Archived posting to the Leica Users Group, 2001/10/15

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

Subject: Re: RE: [Leica] Clear Plastic Tape (now Camera destruction)
From: Walter S Delesandri <walt@jove.acs.unt.edu>
Date: Mon, 15 Oct 2001 13:25:10 -0500 (Central Daylight Time)

On Mon, 15 Oct 2001 11:54:00 -0400 Austin Franklin 
<darkroom@ix.netcom.com> wrote:
> > So far I've been UV-filter-less for a year.....
> >
> > Walt
> 
> Out of curiosity, did you notice your images were any better without the UV
> filter?
> 
> --Nah, but my use of the lenses is not as critical as say Erwin's...
I shoot Tri-x or CN400 (various brands at EI250 or so)-HANDHELD- and print only 
8x12.....there's NO way I could tell a difference in sharpness....
as for flare, without a strict A/B comparison, any conclusion would 
be anecdotal...
As a note, when I was in college (photojournalism) we had a photo-physics 
class...I chose to "test" lenses for a project....I recall testing my 
then "beater" 50 f2 chrome, with some cleaning marks, dust inside, AND
accidentally left a tiffen UV on it....now bear in mind that this was a 
"no-flare" setting, but still, the resolution exceeded our test charts at 
the distance we used!!! (I believe 125 lpm was the finest gradation on the 
chart, at the prescribed distance)....we used a Leitz (!!!) microscope at 
fairly low magnification (perhaps 50x?--it's been 20 years!).....to look at 
the resulting negatives-- 
Tech Pan (perhaps High Contrast Copy in those days)-I believe.
The "on film" resolution is expressed as 1/total resolution= 1/max film resolution+
1/max lens resolution.
At least that's what I recall--hope it's correct!

Point is, the lens resolution, with or without a filter, is only one part of the 
equation.  If your camera is handheld at less than 1/focal length, there's NO WAY
anything else matters....might as well be an Argus C-3.  Most of my favorite photos, 
however, were shot under these conditions! (pushed tri-x, handheld, wide open @
1/15 sec, braced on a chair or pole or whatever!!)

As for increased flare, bear in mind that in the early days of coated lenses, then-active 
photojournalists thought that the UNCOATED lenses were better for available light!...
the flare level "filled in" the shadows (pre-exposure, anyone?)...truly a case of 
practice NOT following science!...

To each his own!....I might, however, still make fun of ya'll if you post something 
really dumb.
:) :) ;)
Walt





- --
To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html