At 3:28 AM +0200 6/1/04, Listar wrote:
>From: "C.H.Ling" <chling@xxxxxxxxxxxxx>
>Subject: [OM] Re: Dynamic range of films (and digits)
>Date: Tue, 1 Jun 2004 00:19:39 +0800
>
>
>----- Original Message -----
>From: "Joe Gwinn" <joegwinn@xxxxxxxxxxx>
>
>> 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.
>
>Even being a die hard Olympus fan, I have to say 10D is at least two stops
>better than E-1, at ISO100 the noise is not noticable even if you
>underexpose by two
>stops and later pull it up; still very low noise at ISO400 and under
>one stop. The
>problem is the 10D color does not look as good as the E-1 even with the
>excellent C1 RAW convertor.
Isn't 10D one of those C*n*n thingeys? Wash your mouth out with soap!
So the E-1 has worse noise and yet the pictures look better, likely
due to better color fidelity. Hmm. The megapixel ratings of the two
cameras are not that different (6.5 mpix for 10D, 5.6 mpix for E-1),
so that cannot be the whole answer. The pixels are square, being
7.38 micron for 10D, and 7.03 micron for the E-1, computed from
specsheet sensor size in millimeters and in pixels. (The active area
of the pixels will be smaller than these footprint sizes.) The
difference in pixel footprint area is about 10%. The 10D uses a CMOS
sensor, while the E-1 uses a CCD, but these technologies are neck in
neck. All in all, one would expect substantially similar raw optical
performance, unless one chip is far noisier than the other, which
seems unlikely in competing products from major camera manufacturers.
I would have to guess that the 10D does far heavier averaging,
especially in flat areas, reducing noise at the expense of color
fidelity. It appears that the 10D may have gone too far in this.
> > >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.
>
>E-10 was famous for dynamic range. I believe it is comparable to E-1, but E-1
>has the better noise level. Here is another one, it is only slightly
>underexposed.
>Check the histrogram and note the shadow area - you will know what I mean,
>shadow can always be safe but not highlight.
>
>Setting: low contrast and softest sharpness.
>
>http://www.accura.com.hk/P5301309.jpg (1.2MB original pixel)
On my computer, the brightness is normal (not dark), and it does seem
to have excellent shadow detail, but I fear that the low contrast
scene is not a sufficiently stringent test. The low sharpness also
tends to diffuse whatever highlights there are, reducing the peaks.
In expanded view, with 3mm pixels, I do see very slight sharpening
artifacts at edges, especially horizontal edges, and the edges are
2-4 pixels wide, which goes a long way towards elimination of edge
artifacts.
Film has always had some degree of edge sharpening, due to diffusion
of fresh and exhausted developer between adjacent areas of high and
low exposure, so we are to some degree trained to expect edge
sharpening. The less aggressive the agitation during development,
the more pronounced the sharpening effect.
> > 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.
>
>I have reduced the image size by 50%, so it looked good.
Ahh. This would have the effect of oversampling the remaining image,
which will smooth the edges nicely. It also tends to reduce noise.
Was this done in the camera, or later, in your computer?
Joe Gwinn
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