Archived posting to the Leica Users Group, 2000/08/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 6:01 PM -0400 8/8/00, Krechtz@aol.com wrote: >In a message dated 8/8/00 4:50:33 PM Eastern Daylight Time, >bdcolen@earthlink.net writes: > ><< TIME TO CHANGE THE SUBJECT - PERHAPS TO FLARE SUPPRESSION? > > >> >Okay! On a related matter, to what extent can use of contrastier or more >saturated color print or transparency emulsions compensate effectively for >lack of contrast in a lens, without introducing unwanted components or >defects? Similarly, in black & white, can conventional contrast enhancement >techniques such as pushing be utilized, without unduly limiting scale or >range? > >Joe Sobel It can't. The problem is that flare suppresses detail. It's similar to a lack of resolution. You can't ever get out more information than was there in the first place. Once your detail is obscured by flare, it's gone. You can use contrastier films, but they are the equivalent of sharpening techniques, whether USM or other techniques. For some purposes the results will be an improvement, but when you really get down to it, you haven't restored the original contrast, you've just created a version of new contrast that simulates the original contrast to an extent. Whether you find this useful or not is a different issue. Often it is quite useful. If you look at an MTF chart, you see that the graph is a report of the contrast at various frequencies, with the comparison being of the original (100%) against the result that the system being tested can reproduce. This is never 100%, but gets close with the best lenses, emulsions etc. What you are proposing is that we can shove the graph lines up closer to 100% by choice of emulsion. Unfortunately, each portion of the photographic system can only degrade what has gone before, ie, the lens cannot reproduce the scene at 100% contrast at all frequencies, and the film cannot reproduce what the lens sees absolutely perfectly (100% contrast transfer function result at all frequencies). We can get rid of some of the data, but we can't add data. * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com