Archived posting to the Leica Users Group, 2001/02/06

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Subject: [Leica] Seeing Red
From: Mark Rabiner <mark@rabiner.cncoffice.com>
Date: Tue, 06 Feb 2001 18:48:25 -0800
References: <003001c09094$b6f912b0$617079c0@drt4>

Before i ran my tank of film today i did a quick test on the second half of my
roll of Delta 100
http://www.schneideroptics.com/filters/list/7/ir2.html

check out the chart above

I set up a tripod and fired off a few; metering through the lens with 091 filter;
this is a "3 stop" red filter.
My deck with some sky in my backyard.
Came out right on the money like I'd expect to see.

Then i put my radical red 092 filter on:
"B+W 092 [Wratten 89B] [Schott RG 695]
This dark-red filter is for black and white infrared films and filters out light
below, approximately, 650 nm. It allows pictures of a pure red image while
making good use of the relatively low sensitivity of infrared films. Filter
factor is approx. 20 - 40."

This filter is so red it looks black from a few feet off.
When you hold it up to the sun the disk is red. That's it.

Exposing though the lens.
I was getting readings like an 8th of a second at f11. It was 2 o clock and
mostly cloudy.
I was assuming the extreme red filter would cut through to the barely
perceptible blue you could just make out through the thick clouds.

Ran the 10 rolls. They are dripping now.

Guess what?

when i put that second filter on, the 092 the film came out 100% totally
BLANK
NOTHING
NADA
NOHOW!!!

So i guess the meter on the Leica is a lot more sensitive to 660 and over than
Delta 100 is!
next time i meter without the filter i guess!
And I THOUGH THIS WOULD BE EASIER THAN INFRARED!!!


mark rabiner

In reply to: Message from "Austin Franklin" <austin@darkroom.com> (RE: [Leica] how can the 75 Lux focus go bad?)