Sir graywolf,
American Heritage Dictionary - Cite This Source ap·er·ture
(ap'?r-ch?r) Pronunciation Key
n.
1. An opening, such as a hole, gap, or slit.
2.
a. A usually adjustable opening in an optical instrument, such
as a camera or telescope, that limits the amount of light
passing through a lens or onto a mirror.
b. The diameter of such an opening, often expressed as an
f-number.
c. The diameter of the objective of a telescope.
So, aperture is often expressed as an f-number. I find this to be
univeraslly true when conversing with other photography. Example: Hey Bob,
"What aperture are you using?" I answer, "Eight, Fred." Fred knows I am
giving giving him Normalized aperture. An f-stop is simply a normalized
aperture - normalized to the focal length. It's the same concept as
normalized pressure. When the sidewall of my tire says "MAXIMUM PRESSURE: 45
PSI", I don't add about 15 psi to account for atmospheric pressure. We all
know that the pressure given in normalized to atmospheric pressure.
If you wish to anal about it and still be "technically correct" , I suppose
you could refer to the f-number as thr "specific aperture". At least other
photographers will get some useful information from you when you're asked
for the aperature you're using.
When someone asks the time, they don't want to know how to make a watch.
Take my word for it.
----- Original Message -----
From: <[EMAIL PROTECTED]>
> In a message dated 4/29/2007 7:36:03 A.M. Pacific Daylight Time,
> [EMAIL PROTECTED] writes:
> ----- Original Message -----
> From: "graywolf"
> Subject: Re: M85mm f2.0 bokeh
>
>
>> Most folks do confuse f-stop with aperture, I sure used to. However,
>> they are not the same thing. So you are mistaken here (I have not looked
>> at the Wikipedia article to see if it is correct or not).
>>
>> I am not going to go through all this again, folks, look in the
>> archives; or better yet, get the formulas and calculate DOF using f-stop
>> and aperture diameter, go out and shot some photos and compare them with
>> your calculations. Then, like me, you will never make that mistake
>> again.
>
> =========
> Huh. Haven't been paying much attention to this thread.
>
> But I would presume while the diameter of an aperture opening could be
> set
> the same from lens to lens if one fiddled around, a f stop is dependent
> on the
> focal length of the lens. So a f/8 on a 16mm and a f/8 on a 200mm say,
> would
> actually have a different size of aperture opening if one measured the
> diameter.
>
> Is that what you are talking about?
>
> Thanks.
>
> Marnie aka Doe :-)
>
>
>
>
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