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Re: [OM] pinhole OM

Subject: Re: [OM] pinhole OM
From: WKato@xxxxxxx
Date: Thu, 28 Oct 1999 10:14:24 EDT
In a message dated 99-10-27 20:41:28 EDT, you write:

> OK folks, I have a special pinhole for my OM-2n. It's made from a body cap,
>  where the center was drilled out and a pinhole plate was glued in place. It
>  is supposedly 50mm f/185. Obviously, there is no aperture connector to the
>  body or meter in the camera. So, I tried setting the film speed to 400, the
>  switch to auto, and cocked the shutter and released it. The shutter opened,
>  stayed open for about a minute, then closed. Was this an acurate exposure?

1 minute at f/185 is the same as f/2 at 1/8 second so this is theoretically 
within the metering limits of the camera.  But for the camera to read this 
correctly the aperture information lever has to be pushed in the full open or 
clockwise position as to look at the camera. If you look at a simple T mount, 
the aperture pin is in a fixed position indicating full open. So if this pin 
isn't pushed full clockwise the camera thinks you're stopped down to f/45 or 
something adding time onto the exposure to compensate.

Using the sunny 16 rule of f/16 @ 1/400 (assuming you were outdors), would 
yield f/185 at 1/25 so something is amiss and you're horribly overexposed.

Warren

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