Re: Aerial hyperstereos

[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

Dr. George A. Themelis writes

>Going to Greece we usually take SAS and stop in Copenhagen (lovely city!)
>Getting a seat selection is not always possible so I have my fingers
>crossed.

Next time try going with SwissAir if they fly to your town. The route
over the alps is amazing. In general I found the route that they take
to be the most scenic from all the different routes. With SwissAir the
route takes you from Athens west to Zurich and passes Patras and along
the whole east coast of Italy and then finally the Alps. On the second
leg of the flight it flys over Paris. Regretfully I didn't have my camera
at the time.

Paul Talbot writes

>I tried to be a little quicker on shots from lower altitude.  I think
>this would also depend on the focal length of the lens.  (I looked at
>the formula posted recently, but haven't "learned" it yet!)  My 28-85
>is broken, so I only had my 70-210 to work with.  There is also a
>discussion of timing for aerial hypers in the FAQ, I think.  I read
>it after all my trips, though!

You have a point that on the lower altitude shots they should be taken
quicker but the focal length shouldn't be a concern regarding the stereo
base. The focal length won't change the perspective of the view. Only the
actual distance from the camera to the object accomplishes this. A simple
experiment to try is, take your camera and point it to a tree in the 
middle foreground. Now move the camera closer to the tree and you'll
notice that the tree obstructs the background more and more. Now go back
to the original position but this time zoom in to the tree until the
magnification of the tree is the same as when you moved into it. What 
you'll notice is that the tree hasn't obstructed the background at all
at any of the progressively increasing focal lengths. The effect of zooming
in on the image is that it has the same persepective regardless of the
focal length but the result is that you have cropped the tree to fill the
whole image. 

Finally all this talk of aerials reminds me of a picture a good friend of
mine had send me from space. This was posted awhile back ago and I am not
sure if it would fit the definition of of aerial 3d photography.
http://www.generation.net/~jacob/alien.jpg
Here is another one that I have posted before, that would fit the definition.
http://generation.net/~jacob/myhouse.jpg

Gabriel                                              <---what no comments?!
 


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