> Thanks Alain for that, I was able to fix the breaking of bars with the MIN
> bound!
>
> Can you help with the other doubt? All my scene parameters (for eg. distances of
> objs from camera, their thickness etc.) are in terms of focal length . How do I
> know the focal length of POVRay's camera, and set 'f' as a parameter and use it
> to define all other scene distances? And how to set camera aperture in terms of
> f-number?
>
>

I can't give you a definite answer, but, here's my interpretation :

The "f" parameter could be seen as the ratio between the length of the 
direction vector and the apperture value. It don't mather if that plane 
is in front or beheind the camera's location, just the absolute values 
count.

The focal length could be seen as the length of the direction vector.

The location of the camera is the optical center of the virtual lense. 
(as mentioned by clipca)

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> I can't give you a definite answer, but, here's my interpretation :
> The "f" parameter could be seen as the ratio between the length of the
> direction vector and the apperture value. It don't mather if that plane
> is in front or beheind the camera's location, just the absolute values
> count.
> The focal length could be seen as the length of the direction vector.

Thanks for that! I'll try it out and see if these work. Might need some
experimenting. Although I have to ask: why isn't there a definite answer to this
question? Is this something that POVRay doesn't want to simulate as such?
Because they (focal length, aperture) seem to be pretty standard things a person
would want to set in their scene setups when they place their camera, and be
able to easily control them to see changes/effects etc. in their outputs.

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Am 18.10.2016 um 06:42 schrieb udyank:

> Thanks for that! I'll try it out and see if these work. Might need some
> experimenting. Although I have to ask: why isn't there a definite answer to this
> question? Is this something that POVRay doesn't want to simulate as such?
> Because they (focal length, aperture) seem to be pretty standard things a person
> would want to set in their scene setups when they place their camera, and be
> able to easily control them to see changes/effects etc. in their outputs.

POV-Ray has its origins in the early world of computer graphics
enthusiasts, not the media world. That's why its camera syntax has been
strongly influenced by the inner workings of 3D rendering, rather than
camera technology.

The simple fact is that since then nobody has added an alternative, more
camera technology-oriented syntax -- yet.

The POV-Ray developers' tradition to favour extension by macros rather
than by hard-coded features probably plays a role in this as well.

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