There is an easy way to focus high powered lenses. Its called 'parallax' focussing and all you need do is move your head from side to side as you view the subject. When the image stops jumping, as you move, its in focus. A tree trunk or other sharp edge helps. Fine ground glass screens that are almost clear help too.
This method can be used with a stereo microscope or when doing macro work. The brain/eye is an amazing device and will bring something that is a little off into focus quite nicely. You need to stare into infinity - try to look past the subject at the sky. Don Dr E D F Williams http://personal.inet.fi/cool/don.williams Author's Web Site and Photo Gallery Updated: March 30, 2002 ----- Original Message ----- From: "Tom Reese" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, December 24, 2002 12:09 AM Subject: Re: Dumb Newbie Q - How do reflex lenses Work? > This site has a diagram that shows how it works: > > http://www.meade.com/support/telewrk.html > > Mirror lenses are also known as catadioptric lenses. > > I've gotten some very good pictures with my 1000mm f/11 mirror lens. > Focusing is tough especially toward dusk but I manage some decent pictures > even then. > > Tom Reese > >
