View Single Post
  #85  
Old 13-09-2009, 10:55 PM
dpastern (Dave Pastern)
PI cult member

dpastern is offline
 
Join Date: Jan 2009
Location: Brisbane
Posts: 2,874
Quote:
Originally Posted by Peter Ward View Post
With camera lenses the aperture can be varied with a constant FL.
So a 'wide open' a lens is operating at its maximim aperture. Not surprisingly it gives its brightest image at this point....hence the amount of flux coming down the pipe, so to speak, is soley (give or take) determined by the aperture. Does that help?
yes, that sort of makes sense to this lad. So, if I understand it all correctly, since the f stop on an astro setup is fixed and non changeable, then the amount of light coming through the aperture is fixed, only the exposure length and aperture width will affect the final exposure. Correct?

Dave
Reply With Quote