Re: re: calculating exposure

John,
 F stops are based on the square root of 2. For the non-math inclined you
just start with 2.8 and 5.6 and alternately double each:
 5.6 11 22 45(44) 90
        8 16 32 64

Larry

-----Original Message-----
From: John Yeo <jonnieo@thegrid.net>
To: pinhole-discussion@pinhole.com <pinhole-discussion@pinhole.com>
Date: Friday, December 29, 2000 4:16 PM
Subject: Re: [pinhole-discussion] re: calculating exposure

>I didn't see it there. Where on the page is it?
>
>How does one calculate half stops? I tried adding 1/22 and 1/32, then
>dividing by 2, but i got f/26.07, not 1/27.25 like you got. I would like
to
>make a dial calculator with half stops because most of my cameras have
>apertures that are not full stops. I've finally given in to using a
>spotmeter after many failed pictures :P I was chewed out last year for
>criticizing people about being so concerned with the exposure. I guess I
>deserved it.
>
>John
>
>John----- Original Message -----
>From: "Andrew Sias" <andrewsias@excite.com>
>To: <pinhole-discussion@pinhole.com>
>Sent: Thursday, December 28, 2000 5:04 PM
>Subject: Re: [pinhole-discussion] re: calculating exposure
>
>
>>
>> > It's easy to make a dial calculator like the one on an exposure meter,
>> but
>> > that goes to longer exposures and slower film speeds. I've got one on
>> > my web page at http://linux.bbn.com/~koolish
>>
>> Thanks for the dial calculator. I downloaded it and am going to make
one.
>> I have been using something similar but it is a bit more cumbersome. I
>made
>> a long slide-rule with all of the f-stops and speeds projected beyond my
>> handheld light meter. The only information my slide rule has that the
>dial
>> doesn't have is that I have included f-stops and shutter speeds halfway
>> between each of the standard settings. For example: the extra f-stop
>> between f/22 and f/32 would be f/27.25. I have done this all the way up
>to
>> f/4096 and 16,384 seconds (or 4.5 hours). Most people don't need to go
>that
>> high but you never know.
>> Andrew
>>
>>
>>
>>
>>
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>
>
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Received on Fri Dec 29 20:09:20 2000