CH,
At 3:30 AM +0200 5/30/04, Listar wrote:
>From: "C.H.Ling" <chling@xxxxxxxxxxxxx>
>Subject: [OM] Re: Dynamic range of films (and digits)
>Date: Sat, 29 May 2004 19:37:30 +0800
>
>
>Joe, I believe you are still using film and have not played with
>some good DCs yet.
Right about that, so far. Someday I'll get a digital camera, but
probably not until I need one (versus lust after one). And, digital
cameras get better by the day, so I'm biding my time.
>A good DC can keep very good control of shadows, even the E-10
>can allow for two stops under and pull up in software later (with the
>increasing of noise) with minimum loss of shadow details.
If it has the necessary dynamic range for the scene. It's still
expensive to make a camera with both a large dynamic range and
high-resolution rendering of subtle tonal differences, all with low
noise, but this will cease to be a problem in a few years, with the
march of progress.
>Here is an example of a E-1 shot with 11-22mm I took today, the foreground
>buildings was under at least 1.5 stops, try to download and play with it
>under you photo editing software you will know how good the shadow is. BTW,
>it was shot under JPEG mode, if you shot RAW it will be even better!
>
>http://www.accura.com.hk/exp_test.jpg (~300KB)
It comes out very dark on my computer, and appears to have been taken
on an overcast day, which tends to compress the brightness scale.
For comparison, do you have a picture of a brightly-lit noontime
scene with burning highlights and deep shadows? I imagine the E-1
does better at this than the E-10, but you probably have the pictures
to tell.
I did magnify it until the pixels were each 3x3mm on the screen.
Olympus has very good in-camera software. The pixellated edges are
very smooth, with minimal color artifacts.
Also, I have some film data on dynamic range. The toe and shoulder
of the curves is included. The linear range is about one log unit
less on input. If the curves differed by color, the green curve was
used.
Tri-X Pan (ASA 400, D-76 developer, 11 minutes): The input range is
-2.6 to 0.0 Log10(lux-seconds), a dynamic range of 398.1:1, call it
400:1 (8.6 stops). The output (log10 density) range is 0.3 (base
fog) to 2.1, a range of 125.68:1, call it 126:1 (7 stops). The
contrast index is in the range 0.5 to 0.6. With slow development in
T-Max developer, the output range can match the input range (contrast
index is 1.0).
Kodachrome25 (reversal film): Input -1.5 to +0.5 Log10(lux-seconds),
a 100:1 range (6.6 stops). Out 3.5 to 0.3, a 1586:1 range (10.6
stops). K25 increases the contrast a lot: contrast index is high.
Provia 100 (reversal film): In -2.5 to 0.0, a 316:1 range (8.3
stops). Out 3.6 to 0.1, a 3162:1 range (11.6 stops). High contrast
index.
Astia 100 (reversal film): The datasheet exposure curve has a
problem, preventing reading the values.
NPS 160 (negative film): In -2.5 to +0.5, for a range of 1000:1 (10
stops). Out 0.6 to 2.2, for a range of 40:1 (5.3 stops).
Film has definitely gotten better over the years.
Joe Gwinn
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