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10-27-2009, 10:14 PM   #1
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K7 & KX picture comparision take 2 (RAW & Jpegs available for download)

So, last time I had some people criticize my efforts to try and give a fair comparison between the K7 and the KX. As far as I know, there has not currently been one real side by side comparison other than my previous one.

I took the advise I was given and went to re shoot.

The only thing I wish I did differently this time was I wish I had used MTF priority to discover the best aperture setting for the lens (which is f/4.0) Sorry =( I did shoot using F/5.6 so I hope that is okay with you.

Because this is a very big hassle to the camera store staff, I doubt I will have time to do this test again, as I *really* don't want to bother employees of another camera store.

Please note, Image Quality is very subjective, so I have uploaded both the RAWs and the Jpegs for you to download and compare for your selves.

The test conditions:
Tripod, 16-50mm DA* lens f/5.6@ 50mm, Av mode, RAW+, AWB, Single point (center) focus, and multi metering exposure, no EV compensation. Jpeg was at the max stars for the K7 and KX.

K7:
ISO 100-6400 using default settings and most aggressive settings (High NR start at ISO200)
KX:
ISO 100-12800 using default settings and most aggressive settings (High NR start at ISO400)

The environment this time was more of a dimly lit store, there were some bright lights pointing at really reflective objects so both cameras exhibited some minor blown highlights, but nothing major.

Image Quality:

Again please note, Image Quality is very subjective, so I have uploaded both the RAWs and the Jpegs for you to download and compare for your selves.

Jpeg Standard NR files the K7 seems to produce sharper, more detailed pictures, than the Kx, they both also have slightly different white balances, the K7 being darker.

At ISO800, the K7 has more noise, but again it's much more detailed, the Kx seems to be soft. This is also the case at ISO1600, and for both these ISOs I prefer the extra detail the K7 has to offer.

at ISO3200 it is the same case as the above, but it is now getting harder to debate which one is 'better'. K7 has more detail, but more noise, and Kx is much softer but less noise. I have not tried post processing any of the images, but post processing on the K7 might yield better images.

ISO6400 the KX is better than the K7.

KX is the only one with ISO12800 so it wins by default here.

With the Max NR on both the K7 and KX Again the K7's images are sharper and more detailed, again the K7 seems to have slightly darker pictures using AWB. Up until ISO800 I would say the noise levels between the two are the same.

At ISO1600 the K7 has more noise, but it is not by a huge amount, especially considering you are getting more detail with the image.

ISO3200 I would say is the same with ISO3200 on the normal settings. K7 more noise, but more detail, and KX less noise, but also less detail.

ISO6400 the KX is IMO much better than the K7, by a larger margin than with just the standard NR settings.

KX is the only one with ISO12800.

Overall conclusions for Jpeg quality: The quality of the K7 IMO because overall it produces more detail. It isn't really until ISO3200 where IMO that the Kx could be debated to be better.

So if you shoot often at ISO6400+ and like to use the in-body jpeg processing then get the KX.

I prefer to shoot RAW and then post process everything, I have not compared the RAW images to each other.

DOWNLOAD LINK:

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10-27-2009, 10:50 PM   #2
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Wow, the K-7 looks so much sharper than the K-x. What did you focus on? Did you use center AF point on both? Image sharpness settings the same? I am surprised at how the K-x performs here! I don't think I have ever seen such differences in sharpness between two DSLR sensors before.

ISO is as expected. Thanks for re-doing the comparison!
10-27-2009, 10:59 PM   #3
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Dear Daemos, download 4 files (2+2) at ISO100 and 1600 from K-x and K-7 at
filefactory. Please!!!
megaupload is not working for me.
10-27-2009, 11:04 PM   #4
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QuoteOriginally posted by Eruditass Quote
Wow, the K-7 looks so much sharper than the K-x. What did you focus on? Did you use center AF point on both? Image sharpness settings the same? I am surprised at how the K-x performs here! I don't think I have ever seen such differences in sharpness between two DSLR sensors before.

ISO is as expected. Thanks for re-doing the comparison!
Single focus point (center) on both, since the tripod was pointed in the same direction and height, I believe I was focusing on the same thing.

Again the KX does not have a focus indicator and that is ANNOYING.

Image sharpness was set to whatever 'natural' is set to. I was in a rush, so I assumed everything is on default.

But even comparing the RAWs the using Adobe Camera RAW the K7 is far sharper. The RAWs should be what the sensor captures so it should not be affected by those settings.

10-27-2009, 11:05 PM   #5
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QuoteOriginally posted by ogl Quote
Dear Daemos, download 4 files (2+2) at ISO100 and 1600 from K-x and K-7 at
filefactory. Please!!!
megaupload is not working for me.
I am uploading it to another site as we speak. I'll post that link, if that doesn't work I will upload what you ask =)
10-27-2009, 11:06 PM   #6
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QuoteOriginally posted by Daemos Quote
ISO6400 the KX is better than the K7.
Very interesting results.
The difference at ISO6400 is very obvious and understandable. ISO6400 on the K-7 is an "Expanded Sensitivity" which basically means its done by digital processing , even for the RAW. The hardware-based amplification ends at ISO 3200 for the K-7.

For the K-X, the Expanded Sensitivity is at ISO 12800 - one full stop higher.

I think the conclusion is -
If High ISO performance is Very Important , get a K-X
For the very best detail under moderate shooting conditions - below ISO1600 - the K-7 wins.
If you need very good High ISO performance AND the very best IQ - I guess an FF camera will fit the bill.

Last edited by kittykat46; 10-27-2009 at 11:22 PM.
10-27-2009, 11:13 PM   #7
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lol I will try to retest again if I get the opportunity. I'd like to try everything at f/4.0 and get other things to look at.

I feel bad for the camera store staff, so i'll need to go to a store I have not been to yet lol...

Last edited by Daemos; 10-27-2009 at 11:21 PM.
10-27-2009, 11:27 PM   #8
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**I have found a small flaw in my testing**

The K7 on natural had sharpness set to neutral (0) where the KX had sharpness set to Soft (1) which means the K7 had a +1 in sharpness.

However, using Pentax DCU v4 I have set the sharpness to -1 and honestly it basically looks the same. Even setting it to the maximum -ve sharpness (-5) for the K7 raw there is still more detail in that picture than the KX one.

10-27-2009, 11:29 PM   #9
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If you re-test, I think you should go up to f/8 or so to expand the DoF so we can compare more objects. But don't go if its any trouble!
10-27-2009, 11:31 PM   #10
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QuoteOriginally posted by Daemos Quote
**I have found a small flaw in my testing**

The K7 on natural had sharpness set to neutral (0) where the KX had sharpness set to Soft (1) which means the K7 had a +1 in sharpness.

However, using Pentax DCU v4 I have set the sharpness to -1 and honestly it basically looks the same. Even setting it to the maximum -ve sharpness (-5) for the K7 raw there is still more detail in that picture than the KX one.
Yeah that probably wouldn't make too much of an impact, I only looked at JPEGs so far though and not the RAW yet as I don't have a converter on this computer. Thanks for the observations! This should settle down the K-7 owners
10-27-2009, 11:32 PM   #11
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QuoteOriginally posted by kittykat46 Quote
Very interesting results.
The difference at ISO6400 is very obvious and understandable. ISO6400 on the K-7 is an "Expanded Sensitivity" which basically means its done by digital processing , even for the RAW. The hardware-based amplification ends at ISO 3200 for the K-7.

For the K-X, the Expanded Sensitivity is at ISO 12800 - one full stop higher.

I think the conclusion is -
If High ISO performance is Very Important , get a K-X
For the very best detail under moderate shooting conditions - below ISO1600 - the K-7 wins.
If you need very good High ISO performance AND the very best IQ - I guess an FF camera will fit the bill.
Gordon reported that above something like 1600 or so it's all digital anyway, based on his study of the read noise and such. *shrug*
10-27-2009, 11:34 PM   #12
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QuoteOriginally posted by Daemos Quote
I am uploading it to another site as we speak. I'll post that link, if that doesn't work I will upload what you ask =)
Need just 4 RAW
10-27-2009, 11:39 PM   #13
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QuoteOriginally posted by ogl Quote
Need just 4 RAW
okay np, I will add that to another archive for you.
10-27-2009, 11:39 PM   #14
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I can't understand it when people say an image has 'more noise but more detail'. Noise fundamentally destroys/replaces detail. And applying NR on a image with underlying noise destroys even more detail.
10-27-2009, 11:44 PM   #15
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QuoteOriginally posted by rawr Quote
I can't understand it when people say an image has 'more noise but more detail'. Noise fundamentally destroys/replaces detail. And applying NR on a image with underlying noise destroys even more detail.
well the image does have more noise, but there is more detail in the image esp when you are looking at things like text, you can make out the words much better. I consider that to be detail.
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