Archived posting to the Leica Users Group, 2000/08/08

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] Performers and flare
From: Mikiro <arbos@silva.net>
Date: Tue, 08 Aug 2000 14:58:32 +0200

on 8/8/00 10:53 AM, Erwin Puts at imxputs@knoware.nl wrote:

snip
> The flare issue. Flare is defined as unwanted stray light, that will be
> uniformly distributed over the whole image area. If we have a scene from
> black to white, we will have a range of figures that indicate relative
> contrast, we have a rnage of 100 to 0.25 lux, indicating light and dark
> areas, which is a contrast of 400:1. Add a uniform flare level of 0.25 lux
> and we now have 100.25 and 0.5, giving a contrast of 200:1. The effect on
> the dark areas is big and on the lighter areas to be neglected. This example
> shows two things: flare does simply give greater negative density in the
> thin parts of the negative (the black areas), and will give a dark grey
> instead of a black, suggesting detail, which is not there.
> The old story that you can use a low contrast and/or flare prone lens to
> compensate for high contrast in the scene is not correct. The highlights are
> not affected and the dark areas just become muddy.
> The best proposal: buy a high contrast lens, use a 100ISO BW film that gives
> good toe density and expose and develop to get the maximum contrast your
> print paper can handle.
> 
> 
> Erwin

Thank you for the input, Erwin.

We often hear that some lenses are not "too" contrasty and thus good at
rendering shadow details.  Such lenses supposedly take advantage of
100.25:0.5 in place of 100:0.25 in limited tonal ranges of film/paper. My
understanding is: the higher the contrast, the better...  Then, how can we
make the best of high contrast capability of a lens with film/paper? Does it
work just to compress the range to a narrower one (with low contrast
film/paper)?  TIA for further input.

MIKIRO
http://arbos.silva.net