Ayash Kanto Mukherjee wrote:
> You are absolutely right in your point. I know that quite well. The
> f-number is defined as the ratio of focal length to the diameter of the
> aperture (Am I correct?).
Yep - so the light-gathering of the bigger front element will
get "funneled down" to the same as the f4 when stopped down to f4
> But I am talking about the preliminary intensity of light reaching
> the film plane because of the wider diameter of the front element
> in the case of 50 mm f/1.4.
The intensity of the source doesn't enter into things. Unless
it differs between the time you use the f1.4 and the time you
use the f4, an autometering system will give the same shutter
speed at any given f-stop. Things do look brighter in the
viewfinder w/ the f1.4, but when stopped down this disappears.
Bill
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Bill D. Casselberry ; Photography on the Oregon Coast
http://www.orednet.org/~bcasselb
[EMAIL PROTECTED]
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