RE: light gathering vs diameter of reflecting spheres

[Nathan Myhrvold <nathanm@xxxxxxxxxxxxx>]

Weather reseacher use "whole sky cameras" to record cloud cover.  These are
basically an ordinary camera lens pointed at a mirrored sphere - those I
have seen are approx 8-12 inches in diameter.  The camera appears in the
picture, of course, and the view is quite distorted.

Nathan

> -----Original Message-----
> From: Charles Stumpfel [mailto:stumpfel@xxxxxxxxxxxx]
> Sent: Thursday, July 06, 2000 8:13 AM
> To: Panorama-l@xxxxxxxxxxxxxxxxx
> Subject: light gathering vs diameter of reflecting spheres
> 
> 
> Knowing next to nothing ---
> 
> I'd like to understand the how reflectors might be used for panoramic
> imaging.
> 
> A video camera was set up viewing a  3/4" diameter chrome steel ball
> bearing so that the ball's image filled the camera's vertical FOV.
> 
> How does the diameter of a reflecting sphere affects light 
> gathering?  In
> other words does a larger diameter ball bearing,  imaged to 
> still fill the
> FOV, cause more light to fall in the image?   I'm ordering a 
> 1" diameter
> ball to find out the quick way.  [The 1 " diameter ball is supplied by
> Small Parts, Inc. in Miami FL]
> 
> Does anyone know of a supplier for precision ball bearings 
> larger than 1"
> in diameter?   Any specifics on other commercially available curved
> reflectors other than ball bearings would also be of interest.
> 
> 
> Chas Stumpfel
> 
> 
> 
> 
>