CGTalk - vray physical camera fov math?

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suki

05-19-2009, 01:20 PM

hi evereone,

does anyone know what's the math behind the relationship between the field of view
and the target distance / focus distance value in a vray physical camera.

with focal length and aperture at fixed values, the field of view gets wider the closer
the target distance gets.

oddly, this seem to happen in a logarithmic fashion flattening out towards longer distances

what i need is a field of view or focal length value that combines the "real" one with what
is produced by the target_distance.

any ideas what a formula for this could be?
I asked chaosgroup support but no answer so far

thanks,
chris

MarcoBrunetta

05-19-2009, 02:05 PM

Let's ask Wolfram!

http://www86.wolframalpha.com/input/?i=field+of+view

suki

05-20-2009, 12:15 AM

thanks for the link.
unfortunately it is more complicated than that :)

the vray camera mimics the behaviour of a real physical camera. this takes into account the
focus distance which i believe is a bit harder to calculate especially since there are numerous versions and derivates of the fornulas and i don't know how far the chaosgroup guys took it with their virtual counterpart

but in effect what i wnat would look like this:

i can assign a scripted controlller to the focal length value of the vraycam that would produce a modified focal length. when changing the focus distance, the focal length value would change but the rendered image would stay exactly the same

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