Re: My cloud story...

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Sat, 23 Aug 1997 00:25:39 -0500
>From: P3D Larry Berlin  <lberlin@xxxxxxxxx>
>Subject: Re: My cloud story...

>>>Paul Talbot writes:
>>>A potential problem I see with this is that clouds generally don't
>>>just move, they change shape at the same time.  That suggests to
>>>me that significant retinal rivalry will usually result...

><<<<<<  This will vary according to where the clouds are and what type they
>are. I shot several hyperstereos of sunset clouds along the trip to NSA.
>They were very distant, almost to the horizon. All were high altitude types
>that weren't very turbulent. At that distance, it takes quite a bit of
>change for the difference to be noticeable. My recent cloud images sound
>similar to the ones Dr. T described. Closer clouds or clouds of the puffy
>type are a different story...

Clouds with hazy, indistinct surfaces generally don't show much depth
when you try to photograph them in 3D, but they're also less likely to
spoil a 3D shot of something else. As for the fluffy cumulus clouds with
sharp surfaces, I believe they are formed largely as a result of turbulence,
so while they make great 3D subjects, the synchronization of the shots is
usually important to getting a good 3D result. One method I've used when
the two cameras are close enough for voice communication between the two
operators is to use a countdown, such as "one, two, three, GO!" - that
usually gets the two shots within half a second of each other.

Near sunset, the forces that create the turbulence often go away, while
the cumulus clouds may persist for some time, and may even drift along
in a steady, non-turbulent wind. This can make it easier to get a
good 3D shot - sometimes even with consecutive shots from the same
location if the wind direction is perpendicular to the line of sight.

John R


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