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Old Mar 7, 2006, 9:56 PM   #1
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This is my 3rd day with this digicam.
& I have discovered a terrible flaw.

With exposore that is equal to or more than 1 second,
a noise removal program kicks in to remove grains.
The noise removal is too excessive, and destroys a lot of details.
see below:

(i) thus you will notice, as long as exposure time does not exceed 1 second, a greater amount of details will be preserved, the results is the same for ISO64, 100, 200, 400.
(ii) exposure starting from 1 second and onward, will lose a huge amount of details due to NR filter.
(iii) I think Ricoh should release to new firmware to address this issue. The GR lens is excellent, but this excessive filter surely ruins this camera.
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Old Mar 7, 2006, 10:00 PM   #2
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I have made a gif showing the problem:

http://luminous-landscape.com/forum/...ost&id=309

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Old Mar 8, 2006, 10:02 AM   #3
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Your test is so flawed, that it's impossible to draw any conclusions from it.

For one thing, the exposure is all over the place. Noise levels, dynamic range and detail will suffer if you underexpose.

Given the same lighting, you'd need to make sure you compensate with a one stop smaller aperture, each time you double the shutter speed (to slower speeds) if ISO speed is the same. Given the settings I see for shutter time, aperture and ISO speed, exposure doesn't match up (unless you were also changing the lighting, which will also impact noise, dynamic range and detail).

Your White Balance also looks different between photos (although some of that is just underexposure).

You'd also need to make sure you're using a tripod with the same focus for each shot. Even then, you can get camera shake from pressing the shutter button if you don't use a self timer or remote cord release (and unless you use manual focus, you may still have differences that can make the test invalid).

Even then, you'd only be showing differences based on shutter speed and aperture differenes. To compare detail with and without noise reduction, you'd need to take photos exposed identically (lighting, subject, focus distance, aperture, ISO speed, shutter speed, white balance) with and without noise reduction (and if you can't disable it, you can't perform that kind of test).

Also, noise reduction systems during long exposures are not designed to remove random grain/noise. They're designed to remove hot pixels.

They take two photos, with one simulating a lens cap on exposure.

This is known as "dark frame subtraction". The system works by looking for hot pixels in the dark frame exposure, then removing them in the actual exposure by replacing them with values interpolated from adjacent pixels. It knows where to find them in the actual exposure by looking at the dark frame exposure taken at the same time.

Without dark frame noise reduction, it's not uncommon to have hundreds of hot pixels on longer exposures. With cameras equipped with it, you just don't see them.

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Old Mar 8, 2006, 2:07 PM   #4
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JimC wrote:
Quote:
Your White Balance also looks different between photos (although some of that is just underexposure).

Thanks for bringing that up, White Balance was on auto, thus that also shows GR Digital's white balance isn't exactly perfect nor do I expect it to be.
And this post isn't about color temperature.

You'd also need to make sure you're using a tripod with the same focus for each shot. Even then, you can get camera shake from pressing the shutter button if you don't use a self timer or remote cord release (and unless you use manual focus, you may still have differences that can make the test invalid).

Yup, it was mounted on a tripod, otherwise what's the point?
Exposures were taken with the 2 sec self timer to avoid shake.

Even then, you'd only be showing differences based on shutter speed and aperture differenes. To compare detail with and without noise reduction, you'd need to take photos exposed identically (lighting, subject, focus distance, aperture, ISO speed, shutter speed, white balance) with and without noise reduction (and if you can't disable it, you can't perform that kind of test).

GR Digital doesn't have the option for you to switch on or off NR.
The point here is, as soon as exposures are 'equal or to greater than one second' automatic NR filter kicks in to remove noise. But it's too agressive.


The tests made above shows that Ricoh's engineers made a decision to implement an overly agressive NR filter that degraded the photo.

Tests shows that within the difference of one stop, there were significant loss in image quality. & it has nothing to do with the lens nor the CCD. Rather the implementation of the Ricoh GR Engine.

Also, noise reduction systems during long exposures are not designed to remove random grain/noise. They're designed to remove hot pixels.


NR reduction encompasseth several things.
NR could include luminance noise filter, unsharp, dark frame,
Most camera makers won't tell you exactly what they do,
but you can always guess . . .
Here, there was an luminance NR filter applied to remove random noise,
& it was too agressive creating banding and softening of the image. . .


Also per the manual,
dark frame subtraction for the GR-Digital
doesn't starting until exposure are longer than 15 seconds.

The problem is truely one caused by an overly agressive NR filter.
& an in camera option to tweak or switch off completely that filter would be great.
Most Nikon & Canon's have that option.
& it wouldn't hurt for Ricoh to add that in the next firmware update.





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