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usefeet · 02/11/08, 01:06 PM

>>>In practice, while that distance would theoretically be at the end of the universe, the distance is taken to be at 1000 x the focal length of the lens. So a 135mm lens should be tested at 135m (1m = 1000mm) while a 21mm lens is at practical infinity for objects at 21m.<<<

I'm in full agreement with this statement as the lens focussing did not change whether I focussed on the bright moon (that we have here in our clear conditions),
or the television mast in the distance. The mechanical disrepancy was about the same.

02/11/08, 01:06 PM	#26 (permalink)
usefeet Erfahrener Benutzer Join Date: 06/02/07 Location: Pasadena, Australia Posts: 154	Re: How Important is Infinity Focus? >>>In practice, while that distance would theoretically be at the end of the universe, the distance is taken to be at 1000 x the focal length of the lens. So a 135mm lens should be tested at 135m (1m = 1000mm) while a 21mm lens is at practical infinity for objects at 21m.<<< I'm in full agreement with this statement as the lens focussing did not change whether I focussed on the bright moon (that we have here in our clear conditions), or the television mast in the distance. The mechanical disrepancy was about the same.