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10-26-2009, 11:01 PM   #1
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Pentax K-7 & K-X: My picture comparision (RAW & JPEG) Download link for RAWS

I had a bit of time today, and was able to go into a camera store and try out the K-X, I brought along my K-7. I shot with a tripod and used my DA* 16-50mm lens @ 50mm.

Did a test from 100-6400 ISO using the K7 and 100-12800 ISO using the Kx. all the shots were taken in Av mode with a f/22 (for widest depth of field) although I did use a tripod, I basically focused and clicked and then stepped away from the tripod, there is potential for some blur (esp at the lower ISOs)

I tried to make it as perfect as possible attempting to recreate the conditions to be identical.

As I was in a rush, after I had time to play around with everything I noticed some problems:

-I used auto white balance on the K7, I thought I set the KX to auto but the EXIF says differently, so it was set to whatever it was put on. This may or may not have an impact on image quality.

-I set both to the same color profile, but the K7 had -1 sharpness.

-I took pictures and marked the K7 Jpegs with NR on High (starting @ 200) and default NR settings. I did the same with the Kx, but I forgot to jot down everything, so I'm unsure of which jpegs are which so I'm only going to be uploading the raws)

My general usage of the cameras: I like the K7 and feel it's build and features surpass the Kx in every way. But I'll just list the cons of the Kx I really DON'T like:

-Viewfinder doesn't display as much info
-No AF indicator in the viewfinder
-No top LCD screen (the K7 is my first camera I have EVER bought and I have found this to be useful)
-Shutter is very loud
-In Body Jpeg quality seems to be restricted to 3 stars (vs 4) I haven't played around enough to see if this makes a huge difference (but file sizes are much different)
-No Weather sealing, the reason I bought Pentax in the first place.

Overall IMO they are close enough from ISO 100-1600 the Kx seems slightly sharper, ISO 3200 the Kx definitely has the edge, but again I can't say you couldn't make them close enough with post processing. However ISO-6400...man on man huge difference.

Overall I feel IQ wise is close enough between the KX and the K7 that you should let the features that you want decide (as well as your wallet)

Anyways I'll let the pictures speak for them selves, since everyone has their own opinion.

If I get the chance to repeat this experiment I'll go into another camera store to try it out.

RAW files download links (in RAR archive format):

storage.to - Download
http://www.megaupload.com/?d=E7Q8RBE9
http://www.filefactory.com/file/a13532a/n/K7KX-RAW_rar

I personally have much faster speeds using megaupload.

Other links coming shortly as I upload them


Last edited by Daemos; 10-27-2009 at 12:24 AM.
10-26-2009, 11:21 PM   #2
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thanks for the comparison! a comparison of the NR settings would be good also to see if Pentax can put some magic into K-7's high iso.
10-26-2009, 11:24 PM   #3
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QuoteOriginally posted by Eruditass Quote
thanks for the comparison! a comparison of the NR settings would be good also to see if Pentax can put some magic into K-7's high iso.
well I have posted the RAWs, as far as I know RAWs are not affected by NR on camera settings (the raws were taking from default settings), and based on the RAWs the noise and detail are very comparable from ISO 100-1600.

Well just check out the raws!
10-26-2009, 11:28 PM   #4
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A good mini-test.
I wouldn't be too concerned about JPEG quality only going to 3 stars - it's just going to be the top quality setting (as 4 stars would be in the K-7) but just for a 12Mp file as opposed to a 14Mp file. The K100D was the same.

10-26-2009, 11:34 PM   #5
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QuoteOriginally posted by Ash Quote
A good mini-test.
I wouldn't be too concerned about JPEG quality only going to 3 stars - it's just going to be the top quality setting (as 4 stars would be in the K-7) but just for a 12Mp file as opposed to a 14Mp file. The K100D was the same.
Yeah I was going to post the Jpegs, but I am having a difficult time to figure out which settings I did with each lol...I should of written it all down. I did for the first couple K7 shots, but was quickly running out of time, so I just rushed everything after!

But if there is a request I can break down the jpegs into K7/Kx and upload them as a rar file. Unfortunately I don't think that is as accurate as testing raw vs raw as I cannot pinpoint the exact NR settings each jpeg had. Sorry guys.

as far as the star thing, a 3 star ISO 100 Kx file is 4.6 MB where a 4 star K7 is 8.45MB so there is obviously some sort of compression as just being at a 12mpix vs 14 mpix wouldn't account for the file size difference. Doing a quick test on my K7 at home on the same scene and settings: 4 stars is ~8 MB where 3 stars is ~6MB...

Last edited by Daemos; 10-27-2009 at 12:24 AM.
10-27-2009, 12:24 AM   #6
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has anyone downloaded the files yet or are having problems with the links/

Let me know!
10-27-2009, 02:30 AM   #7
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K7KX-RAW.rar - download now for free. File sharing. Software file sharing. Free file hosting. File upload. FileFactory.com
is working
10-27-2009, 03:23 AM   #8
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Dear friend, thank you for your efforts...But.
Huge disappointment...
218 MB of useless files...
How to estimate the sharpness and resolution with F22?
The difraction starts from F11 with APS-C sensor.
The best apertures are from F4 till F8.

I see only two things -
K-x has better WB and less noise at ALL ISO. IMO.

is it real to retest photos with DA* 16-50mm lens @ 50mm
at f5.6?


Last edited by ogl; 10-27-2009 at 04:26 AM.
10-27-2009, 06:19 AM   #9
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QuoteOriginally posted by ogl Quote
Dear friend, thank you for your efforts...But.
Huge disappointment...
218 MB of useless files...
How to estimate the sharpness and resolution with F22?
The difraction starts from F11 with APS-C sensor.
The best apertures are from F4 till F8.

I see only two things -
K-x has better WB and less noise at ALL ISO. IMO.

is it real to retest photos with DA* 16-50mm lens @ 50mm
at f5.6?
.

have to agree a bit - f/5.6 or f/8 may have been a better choice, but thank you any way for the effort, it's much appreciated.
10-27-2009, 06:58 AM   #10
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I don't see any problems with colours with RAW files from K-x.
LR 3.0 beta works fine with DNG. K-x's WB is better for my eyes.

I put all levels of NR in LR 3.0 to ZERO and compared K-x and K-7 - K-7 is noisier at ISO400 and above.
LR removes colour noise very good with K-7's DNG, but K-x is better and no need NR till ISO1600 for my eyes or maybe a bit.

But I can't understand anything with per-pixel resolution and sharpness with F22.

Last edited by ogl; 10-27-2009 at 08:12 AM.
10-27-2009, 07:35 AM   #11
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Daemos, thanks for the comparison. It's unfortunate other people can't simply appreciate your efforts rather than criticizing your methodology. I'm sure their comparisons will be much more thorough... well maybe not.

Anyway, thanks for the effort and it will be interesting to see how Pentax updates their ISO performance in future cameras.
10-27-2009, 08:07 AM   #12
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QuoteOriginally posted by Rich_A Quote
Daemos, thanks for the comparison. It's unfortunate other people can't simply appreciate your efforts rather than criticizing your methodology.
1. How many photos do you have at F22?
2. Can you understand the resolution with photos at F22?

Do you enjoy your correctness?

they are close enough from ISO 100-1600 the Kx seems slightly sharper
The author of thread says about sharpness of photos, but there is no sense.
10-27-2009, 08:35 AM   #13
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QuoteOriginally posted by ogl Quote
1. How many photos do you have at F22?
2. Can you understand the resolution with photos at F22?

Do you enjoy your correctness?

they are close enough from ISO 100-1600 the Kx seems slightly sharper
The author of thread says about sharpness of photos, but there is no sense.
This is the first camera he has ever bought you know!

I think we all appreciate his efforts and now he knows about diffraction!
10-27-2009, 09:26 AM   #14
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QuoteOriginally posted by Eruditass Quote
This is the first camera he has ever bought you know!

I think we all appreciate his efforts and now he knows about diffraction!
Yeah no kidding. Ogl, if you don't like this person's effort, couldn't you just ignore it? There are quite a few other reviews for you to (s)troll through - next time you could be more constructive with your criticism (hope that isn't expecting too much).

On a completely related note, I have never looked but does this forum have an ignore user option? There's this one member I would like on my ignore list...
10-27-2009, 09:41 AM   #15
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I chose F/22 because I assumed that would give me the largest DOF which I assumed would give me everything I wanted. Just to let everyone know I got my K7 Oct 16th, and opened the boxes on Oct 17th just an FYI.

I'm actually not too sure what diffraction is when it comes to photography (please bear in mind I just woke up)

As far as the WB on the Kx vs K7 I thought I had explained that alraedy...one was set to auto, the other was set to manual (Kx) and real world, the K7 actually has the more accurate colors. Just an FYI.

Ogl, if you would like to nitpick, maybe you could be helpful and try and teach me why I would choose a certain f/x number vs another for sharpness. I mean would you like me to comment english skills.

I actually have some time today, so I'll take all your advice and try to reshoot at a different store. (more dim environment) This time I will be sure to mark down all the settings =D

Last edited by Daemos; 10-27-2009 at 09:48 AM.
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