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11-03-2010, 08:03 AM   #16
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QuoteOriginally posted by falconeye Quote
Please have a look at this:

(click and view in size "O")

The rightmost column, rows 2 and 3, compare K-x and D5k at ISO 12800 (D5k by boosting ISO 6400). You can see how the K-x has a "dampened" noise floor but text looks just a bit smoother too. This is the same situation but for Sony's 12MP chip. Moreover, DxO confirms that raw NR is still applied for the K-r.

Would you see a similiar difference in your K-5/D7k comparison?
The "blotted" noise effect (it figuratively appears as though someone took a damp cloth and pressed it against what was likely a higher-frequency original noise) that is present on the K-x and D5k (though the D5k shows more occasional high-luminance artifacts, probably the algorithm was trying to preserve detail and ended up preserving random high-luminance dot-noise) in these shots are NOT present (or are so subdued as to be not readily apparent) in either RAW sample I looked at from the D7K or the K-5. A few minutes ago, I compared the RAW samples on IR for the D7K, D3100, D90, and 7D (all at 6400) and found the following:

*The 7D has the worst noise levels and there appears to be some attempt to blot out the noise (though it still left tons of noise and more prevalent random noise "spiking", like a hot pixel but too frequent to be so simply explained)
*The D90, IMO, was just ahead of the 7D, with the blotchy noise similar to the D5k sample you linked.
*The D3100 was just ahead of the D90, but had an even consistent noise grain to it, showing minimal NR, but with a prevalent deep-red noise pattern that creates a color cast that is unattractive.
*The D7000 was in the lead, with a similar noise pattern to the D3100 (very consistent, with no chroma smearing visible), though amazingly less per-pixel noise than the D3100. The strong red color cast present in the D3100 is not in the D7000, despite them both being same-generation Exmor sensors. That was the most surprising result.

I agree, the K-x NR is obvious...it looks unnatural, but I'm sure it subdues noise for the most part. I simply don't see the same effect on the K-5 samples (limited few I've seen) or any of my D7000 shots. If there is secondary NR, its VERY, VERY well hidden.

In looking at the D3100 and D7000 side-by-side, it makes me wonder if something was employed in the D7000 to mitigate the strong red noise to reduce color cast, but I have no proof one way or another.

To be fair, DXO should make a similar comment regarding the D5k/D90 in terms of smoothing. It's clear if you look at the SNR curve or any images that there is some obvious NR being applied at ISO3200+.


Last edited by AngryCorgi; 11-03-2010 at 08:11 AM.
11-03-2010, 08:29 AM   #17
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I'm not saying there CAN'T be any K-5 secondary NR...just saying that I can't see it in comparison with its cousin.
11-03-2010, 09:11 AM   #18
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QuoteOriginally posted by AngryCorgi Quote
I'm not saying there CAN'T be any K-5 secondary NR...just saying that I can't see it in comparison with its cousin.
That's understood and your post is appreciated.

Looking at the latest DxO figures for D5k, K-x and K-r, it seems that raw NR from Nikon is less obvious in the figures (if done at all).
DxOMark - Compare sensors
and click the SNR tab.

However, D5k and K-x have about the same SNR at ISO 6400 because Nikon 6400 are not Pentax 6400. So, what Pentax wins on NR does Nikon win on ISO cheating K-r still seems to apply raw NR, but a bit less than K-x.

Will be interesting to see real lab tests for K-5 and D7k. Maybe, Pentax doesn't do raw NR anymore. After all, the K-5 sensor shouldn't require it
11-03-2010, 09:30 AM   #19
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QuoteOriginally posted by falconeye Quote
That's understood and your post is appreciated.

Looking at the latest DxO figures for D5k, K-x and K-r, it seems that raw NR from Nikon is less obvious in the figures (if done at all).
DxOMark - Compare sensors
and click the SNR tab.

However, D5k and K-x have about the same SNR at ISO 6400 because Nikon 6400 are not Pentax 6400. So, what Pentax wins on NR does Nikon win on ISO cheating K-r still seems to apply raw NR, but a bit less than K-x.

Will be interesting to see real lab tests for K-5 and D7k. Maybe, Pentax doesn't do raw NR anymore. After all, the K-5 sensor shouldn't require it
Yeah, the SNR curve from the D5k looks pretty uniform. I tend to trust DXO and don't subscribe to the conspiracy theories about how they operate. On the other hand, when I look at RAW images from the D5k and D90 (particularly in the shadows) my eyes are telling me something's fishy. The luminance noise being inconsistent and smeariness to the chroma just seems unnatural.

And you're right, the K-5 shouldn't need additional NR. The 16MP Exmor seems to be quite a good performer naturally, assuming the D7000 isn't cooking the RAW.

11-03-2010, 09:44 AM   #20
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QuoteOriginally posted by falconeye Quote
Will be interesting to see real lab tests for K-5 and D7k. Maybe, Pentax doesn't do raw NR anymore. After all, the K-5 sensor shouldn't require it
Do you still own a K-7?

I'm trying to gather RAW data from as many camera's as possible to see if I can't compile a conclusion on identifying RAW NR with Pentax camera's.

So far all I have is the K20D and K-5.
I'm trying to get: K-x and K-r and K-7 data.

ISO200 exposed at: 1600, 3200, 6400, 12800
11-03-2010, 10:36 AM   #21
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QuoteOriginally posted by AngryCorgi Quote
Pure poppy-cock...I am looking at ye ol' Dino shot at ISO200 with no chroma NR applied at import and there is the same ever-so-slight chroma pattern in the midtones that the D7K shows. Pushed 1-1/2EV, and the chroma shows clearly in the shadows. This is the same behavior I'm seeing with the D7K (and pretty much every other camera I've ever owned...D700, D3100, D90, 30D, XT, XSi, 1D2, 5D...all show some chroma in shadows when pushing ISO200 files, all to varying degrees of course).

Not trying to burst any bubbles here...the K-5 images look fantastic, but I seriously can't say it looks any different than the other cameras with the 16MP Exmor in them.
Since the RAW sample(dino and car) is over 1 stop underexposed I think this is most likely the reason you are seeing noise at this level.

However, If we take a properly exposed ISO200 image, we will find no chroma noise in the shadow regions whatsoever(or to the naked eye). Having said that, this also exonerates the D7K to an extent as well since the RAW samples produced by IR are underexposed as well. Maybe not as much as the Dino(per say), but underexposed nonetheless.

To help establish this, please consider the following samples:

DINO HISTOGRAM:


BILL HISTOGRAM:


DINO NOISE MAP 500%:


BILL NOISE MAP 500%:


Pixel peeping, full size images here: Dino & Bill

...repaired full size image links

/... the end

Last edited by JohnBee; 11-03-2010 at 11:08 AM.
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