P3D Re: Re: A stupid (?) twin camera idea

[bercov@xxxxxxxxxxx (John Bercovitz)]

Peter Davis writes:

> One partial work-around is to "overlap" the bodies, kind of like this:
> 
>         +--+
>         |  |
>      +--+  +--+
>      |        |+--+
>      +--------+|  |
>             +--+  +--+
>             |        |
>             +--------+
> 
> The problem here, of course, is that one lens is now farther back 
> than the other.  So, here's my stupid idea ... is it possible to 
> put different focal length lenses on the cameras to give them,
> effectively, the same field of view?  For example, could one put a
> 35mm lens on the rear camera, and a 28mm on the foreward one?  Or 35
> and 50?

This has been done but best is to leave the lenses the same focal
length.  Since the difference in distance to the objects is small,
there is little effect.  It's not only the angle of view which is
important, also the size of the images is important.  With different
focal length lenses, the sizes of more distant objects will be different.
This is one way to look at it, anyway.  Another way would be to say that
you are suggesting a change in magnification to compensate for a change
in perspective.  This only works if you are taking pictures of objects
which lie at a single distance from the cameras.

John B


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