Archived posting to the Leica Users Group, 2000/08/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Well, JD, the numbers make sense...but....Why do I keep thinking that being told you should want flare in a lens because it's a "good think" is a bit like being told that you want a dishwasher that leaks because then you can use the same water to wash the dishes and the kitchen floor? :-) B. D. > -----Original Message----- > From: owner-leica-users@mejac.palo-alto.ca.us > [mailto:owner-leica-users@mejac.palo-alto.ca.us]On Behalf Of John > Brownlow > Sent: Monday, August 07, 2000 4:16 PM > To: LUG > Subject: Re: [Leica] Shadow boxing > > > on 7/8/00 4:01 pm, Craig Roberts at croberts@zoomtel.com wrote: > > > "The flare helps to get to that threshold so it takes slightly > less image > > exposure to show up as density." - Ed > > > > > > Hmmmm. Thank you, Ed, but this sounds...almost > literally...like smoke and > > mirrors, or a sophisticated practical joke. I prefer not to > think about it > > any longer. My brain hurts. > > Oh, Craig, sit down, take some Advil and listen! > > Say it takes 5 units of light to 'activate' a film grain so it can be > developed. > > Let's say you're getting 4 units of light in through the > contrasty lens, so > the grain doesn't get developed. So no shadow detail there. > > In the flarey lens let's say you get 1 unit of flare all over the > film. Now > add that to the 4 units coming in as before, you get 5 units. > Ergo, you get > shadow detail. > > That's the theory and the number mean nothing and the reasons why it might > not work in practice are blindingly obvious even in this little thought > experiment, but the concept is pretty simple. > > -- > Johnny Deadman > > http://www.pinkheadedbug.com > > >