K7 and Kx at up to 800 ISO


Link Posted 10/05/2010 - 19:52

I have a Kx and am thinking of upgrading to a K7. The use of AA batteries on the Kx is beginning to get the better of me but that is not for this thread.

What I wonder is whether there is a difference in image quality one against the other between these cameras at up to 800 ISO (I shoot to raw). From what I've read I'm sure both are very good at 100-200 ISO. Actually I often shoot in museums at 1600 ISO and the Kx is clearly quite good at that. I'm particularly interested in 400-800 ISO as I use this quite a lot, particuarly 400 ISO, either to keep up the shutter speed in street photography or when using my macro lens with flowers or critters blowing about on a windy day. Is there any difference which might require more post-processing? I'm not really interested in tiny pixel-peeping differences, though. One would expect some difference in the result between different sensors anyway, at a guess.

These are the ISOs that concern me. I am not trying to start a thread about high ISO performance which has been done to death and which I don't use anyway (3200 and over). I'd guess that about 45% of my shots are at 200, 45% at 400 and the rest at 800 or 1600.

Last Edited by mecrox on 10/05/2010 - 19:52


Link Posted 11/05/2010 - 23:49

This is interesting to me too.

I upgraded to a KX from a Canon G9 in January (1600 shots and two sets of Lithiums later) I'm still learning and mostly using AV mode with a fixed 200 ISO unless light or movement require otherwise. I find using the flexible ISO option limited to 1600 quite acceptable as I rarely print above A4. I find left to its own devices the camera gravitates to 800 most.

Compared to my point and shoot, which I had to keep to 200, I'm very pleased with the results.


KX, standard and short zoom kit DAL lenses plus Sigma 10 to 20 which is excellent


Link Posted 12/05/2010 - 07:49
from what I've read, I'd be using a K-x and not a K-7 at ISO800. I do not see any massive improvement on noise in the K7 over even the K10D.

I've played with both a K7 and Kx in the local store and I can see the noise at ISO800 on a K7. I can't see it on the kx. I'd stay where you are if it's that important.... or invest in good software.

my pics: link
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.


Link Posted 12/05/2010 - 14:47
Many here with a k20D or K7 (same sensor) say they shoot up to 1600 ISO quite comfortably with their camera, so it should be able to give acceptable results for what you are looking for.

Still like Bret says the K-X is better at high iso and the camera will do you fine for low ISO as well. I would rather wait for the next "pro" model from Pentax which is quite likely to come the end of this year.

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55


Link Posted 12/05/2010 - 18:02
Thanks for the responses, chaps. I think the idea then is "hang on" till later in the year. I guess that in terms of my usage, moving to a K7 might be a pretty expensive sideways shift rather than an upward one as I don't really need many of the bells and whistles on the K7. I live in a town full of interesting gems, but many are in dimly lit old rooms so higher ISO does count a bit. FWIW I mainly use ACDSee Pro software to process from raw. So far very good and something of a bargain pricewise compared to some offerings.


Link Posted 12/05/2010 - 22:51
I mainly use ACDSee Pro software to process from raw

You might like to try Lightroom Beta 3v2 and compare. It has a really good noise reduction tool in the Develop module. It really can clean up High ISO noise (I have K7)


Edit - LR 3 as a beta version is free to try - I have ACDSee as well and for me LR is better at the RAW conversion
Last Edited by alfpics on 12/05/2010 - 22:52


Link Posted 12/05/2010 - 23:10
mecrox wrote:
I guess that in terms of my usage, moving to a K7 might be a pretty expensive sideways shift rather than an upward one...

I wouldn't call it a sideways shift. K7 is much more versatile than the K-x and a totally different camera, imho. For example, the K-x has no connector for a wired remote, which is essential for long exposures.

I use the K20D myself, and can not imagine to step "down" to a K-x or K-m.
Best regards

K20D, Optio I10, DA 18-55 1:3.5-5.6 AL II, A 1:1.7/50, D FA 1:2.8/100 Macro, Sigma 70-300 1:4-5.6 APO DG Macro, Pentax AF 360FGZ


Link Posted 13/05/2010 - 00:03
I paid 549.99 for my KX with two lenses (the short telephoto zoom option)

I think it's extraordinary value for money and allowed me budge to go buy my Sigma 10 to 20. My son has a K20D which impressed me & persuaded me to have a Pentax SLR 35 years after I used to sell them.

Neither of us feel terribly short changed and both of us feel we have much to learn about getting the best out of our kit.

The dearer cameras have real pentaprisms,better LCD screens and of course a lot of direct buttons.

I've found the KX superb for dynamic range, shadow adjustment, pncushion and vigetting correction,low light,log life lithium batteries easy manual focus & very compact in use with very intuitive controls.

ohh and its fun!
Last Edited by wvbarnes on 13/05/2010 - 00:03
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