At 3:34 AM +0200 6/2/04, Listar wrote:
>
>From: "C.H.Ling" <chling@xxxxxxxxxxxxx>
>Subject: [OM] Re: Dynamic range of films (and digits)
>Date: Tue, 1 Jun 2004 22:56:49 +0800
>
>
>----- Original Message -----
>From: "Joe Gwinn" <joegwinn@xxxxxxxxxxx>
>
>>
> > Isn't 10D one of those C*n*n thingeys? Wash your mouth out with soap!
>
>To show my Olympus loyalty, I have already sold the 10D ;-)
Your honor is restored. A close call....
> > 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.
>
>May be the Olympus circuit is noisier; the signal amplifier circuit also plays
>an important role.
I'm sure the details are a trade secret, but none of these sensors
are close to the theoretical limit (photon shot noise), instead being
limited by electrical self-noise of one kind or another. My
impression is that this is often in the image sensor itself, rather
than the amplifier. I base this on the observation that astronomical
CCD sensors are often limited more by CCD self-noise than photon
noise, and these CCDs and amplifiers are the best that can be built
with current technology, for any amount of money.
> > 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.
>
>May be. For the DCs I have used, Olympus has the most noise in images. It is
>including the C2000, E-10 and 5050. At the same time other makers have better
>noise control but none has the overall quality that Olympus provided. I'm
>still using the 5050; beside noise, the image quality is great!
The bottom line seems to be that color fidelity (and perhaps tonal
resolution) turned out to outweigh noise. For me, this is the most
interesting result so far. Many people have focused on noise, or the
lack of noise, and this may have been misdirected.
In a sense, I should not have been surprised. In the old days, when
silver-based film was king, we basically didn't notice a little
grain, but if the colors were off, we really complained.
> > >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.
>
>The original scene was not really low contrast as indicated by the blue sky.
>In my experience most slides will not be able to provide this capture range.
Seeing only the photograph, it's hard to see what the original
brightness range was. You have the experience there; I would assume
that your judgement that slide film would be exceeded is correct.
I just assumed that because the British like rainy, overcast places,
they chose Hong Kong, which explained why there were no sunlit photos.
If you have a handheld spotmeter (or an OM-4), it would be easy to
quantify the original brightness range. Even the experienced eye
isn't all that accurate in estimating true brightnesses.
> > >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?
>
>It was done by PS.
Photoshop can do anything but take the picture. From earlier
postings, you take the picture in RAW mode, and do all processing in
Photoshop?
Joe Gwinn
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