Re: Sigma F/1.4 lens?

Alan Browne <alan.browne@xxxxxxxxxxxxxxxxxxxxx> wrote:
Alan Browne wrote:
Floyd L. Davidson wrote:

frederick <lost@xxxxxxx> wrote:

Alan Browne wrote:

Floyd L. Davidson wrote:


It won't be any brighter than an f/1.8 or f/2.0 lense,
and might not (depending on the camera) be much
different than an f/2.8.


Of course it will be brighter and that will be
noticable in lower light conditions. It won't be very
perceptible in high light conditions as the viewers
iris will stop down.


It might not be.



True, but not for the reasons you state.


Some dslrs default to an f-stop "at rest" of f2.8 - with



I've never seen a camera body that does that. (As opposed
to the fact that all SLR cameras necessarily have a maximum
aperture through the viewfinder which is different than the
optical path to the "film plane".)
Regardless of the size of that aperture, the amount of
light presented to it by a faster lens is more than
with a slower lens and hence more light will get
through.

... by unit area...

It's not.

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@xxxxxxxxxx
.

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