Re: PHOTO-3D digest 1327

[P3D <CJMCE@xxxxxxxxxxxxxxxx>]

The most common filter for aerial mapping cameras is a "minus blue" (yellow).
It's so common, color films are specially formulated to render the desired
color balance only when used with a yellow filter.

I recall being told that the fanciest lenses (once classified in the '70s)
had specially-tinted glass that was already deep yellow & orange to enhance
their ability to "cut through high-altitude haze WITHOUT a filter".  I now
suspect that the GEOCON IV lens was made up of these rare earth elements...

I understand that these lenses are now occasionally sold on the surplus market.

Clifford J. Mugnier  (cjmce@xxxxxxx)
Topographic Engineering Laboratory
Department of Civil & Environmental Engineering
University of New Orleans
New Orleans, Louisiana  70148
Voice: (504) 286-7095
FAX:         286-5586


------------------------------