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10-22-2010, 04:08 PM   #1
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DXOMark evaluates the 645D

DXO Labs have bench-marked the 645D on dxomark.com.

DxOMark - Pentax 645D

It is now the 5th highest ranking sensor in the DXOMark database, after the Phase One P65 (first) Nikon D3X (second), Phase One P40 (third), 645D & Nikon D3s (equal fifth). Not a bad result for Pentax.

I guess this also means DXO Optics Pro support for the camera may be in the pipeline too.


Last edited by rawr; 10-22-2010 at 04:18 PM.
10-22-2010, 06:03 PM   #2
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Prediction checkpoint

Great news and an interesting read!

I cannot but must remember my post back in March when I predicted the DxO measurement of 645D dynamic range when it gets published.

I predicted 12.7 EV while DxO now publishes 12.6 EV. That's not bad in my book


There's only one "better" camera which beats the 645D in overall score: D3X. But of course, the D3X is faster while the 645D has the better resolution.

Last edited by falconeye; 10-22-2010 at 06:21 PM.
10-22-2010, 08:39 PM   #3
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QuoteOriginally posted by falconeye Quote
I predicted 12.7 EV while DxO now publishes 12.6 EV. That's not bad in my book
The kodak white paper I read on this sensor quotes the sensor DR as being 11.5 EV. Kodak always tend to be conservative in mentioning performance capabilities in their sensors. If only they had this trait when they rated t-max100, which is actually a ISO64 speed film, but I digress....
10-22-2010, 10:58 PM   #4
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The measured and indicated ISO are almost the same. It's rarity now...
If we compare with FF camera, we will see that FF's ISO is inflated too much.

DxOMark - Compare sensors

645D - measured 1613/manufacturer ISO 1600
A900 - 1254/1600
Canon 5D Mk II - 1093/1600....

645D - 824/800
A900 - 615/800
Canon 5D Mk II - 564/800

e.t.c.

10-23-2010, 07:49 AM   #5
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QuoteOriginally posted by falconeye Quote
Great news and an interesting read!

I cannot but must remember my post back in March when I predicted the DxO measurement of 645D dynamic range when it gets published.

I predicted 12.7 EV while DxO now publishes 12.6 EV. That's not bad in my book


There's only one "better" camera which beats the 645D in overall score: D3X. But of course, the D3X is faster while the 645D has the better resolution.
Very impressive, good to hear. Goes in line with the hands-on reviews by people
10-23-2010, 10:29 AM   #6
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Great to see, would love to have one. It makes the D3X look like a complete bargain as it retails at more than half of the 645D here in the UK.
10-23-2010, 10:48 AM   #7
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Is the DxO test anything but another set of meaningless numbers?

Is the DxO test anything but another set of meaningless numbers?

The numbers show the Pentax K-x outperforming the Leica M9. Sort of hard to believe that we would see that confirmed in real-life photography:

DxOMark - Compare sensors
10-23-2010, 11:28 AM   #8
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QuoteOriginally posted by Ole Quote
Is the DxO test anything but another set of meaningless numbers?

The numbers show the Pentax K-x outperforming the Leica M9. Sort of hard to believe
The DxO numbers are accurate in this case.
But note that the M9 has the better resolution and together with it's ranger finder focus system and lenses may yield sharper images. Something DxO does not consider on purpose.

10-23-2010, 12:21 PM   #9
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It's quite reasonable that the (Sony CMOS) K-x sensor has some properties that exceed the performance specifications of the (Kodak CCD) M9's.

I think we also see that in real-life photography Some people are getting exceptional results out of the little K-x that rival much more expensive hardware.

As DXO says of the M9:

In comparison with the sensors used by other full-frame main manufacturers, the pixel quality of the Leica M9 sensor remains low. The results of the Leica M9 are very close to the measurements for the Canon EOS 5D, launched four years ago. The Leica M9 provides good image quality for low ISO, but its results for high ISO are weak, with dynamic range decreasing very fast. So its Lowlight ISO score is a little disappointing, especially for this type of camera. The Leica M9 achieves the lowest score among measured full-frame sensors.
10-23-2010, 09:37 PM   #10
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QuoteOriginally posted by rawr Quote
It's quite reasonable that the (Sony CMOS) K-x sensor has some properties that exceed the performance specifications of the (Kodak CCD) M9's.

I think we also see that in real-life photography Some people are getting exceptional results out of the little K-x that rival much more expensive hardware.
[/I]
In real life photography we see that K-x has no any chances against FF M9.
To say honest, K-x is worse than M9's in terms of colours, contrast, resolution and IQ in whole.
If you say about lower noise of K-x...Noise level at high ISO is not the main characteristic of IQ.
But...under DXO datas K-x has worse Low-Light ISO limit than M9:
811 vs 884.

What do you mean?

DXO Mark doesn't say anything about real photos.
10-24-2010, 12:44 AM   #11
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QuoteOriginally posted by ogl Quote
What do you mean?
DXO Mark doesn't say anything about real photos.
I was just gently bouncing back Ole's point about DXOMark's numbers being reflected in real life photography.

If DXOMark says the K-x sensor exceeds the performance of the M9's in dynamic range and color depth, but not high ISO, I have no reason to doubt that this is accurate. But the DXO Mark numbers just show sensor performance. On top of the sensor sits the rest of the camera - sensor size, lenses, shutter, firmware, imaging engines etc - which also contribute hugely to real life IQ. So as an imaging system, a M9 may indeed produce better photos than a K-x in real life.

Alas when talking real life photography you get into a whole bigger discussion, where lenses, photographer experience, and a zillion other variables may intersect and influence the outcome. But the sensor is the core of a digital camera, so objective tests of sensor performance are useful, even if they do sometimes challenge our expectations.
10-24-2010, 01:34 AM   #12
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QuoteOriginally posted by ogl Quote
DXO Mark doesn't say anything about real photos
I own a M9 and while I cannot speak about the image quality from the pentax K-X, I can speak volumes about the image quality of the Leica M9. My nikon D3s kicks the crap out of the M9 at ISO400 and up, the only saving grace of the Leica is that the lenses are much faster and are noticeably sharper than SLR lenses.
10-24-2010, 02:42 AM   #13
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QuoteOriginally posted by rawr Quote
I was just gently bouncing back Ole's point about DXOMark's numbers being reflected in real life photography.

If DXOMark says the K-x sensor exceeds the performance of the M9's in dynamic range and color depth,

I don't see good colours of K-x vs M9. DR - yes, maybe.
10-24-2010, 02:44 AM   #14
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QuoteOriginally posted by Digitalis Quote
I own a M9 and while I cannot speak about the image quality from the pentax K-X, I can speak volumes about the image quality of the Leica M9. My nikon D3s kicks the crap out of the M9 at ISO400 and up, the only saving grace of the Leica is that the lenses are much faster and are noticeably sharper than SLR lenses.
I prefer weak AA filter (or no AA filter)
with good sharpness + outstanding lenses than high ISO.
D3s has 12 MP CMOS, M9 has 18 MP CCD.
10-24-2010, 04:10 AM   #15
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QuoteOriginally posted by ogl Quote
I don't see good colours of K-x vs M9. DR - yes, maybe.
Again, just refer to DxO.

As much as I criticize DxO for its four overall scores, as much do I praise them for the quality and width of work when it comes to sensor evaluation.

First, really read all of DxOMark - Measurements and DxOMark - Canon 500D/T1i vs. Nikon D5000, and then visit each and every of the eight (non overview) measurement pages, especially the last three which are absent from the comparison pages!

Of course, nobody forces you to do it. But if you don't, you better don't criticize DxO because then it is ridiculous. They have no peer. I do criticize some of the testing procedures (e.g., the lack of check if spatial frequency dependencies are modelled correctly) but at the same time, I acknowledge that nobody even comes close yet.

As for good colors.

First and most of all, colors are defined by the raw converter and can be adjusted to personal preferences, also in camera. That's 90% of the beef and argueing which camera has the better colors then doesn't make a lot of sense.

As for the remaining 10%, it all comes down to a narrow enough spectral channel sensitivity which increases noise but reduces color metamerism.

DxO goes as far as actually measuring the ISO 17321 sensitivity metamerism index after optimizing the color response to be as good as possible (using their own raw conversion process and calibration).

It is 76 for the M9 and 82 for the K-x. So no, the M9 doesn't have the better colors. For detailed results, inspect the Full CS data.

However, because sensitivity metamerism indices around 80 and higher are almost impossible to distinguish by the naked eye except in a controlled setup, a look at the color sensitivity curves is equally important. And here, K-x and M9 perform almost identically. Add to it the higher resolution of the M9 and DxO measures a better overall image quality. Just don't get fooled by the overall score.
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