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

[Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 11:24 AM -0800 11/21/97, John Bercovitz wrote:
>Peter Davis writes:
>
>> One partial work-around is to "overlap" the bodies, kind of like this:
>>
[deleted]
>>
>> 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?
>
>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

Another way to say it is that the fields of view are only the same at that
one distance.  Imagine drawing two diverging lines in front of each lens
representing the left & right boundaries of the field of view.  These lines
will diverge more quickly for the shorter lens, and the two sets of lines
will only intersect at one distance...

-Jim C.



----------------------
Jim Crowell
Caltech Division of Biology
216-76
Pasadena, CA 91125
Tel: (818) 395-8337
Fax: (818) 795-2397
jim@xxxxxxxxxxxxxxx



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