Re: re: calculating exposure

Yeah, I understand that, but what about half stops?

Multiplying by half the square root of two doesn't work, because that's the
same as sqr(.5), and is the reverse of mulitplying by sqr(2).

John
----- Original Message -----
From: "Larry Fratkin" <Larry@MrPinhole.com>
To: <pinhole-discussion@pinhole.com>
Sent: Friday, December 29, 2006 5:06 PM
Subject: Re: [pinhole-discussion] 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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> >
> >
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Received on Fri Dec 29 21:23:47 2000