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06-25-2008, 10:50 AM   #1
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K20D Highly recommended on DPR

Pentax K20D Review: 1. Introduction:

Rating (out of 10)
Build quality 9.0
Ergonomics & handling 8.5
Features 9.5
Image quality 8.5
Performance (speed) 8.0
Value 9.0

Highly Recommended

06-25-2008, 10:57 AM   #2
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Beat ya to it!
06-25-2008, 03:45 PM   #3
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makes me want to go out and buy one now!
06-25-2008, 05:43 PM   #4
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QuoteOriginally posted by PFH Quote
Pentax K20D Review: 1. Introduction:

Rating (out of 10)
Build quality 9.0
Ergonomics & handling 8.5
Features 9.5
Image quality 8.5
Performance (speed) 8.0
Value 9.0

Highly Recommended
Great + Good + "push"
Well in my opinion:

1) Noise level at high ISO performance is resonably acceptable (trade off for higher pixel + resolution + retain more details). But still need to work hard on improvement in this area!!
(I saw 450D at high ISO and its sharpness but if you look at the reflection from glass bottle etc, it was too digital to me!!)

2) include focus adjustment for different lenses: Solved the root cause of "combined Uncertainty/ Errors" of optic (due to alignment). Besides, this solution is cheaper than "intensive calibration/fine-tune" on the production lines. Focus correction is feature "trended" as demanded by many customers. Please devolve this feature to all the K series.

Keep on!!!... technically catch up + Voice of customer + improvement


Last edited by ckanthon; 06-25-2008 at 06:46 PM. Reason: paragraphing
06-26-2008, 06:01 AM   #5
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K20d has been described by Taiwan P-Fans as the "Darker of Darkness"
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Last edited by ckanthon; 06-26-2008 at 06:07 AM.
06-26-2008, 06:16 AM   #6
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I see that the K20D has perhaps the best dynamic range of the bunch. I purposely under-expose my pictures by 0.5 of a stop so I can have more highlight headroom. To me, good shadow detail is a must.
06-26-2008, 06:38 AM   #7
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QuoteOriginally posted by ftpaddict Quote
I see that the K20D has perhaps the best dynamic range of the bunch. I purposely under-expose my pictures by 0.5 of a stop so I can have more highlight headroom. To me, good shadow detail is a must.
So do I..

Ben
06-26-2008, 07:48 AM   #8
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"Dark"? Yes! ;-)

QuoteOriginally posted by ckanthon Quote
K20d has been described by Taiwan P-Fans as the "Darker of Darkness"
Yes, but provided that the exposure is accurate and correct at the first place, which is unlikely, according to the sample photos posted at the DPR K20D gallery:-

RiceHigh's Pentax Blog: K20D Exposure Inaccuracy and Inconsistency

Nonetheless, according to another K20D measurement test, the DR is not really good (and actually worse than the K10D, if exposed for highlights rule follows), see: RiceHigh's Pentax Blog: Dynamic Range and (Background) Noise Tests of the K20D

06-26-2008, 07:52 AM   #9
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RH I usually do read through some of your info as it presents a good "other side" comparison to help judge Pentax products on but this DR issue you are just plain wrong on

I'm pretty sure dpreview did a pretty extensive testing and review on this camera even moreso than others considering how long they've had it and needing to basically test it twice.

Though two blog post you put out have no controlled test actually done by yourself... that is pretty weak.
06-26-2008, 08:00 AM   #10
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Uncontrolled tests??

QuoteOriginally posted by Okami Quote
Though two blog post you put out have no controlled test actually done by yourself... that is pretty weak.
Not really. Please read again. Both the DPR K20 and D300 sample galleries are done recently, in England, for similar scenes, and by the same DPR team.

As for the DR test, the same authors did the DR test and background noise test with the same test setup and methodology.

I have nothing to do with those tests, I just quote them or make some quick and simple statistical analysis. For anyone who is interested, just figure out yourself and I think you will judge.
06-26-2008, 08:08 AM   #11
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If you don't consider their testing well done, then why do you quote other people?

Where are the test done by yourself? I don't see how you can judge other people's test without a testing system that you yourself uses and presents to people.

That really doesn't make sense

Anyone can nitpick on anything. It's you putting your own ideas into action and for other people to judge that will really give you credibility
06-26-2008, 08:27 AM   #12
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QuoteOriginally posted by RiceHigh Quote
Yes, but provided that the exposure is accurate and correct at the first place, which is unlikely, according to the sample photos posted at the DPR K20D gallery:-

RiceHigh's Pentax Blog: K20D Exposure Inaccuracy and Inconsistency

Nonetheless, according to another K20D measurement test, the DR is not really good (and actually worse than the K10D, if exposed for highlights rule follows), see: RiceHigh's Pentax Blog: Dynamic Range and (Background) Noise Tests of the K20D
Hi rice,

Thanks for your valuable advices. I wished I could have both K20d and K200d in hand and could perform some field tests which could be quite wonderful. Unfortunately, my baby went to hospital, therefore, there is no reason for me to take shoots!!. You see, a typoon came again after twices weeks of long and heavy rain in Hong Kong.

In my opinion, K200d's pictures really buried some details in "low" light part but actually I did not know how to extract them out. MS photo manager seemed worked for certain situations. (Good news cause' I don't need to consider buying a package of photoshop at this moment.

You know, something bothered those P-fans in HK after reading below contents on the DPview report:
Long Exposure noise reduction / Night shots
Somewhat unhelpfully, the K20D does not allow you to turn off long exposure noise reduction (normally the subtraction of any positive data that appears in a second exposure taken with the shutter closed).


They asked if this meant "it is hard to take pictures for fire-work". I did not find such texts inside the review yet (no time yet) but quote them out.

How do you think of this issue?
06-26-2008, 06:09 PM   #13
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QuoteOriginally posted by PFH Quote
Pentax K20D Review: 1. Introduction:
[...]
Highly Recommended
Let me come back to the review.

I found it pretty good. It showed a reasonable level of involvement on behalf of the testers. It was a good piece of work, as well. Possibly the best online review written to date on the K20D.

Therefore:

Everybody please vote (in this thread):
  1. dpreview reviews shall no longer be regarded biased towards Canikon
  2. a single balanced review isn't significant (yet).
  3. I'm wrong, the review wasn't fair, one more time.

My vote: 1.
06-26-2008, 07:49 PM   #14
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QuoteOriginally posted by RiceHigh Quote
Yes, but provided that the exposure is accurate and correct at the first place, which is unlikely, according to the sample photos posted at the DPR K20D gallery:-

RiceHigh's Pentax Blog: K20D Exposure Inaccuracy and Inconsistency

Nonetheless, according to another K20D measurement test, the DR is not really good (and actually worse than the K10D, if exposed for highlights rule follows), see: RiceHigh's Pentax Blog: Dynamic Range and (Background) Noise Tests of the K20D
Dang you are still funny. For years you quote DP Review as the know all be all source of Pentax "criticism". Now that Phil, whom in the past you petty well had glorified as "THE expert" thinks the DR of the k20 is pretty darn good, you have to find another source of "bad data"... Tooo funny.
Phil: Pentax K20D Review: 20. Photographic tests (DR):
Camera (ISO 100)
Shadow range Highlight range Usable range
Pentax K20D -5.8 EV 3.2 EV 9.0 EV
Canon EOS 450D -5.1 EV 3.6 EV 8.7 EV
Sony DSLR-A700 (200) -4.9 EV 3.9 EV 8.8 EV
Olympus E-3 -5.8 EV 3.0 EV 8.8 EV
Pentax K10D -4.5 EV 2.8 EV 7.3 EV
The Pentax K20D: a RAW review, page 3
I would think that this DR limitation will come out when the camera is reviewed by the best of the review sites such as DPReview and Imaging Resource

(Digital Cameras, Digital Camera Reviews - The Imaging Resource!).
Apparently that is not so.... so far. I'm waiting for the imaging resource review.
So who to believe? I'm soo confused

And as to your new found friend, after I learned that ACR may not do a linear exposure correction (as it should) I really don't trust it... can blow highlights when it shouldn't and it can create more noise. As far as I'm concerned ACR has never really been the best converter (only the most used).
Anyway while looking for the ACR "exposure adjustment problem" I found this for you....... it's pretty funny actually:
Luminous Landscape Forum > Zone System, light metering and neutral gray
Oh as to Gordons, Oleg's and if you add john Sheey's data. The general consensus was the K10 had a tested DR that was considerably high (at the time the highest they tested I believe). Unfortunately the VPN made it a bit unuseable.
They did conclude that the k20 was a stop lower than most of the current cameras. Data that is completely contrary to dpreview as far as I can tell.....
Apparently somebodies methods (or sample variation, or minor assembly line revisions) is at fault.
BEST thing Trust your eyes... DR of all these cameras, in reality and practice, is probably close to equal....
Good technique, and a good RAW converter, will outweigh good theoretical stats and day. At least w/ DSLR's...
Pentax K10D daylight image noise test [Archive] - Aussie Phorums
From what I gather from people who have tested the K10D more objectively,
it is the #1 DSLR for dynamic range at ISO 100, at the pixel level. The
1DSmkII might be close at the image level (dividing noise by the linear,
one-dimensional pixel resolution).

It has no real optimization at higher ISOs, though, like Canons do. Most
cameras don't; they have a single at-photosite read noise, and multiply
it in amplification, and then add the analog noise of the ADC, so the
total read noise as measured in electrons only improves ever so slightly
at higher ISOs, as opposed to dramatically with Canons. For most of
these cameras, the only benefit of higher ISOs is the brightness of the
review image; under-exposing at a lower ISO may provide almost the same
quality, without sacrificing highlight headroom. Quantization is not a
significant issue with these analog noise levels.

The standard deviation of an ISO 100 blackframe from the K10D (according
to my source) is about 0.9 DN/ADU. The Fuji SLRs, the Canon 1D* cameras,
start at about 1.3. Non-1D Canons are at 1.65 to 2.1, and most Nikons
are at about 3.0 or so. Some cameras clip the RAW data at black, and
some don't. These values are normalized to those that don't, as the
noise is only clipped near black in the cameras that do clip at black,
and not at higher luminance levels in any camera (blackframe noise must
be multiplied by about 1.64 for black-clipped RAW images).

With the K10D black noise at only 0.9 DN/ADU there is probably a little
bit of quantization noise, so ISO 200 probably is a bit better than ISO
100 under-exposed (ignoring the stop of highlights), so it has more value
than just a brigher review image or default conversion or JPEG.

The probably reason that the extra DR is not noticed in many DR reviews
is that the images are rendered with normal transfer curves, leaving the
extra shadow ranges down in the dark, where you can't distinguish them.
You really need to boost the shadows to appreciate the difference. There
is also the issue of where the camera exposes the middle grey in the RAW
data; this can vary quite a bit from camera to camera, and converters are
not consistent in the way they utilize RAW highlights.

John P Sheehy

Last edited by jeffkrol; 06-26-2008 at 08:09 PM.
06-26-2008, 09:55 PM   #15
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Re: Dark Frame Subtraction NR always enabled in K20D

I think what they are talking about is that the Dark Frame Subtraction Noise Reduction for longer time exposure which in the K20D does not have the option for the users to turn it off.

In the past, all Pentax DSLRs could have the Dark Frame Subtraction turned off, as a option. It seems that the new Samsung sensor of the K20D is just too noisy that Pentax decided to force it to turn on all the time and thus disable the option.

Do note that the Dark Frame Subtraction "NR" is different from those NR by NeatImage etc. noise removing software (and in-camera NR for high ISO as well) to filter out noise. Here for the Dark Frame Subtraction, what the camera need to do is to take another photo with the same amount of time and then do a subtraction afterwards, pixel by pixel, so as to "remove" hot pixels (actually all picture data in those pixels are removed altogether).

Just say if you shoot fireworks. For a picture taken with 5 seconds. Then, you will need another 5 seconds for the camera to close the shutter and then take another picture and then finally do the calculation (subtraction). So, depending on the amount of processing time required, the total time required to take a picture should be at least 10 seconds or more. My *ist D took a very long time to do the processing where as the processing time for my 5D is neglectible. But anyway, in short, whilst the time for shooting is only 5 seconds, there is at least 5 more seconds to wait, in this case.

Whether this Dark Frame Subtraction NR waiting time cause problem to the user is solely dependent on what the user need, think and want (or don't want). If there is an option to turn it off, time will be saved but hot pixels would appear. Take your example question for shooting fireworks, this would cause problem if you want to shoot non-stop. Otherwise, just wait for a few seconds.

Here is a "recent" example work of mine. Just view the EXIF tags for more info if interested and I hope you like it!



Last but not least, I hope you and your family well. Take care. :-)

QuoteOriginally posted by ckanthon Quote
Hi rice,

Thanks for your valuable advices. I wished I could have both K20d and K200d in hand and could perform some field tests which could be quite wonderful. Unfortunately, my baby went to hospital, therefore, there is no reason for me to take shoots!!. You see, a typoon came again after twices weeks of long and heavy rain in Hong Kong.

In my opinion, K200d's pictures really buried some details in "low" light part but actually I did not know how to extract them out. MS photo manager seemed worked for certain situations. (Good news cause' I don't need to consider buying a package of photoshop at this moment.

You know, something bothered those P-fans in HK after reading below contents on the DPview report:
Long Exposure noise reduction / Night shots
Somewhat unhelpfully, the K20D does not allow you to turn off long exposure noise reduction (normally the subtraction of any positive data that appears in a second exposure taken with the shutter closed).


They asked if this meant "it is hard to take pictures for fire-work". I did not find such texts inside the review yet (no time yet) but quote them out.

How do you think of this issue?

Last edited by RiceHigh; 06-27-2008 at 04:32 AM.
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