Archived posting to the Leica Users Group, 2002/06/10

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Subject: [Leica] Re: 135 Apo Telyt-M flare and spots on images
From: Jim Brick <jim@brick.org>
Date: Mon, 10 Jun 2002 08:45:35 -0700

At 11:54 PM 6/9/2002 +0100, Simon Lamb wrote:
>I just developed a roll of Delta 100 that I shot using my new (used) 135 Apo
>Telyt-M.  I noticed two anomalies in the negs that I scanned which I hope
>someone here might be able to explain.  The images are entirely
>uninteresting as I just wanted to see what the lens could do.
>...



This looks to me like a reflection from inside the lens barrel/camera body, 
that it, a shiny spot (it doesn't have to be bright metal, it can be shiny 
black) somewhere inside the lens/camera that, when light hits it, reflects 
as secondary unfocused light causing a reduced contrast in an area of the 
image or a bright spot, depending upon the subject being photographed AND 
how the lens is focused.

I've seen this before, albeit not with a Leica lens/camera.

Sometimes, this can be caused by a reflection from inside the camera body. 
And will show up only with certain lenses because different focal lengths 
have their rear element at different distances from the film plane. A 135mm 
lens will have its lens elements much farther away from the camera 
body/lens mounting flange than shorter lenses, Depending upon the subject 
being photographed, a bright spot in the camera body, inside the mounting 
flange, inside the rear 135mm lens barrel, or even within the lens itself.

Take the lens off of your camera, take off the back door, put the camera on 
bulb and hold down the release, then shine a penlight around, pointed into 
the camera from the front, and from the rear look for reflections.

Do the same with the lens. Look from the rear while shining a penlight in 
from the front.

Jim

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