From: RichA on
On Aug 20, 1:15 pm, "Thomas T. Veldhouse" <veld...(a)yahoo.com> wrote:
> RichA <rander3...(a)gmail.com> wrote:
> > On Aug 20, 3:40 am, "Pete D" <n...(a)email.com> wrote:
> >> What about ISO 50?
>
> > There is always neutral density filters.
>
> There is absolutely no point in that barring one case only, and that is the
> case where you want a lower ISO solely for the desire to use longer shutter
> speeds. The whole idea is to let all the photons hit the sensor and be
> counted ... minimal noise. Modern sensors are so low noise at ISO100 anyway,
> it may not be a practical difference, but in theory, it would be better to
> have true ISO50 than to reduce the light via a neutral density filter [which
> also is a cumulative drop in quality due to more glass].
>

An ND filter is just one option. Adjusting f-ratio is another to
extend shutter speed.
In point of fact, some cameras that can do 50 ISO show as much or even
more noise at that setting as 100. There is no measurable drop in
quality using a good quality filter, unless you catch a reflection or
there is some unforseen interaction between a filter and lens combo,
more likely with very wide angle lenses. But then using 50 ISO would
be easier than using any filter.

From: DoN. Nichols on
According to Thomas T. Veldhouse <veldy71(a)yahoo.com>:
> RichA <rander3127(a)gmail.com> wrote:
> > On Aug 20, 3:40 am, "Pete D" <n...(a)email.com> wrote:
> >> What about ISO 50?
> >>
> >
> > There is always neutral density filters.
> >
>
> There is absolutely no point in that barring one case only, and that is the
> case where you want a lower ISO solely for the desire to use longer shutter
> speeds.

Actually -- I have one example where neutral density filters
would work, and the camera (my D70) won't go to a low enough ISO to
*allow* a properly exposed image. This is with the older version of the
Medical Nikkor (200mm f:4 with close-up lenses and built-in ring flash).
The closest shots, with the standard AC-powered flash power pack have
too much light for anything above 25 ASA (this is an *old* lens --
before they started calling the same system ISO). The slightly newer
version with a flash power pack powered by twelve D cells, has a switch
on the panel to drop the effective flash output by a factor of 4, so I
can use that one with the minimum ISO 200 on the D70 without a neutral
density filter.

Of course -- the *ideal* neutral density filter for this would
be one which fit *around* the actual lens, and dropped light from the
flash ring instead, so the stack of "filters" (up to two close-up lenses
expected in the design) would not be so extreme. And with the closest
shots, the neutral density filter would have to be closer to the lens,
because that close-up lens (the 2X from the set) has too much curvature
to allow filter threads on the outboard end.

> The whole idea is to let all the photons hit the sensor and be
> counted ... minimal noise. Modern sensors are so low noise at ISO100 anyway,
> it may not be a practical difference, but in theory, it would be better to
> have true ISO50 than to reduce the light via a neutral density filter [which
> also is a cumulative drop in quality due to more glass].

Well ... there is the risk of overflowing the charge buckets
with that much light, so there would be a lot of blown pixels.

Enjoy,
DoN.

--
Email: <dnichols(a)d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
From: Thomas T. Veldhouse on
RichA <rander3127(a)gmail.com> wrote:
> All depends on the task. I just read an article by a sports photog
> who said he has no choice but to shoot a 3200 ISO f2.8 at many indoor
> venues because of the lighting.
>

I very very rarely shoot above ISO400. In fact, I rarely shoot higher than
ISO100.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

From: Thomas T. Veldhouse on
Rita Berkowitz <ritaberk2O04 @aol.com> wrote:
>
> You're the perfect candidate for the Mk III and six Nikkor to EOS adapter
> rings. The old Mk III has been hovering in the ISO 800-1600 range since I
> got it.
>

I think the Nikon D3 is right up there above the Mk III as it will use the
Nikkor lenses natively and is probably cheaper than the Canon body.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

From: crownfield on
In article <3yByi.1078$vq6.185(a)textfe.usenetserver.com>, veldy71
@yahoo.com says...
-RichA <rander3127(a)gmail.com> wrote:
-> All depends on the task. I just read an article by a sports photog
-> who said he has no choice but to shoot a 3200 ISO f2.8 at many indoor
-> venues because of the lighting.
->
-
-I very very rarely shoot above ISO400. In fact, I rarely shoot higher than
-ISO100.

in a studio with strobes, right. available light is different.

so you are unlikely to shoot moving children in dimmer light.

either less than bright light
or fast action are not of interest to you.

-
-