Re: Mountaineering and 3D-Photography

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Fri, 22 Aug 1997
>From: P3D  Lengel, Franz writes:
>.............
>Have clouds ever been considered as a natural enemy to 3D-photgraphy ?

*****  Anything moving is the enemy to single camera 3D! Clouds have ruined
more than one set of my pictures.

>...........
>2 cameras  +  2 persons  =  1 3D-photo
>
>The only solution to this problem seems to be, to do it in one shot. But
>what equipment does it need ?  Since some of the objects are kilometers
>away, and we want to see the shapes of the individual mountains, 2
>separated cameras are necessary, I assume. ........

******  This is the best approach. The simplest is for two persons to be
within sight of each other and wave before shooting. A mistake of a few
seconds usually doesn't ruin cloud shots. They move steady but slow. I've
gotten acceptable shots by shooting the first picture and moving quickly to
the other side of a clearing for the second shot.

>.................
>But how could one person handle both cameras ?  .........

If you aren't worried about Abominable snowmen running off with your camera
gear, use tripods for the cameras and remote control devices for the shutter
of one camera. Or a timing device hooked up to trigger the shutter. A bit of
experimentation will get you coordinated with such a device to within close
enough tolerance (if you know what spots you are going to shoot from).

>........... But how to ensure
>the right alignment of the 2 cameras regarding the remaining axes to
>ensure that both are directing to the same objects. 

******  Pick out your target thorougly with an eye to readily identifiable
features. Things to make sure of are: 

<<< make sure that both taking positions are level relative to each other, 
<<< Make sure the lenses are set the same,
<<< note the position of the horizon relative to the viewfinder frame, 
<<< identify the point of infinity in your scene.

Since you are using a very wide stereo base and the object of your image is
the distant mountains, you cannot reliably use them as the infinity point.
In theory the infinity point is that point that stays in the same relative
position in both shots due to it's distance. However if the first shot is
the left shot, I frequently will deliberately point the camera in the second
shot, slightly to the right side of the same infinity point of the first
shot. Too much and you end up with distortions, but a small amount seems to
help. This is the equivalent to using an infinity point beyond the
mountains, though often such points are not visible. However, a rising moon
might serve perfectly!!!

You might consider using compasses to make sure of the pointing direction
for the two person shots. If you can see each other (best) then simply
arranging for one person to wave just before taking the shot should work for
most circumstances. Distant clouds move but usually not so fast that a few
seconds will screw things up.

Other methods to consider might be small walkie talkies for communication
and coordination, or even radio controlled devices hooked up to the shutter
controls. Garage door openers might work but they don't have a huge range by
themselves. You might get an electronic technician to hook up a small linear
RF amp to an ordinary garage opener and it will dramatically extend the
range. I have a friend who tried it once and was able to get a 10 mile range
out of it!!! We never tried to figure out how many garages across town might
have opened during his test. That wouldn't be a problem on a mountain top
though. You will need a receiving device with some means of triggering the
shutters too.

.................. Has anyone experience in using a walking-stick 
>as 3D equipment ?  .............

<<<<<<<  I'd use the walking stick to get up there and set it down out of
the way to use the cameras. They might work as a monopod on occasion but it
would be hard to use them for precision situations. Keep them handy to
frighten off Yeti...

Hope you get some great mountain shots!

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


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