firstly what kind of camera are you using that gives you the option to select a spherical lens? Never seen that before.

 

You don't want a spherical lens anyway unless you're rendering a 360° panorama. Also you need to take the focal length multiplier for your particular camera into account. In your case it is 1.6216 so the 27mm focal length actually becomes 43.78mm for your max cam (35mm equivalent). This equates to a horizontal FOV of 44.7°.

Edited August 12, 2009 by stef.thomas
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[pipjor]

Firstly what kind of camera are you using that gives you the option to select a spherical lens? Never seen that before.

 

You don't want a spherical lens anyway unless you're rendering a 360° panorama. Also you need to take the focal length multiplier for your particular camera into account. In your case it is 1.6216 so the 27mm focal length actually becomes 43.78mm for your max cam (35mm equivalent). This equates to a horizontal FOV of 44.7°.

 

thanks Stephen,

I'm using Brazil 2(spherical lens)

 

how did you come up with 1.6216 as the multiplier???

[Stephen Thomas]

Ahhh, that explains it! You can get the focal length multipliers for most digital cameras here, I have it bookmarked: http://jalbum.net/forum/servlet/JiveServlet/download/16-23102-170830-5578/cameras.properties

[pipjor]

Ahhh, that explains it! You can get the focal length multipliers for most digital cameras here, I have it bookmarked: http://jalbum.net/forum/servlet/JiveServlet/download/16-23102-170830-5578/cameras.properties

 

Oh, so it seems kinda simple, the formula is(if i'm always using my Cannon Rebel)

 

Focal Length(PS data) x 1.6(Cannon Digital Rebel XT)= FOV(3DS Camera)

[Stephen Thomas]

Not quite. It gives you the lens equivalent as it would be on a full-frame sensor or 35mm film. The FOV is something else; as the lens value increases the FOV decreases i.e. a 28mm wide angle lens has a greater FOV than a telephoto 300mm lens. To get the FOV value you may have to create a standard max cam and input the lens value you calculated previously then copy the FOV to your Brazil camera.

[pipjor]

ah, if i were to use a "perspective" camera would my formula be correct then??

 

Focal Lenth(PS) x 1.6(Cannon XT) = 3ds Focal Lenth

[Stephen Thomas]

Yeah, that's it. So for example:

 

Camera focal length = 28mm

Max camera focal length = 44.8 (28x1.6)

Max camera Field of View = 43.78°

 

Camera focal length = 125mm

Max camera focal length = 200 (125x1.6)

Max camera Field of View = 10.286°

 

There is no direct way to calculate the FOV that I know of other than inputting the focal length into the max camera and noting the result.

[ronll]

I've found it's not that hard to do empirically and gives more accurate results. Set up your camera in your office and take a picture of a flat wall at a right angle. Measure how much wall you see and the distance from the wall to the image plane in the camera and do some trig.