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12-17-2010, 02:34 PM   #16
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QuoteOriginally posted by pcarfan Quote
This is a focus issue...I can tell you with 1/10th of a mm movement of the focus ring the focus can change. Even at max. mag and LV the focus can never be spot on. In fact the first K-7 images were too soft and I had to redo the test.

SHARPNESS DIFFERENCE BETWEEN CAMERAS IS DUE TO FOCUS ERRORS

I will take multiple shots at iso100 and pick the best and post later.

I like my K-7 very much and frankly I am not entirely sold on jutifying having spent $1.5k on the K-5, yet....yes, it is better at very high iso (iso 6400 and 12800 are useable now) and I defintely like the fact the AF button also engages the SR (I always use the AF button to focus and disengage the shutter) and every time I had to wait for the SR, but now it seems like it's always there.

I am still testing the metering to see whether it is as vonsistant as rthe K-7, as a few shots were iffy and it seems to change between lenses (like this test needed +1EV)...the few built-in flash shots I took in Av mode and P=TTL are just fine, possibly a tad bit more exposed than the K-7 but not blown out.
I have to compare iso 1600 and iso 3200 in good daylight to see how much better it is.

I ahven't made up my mind on any AF improvements. The DR is better, but I need to test it more to finds it useability for me.
no worries mate..be nice to see the test done again with faster shutter speeds { well lit subjects} as ash has said .....thanks for the doing the test ...and thanks for being frank about your K5 purchase and not being sold on the money it cost you over the performance of the K7 yet..........makes us K7 owners feel a tad better ..LOL...cheers again for the test

12-17-2010, 04:10 PM   #17
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QuoteOriginally posted by pcarfan Quote
Thanks.... Higher shutter speed woul mean good light, which would defeat the purpose of using high iso. Both cameras got the same settings, and irrelevant of how they each handle long exposure, this tells me what each is capably.
Oh! the horrors of typing with an iphone
12-17-2010, 04:17 PM   #18
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LOL

its called big fingers , little device syndrome....
12-17-2010, 04:46 PM   #19
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QuoteOriginally posted by tommot1965 Quote
lol

its called big fingers , little device syndrome....
...........................

12-17-2010, 07:01 PM   #20
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I really appreciate your test. The main thing I noticed was the K7 has better color and contrast at lower ISOs, especially between 200 and 800.
I still suspect that the trade off for higher ISO is in color and contrast richeness, which is one of the things I like best about Pentax.
I have a friend who shoots both Pentax and Nikon, and he thinks the K5s color are better. I think they are more like Nikon's, which I shot for decades.
12-18-2010, 12:00 AM   #21
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QuoteOriginally posted by kittykat46 Quote
I found that the K-7 lost colour accuracy very quickly at ISO3200 and above.
The K-5 seems to have that under control all the way to Very high ISOs.
Actually here, even for ISO 100 color rendition is different, which one more accurate?
12-18-2010, 05:35 AM   #22
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QuoteOriginally posted by Ron Kruger Quote
I really appreciate your test. The main thing I noticed was the K7 has better color and contrast at lower ISOs, especially between 200 and 800.
I still suspect that the trade off for higher ISO is in color and contrast richeness, which is one of the things I like best about Pentax.
I have a friend who shoots both Pentax and Nikon, and he thinks the K5s color are better. I think they are more like Nikon's, which I shot for decades.
QuoteOriginally posted by yusuf Quote
Actually here, even for ISO 100 color rendition is different, which one more accurate?
The color has a lot to do with the WB as well. I had chosen Tungsten WB for both cameras and may be they deal with tungsten pre-set differently (I am sure there is even a choice of various Tungsten WB that can be chosen). I did not want to do 'auto' WB as that was quite different looking between cameras and at times between shots (slightly) as well.

The K-7 color is more accurate here for the chip box.
12-18-2010, 10:02 AM   #23
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I guess it depends upon where you're coming. I think overall, Nikon's and Canon's color is "more accurate," as well as now the K5 and Kr, but to me that also means flatter and duller (often referred to as "plastic"). Years ago, I chose Kodachrome and Fujichrome because of how they punched or enhanced to colors. When I finally decided to go digital, I looked around a lot at relatively plastic pics and decided Pentax had an edge in this department, so I switched from decades of Nikons to Pentax. I still prefer Pentax colors to Nikon or Canon, but the difference has narrowed considerably since they entered the high ISO race.
The thing is, I don't want my pictures to be exactly like the scene--I want them to be better. Better to me, is not being able to see shadow detail better than the naked eye. It's in the overall dramatic impact of the image.
Don't get me wrong. I think the K5 is a great leap ahead of previous models (especially in ISO and DR) and they may now offer the best DSLR on the market. I want one badly.
Not just WB, but lenses, lighting and other things effect this, and I'm sure I can tweak the K5 to get what I want. It's just that I'm going to have to tweak it more than in previous models.
But, from what I've seen (not just here), there is a difference in color rendition at low ISO, which is where I live.

12-19-2010, 05:11 AM   #24
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QuoteOriginally posted by pcarfan Quote
The K-7 color is more accurate here for the chip box.
Interesting. Does such difference (or inaccuracy) at low ISO exists in daylight too between k-5 & k-7?
12-19-2010, 07:44 PM   #25
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QuoteOriginally posted by yusuf Quote
Interesting. Does such difference (or inaccuracy) at low ISO exists in daylight too between k-5 & k-7?
I will test this later, when I get some time....but, frankly I think the K-5 is just fine (it's just a matter of me still getting aquainted with the camera).
12-19-2010, 08:06 PM   #26
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I used to think that the K5 was only 1.5 stop better in iso than the K5..but since the dpr review im changing that to 2.5 stops better...damn you K5....

certainly makes handheld shooting more possible in lower light
12-19-2010, 09:58 PM - 2 Likes   #27
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QuoteOriginally posted by Tommot1965 Quote
I used to think that the K5 was only 1.5 stop better in iso than the K5..but since the dpr review im changing that to 2.5 stops better...damn you K5....certainly makes handheld shooting more possible in lower light
I'd ignore the DR stuff in DPR as it's really showing the Tone Response Curve (TRC) as applied to the JPEG. Look at the raw performance as this has had no TRC applied yet. This gives you a better idea when performing PP in a raw converter of how much you can boost EV, pull up tone curves, dodge or use "fill light" before noise will become a problem.

First off, read this article discussing the 3 regions of noise: Shadow, Mid-Tone, Highlight:

DxOMark - Noise characterization

Now compare the K7 & K-5:

DxOMark - Compare sensors

DR is the ratio of the lowest usable signal (just about the noise floor) to saturation. The difference between the K-7 & K-5 is enormous (about 3 stops between ISO200-1600), 3.75 stops at ISO 100 and the K-5 can still go to ISO80 for another 0.4 stop improvement. For example, at ISO100 the K-7 at ISO100 is 10.6 EV, while the K-5 at IS1600 is 10.36 EV, a 3.75 stops difference. So the ability to dredge signal up out of for the abysmal deeps is much better with the K-5.

"The mean reflectance of a natural scene is known to be about 18%. [See http://www.experts123.com/q/what-is-the-basis-for-18-reflectance-being-the-c...-doubt-it.html] If the camera sets its exposure parameter to reach saturation on an object with a reflectance close to 100% (a “white” object), then the SNR 18% value is representative of the level of noise in the scene". So the SNR 18% chart shows us how noisy the mid-grey/mid-tones are. The difference between the two cameras in favour of the K-5 is about 1 stop between ISO100-1600.

The Colour Sensitivity is supposed to include highlight noise performance: "Colour sensitivity is an integral value over the whole curve characteristic. In particular it depends on the noise in highlights. However, it also depends on the sensor’s spectral sensitivities which determines how the sensor can see the colours of the scene." The difference is about 0.8 stops between ISO100-1600.

So summing up, typically there is about a stop difference in performance, except when you boost the shadows. For the low-ISO shooter, this ability is enormous: 3.75-4.15 stops.

Dan

Last edited by dosdan; 12-20-2010 at 01:12 AM.
12-19-2010, 10:41 PM   #28
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cheers for the reply Dan..you have educated me somewhat today..onya mate
12-20-2010, 09:02 PM   #29
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ISO from K-7 is good from ISO 100-800. I expect this one. K-5 advantage clearly shows at 1600 and above. personally the K-5 is very good until 6400. past that it's downhill.

anyway, the K-7 shows some significant noises from ISO400 and IS0800 with underexposed images. I would believe the K-5 has no issue with this. for someone who needs an exposure of 1600 ISO, I would believe that taking advantage of the K-5's DR would be better and pushing the exposure from base iso.

Last edited by Pentaxor; 12-20-2010 at 10:33 PM.
12-20-2010, 10:04 PM   #30
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Appreciate your testing! As just an old Squirrel shooter, I don't understand most of the tech talk, but I understand photos and the higher ISO advantage of the K5 is obvious to my eyes. When shooting Squirrels, and such, in shaded scenes with dark shadows, the K5 should boost my abilities over my current K20D considerably...although I will have to say that the K20D has been a trusty and excellent workhorse the last two years for me. I don't see how the K5 can surpass its dependability, that would be amazing!
Best Regards & Thanks again!
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