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Re: [OM] Sunny 16?OT re. loony f/4

Subject: Re: [OM] Sunny 16?OT re. loony f/4
From: Richard Ross <rhdesign@xxxxxxxxxxxxx>
Date: Tue, 22 Jun 1999 10:05:51 +0100
At 21:20 21/06/99 -0700, you wrote:
>Now, there was a post about the loony f/4 rule, where exposure for subject
>lit by full moon is 1/ASA in days at f:4. So, for 400 speed film, exposure
>would be 1/400 of a day, or 86400secs/400, 216 seconds. If there is half a
>moon, would the exposure time be 432secs or is the relationship nonlinear?
>
>/Acer "cheeky whippersnapper" Victoria


I culled the Loony f/4 rule from a newsgroup a couple of years back -
here's the original posting:

>We've all heard of the "Sunny f/16 Rule": for sunlit subjects set your lens
>at f/16 and the shutter speed at 1/ASA of the film that your are using.
>For example if you are have Kodachrome 64 use f/16 and 1/60 of a second.
>Now for night landscape photography under a full moon we have:
>
>  "The Loony f/4 Rule": Set the aperture to f/4 and open the shutter for
>  1/ASA *days*.  That is, if you are shooting film at a speed of 100, at
>  aperture f/4, use a shutter speed of 1/100 day or around 15 minutes.
>  This is, of course, purely a starting point, and is based on the
>  illumination of the full moon.

I would guess that since half a moon gives you half the light, then you'd
need to open up one stop.

Cheers
Richard


Richard Ross
Hemel Hempstead, England
rhdesign@xxxxxxxxxxxxx


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