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07-14-2013, 02:11 PM   #1
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K30 JPEG Engine

The jpeg engine in K30 seems different from the rest of the gang (K5, Kx, etc.) The ability to recover from the shadow seems limited. Look at the shadow area recovered from the images from the K-30 review page for "Dynamic Range Test: Original JPEGs" (compared with K5)

(recovered from K30_-3EV)

(recovered from K5_-3EV)

(recovered from K30_-5EV)

(recovered from K5_-5EV)


One could see from -3EV cropped images, colors of wall and leaves have already lost in K30 while still preserved in K5. In -5 EV cropped images, colors of tree trunk, wall and leaves in darkness are completely disappeared. K5, on the other hand, still preserves the color of trunk and the degree of loss in the color of wall and leaves is relatively less. I have done similar tests on Kx vs K30 and find similar results.

Since the shadow recovery from RAW images is comparable between K30 and K5, it is indicated that the sensor performance is similar between the two. The jpeg process engine in K30, however, is far different from the rest of the gang. I wish this issue could be addressed in the updated firmware for K30.


Last edited by lanx0003; 07-14-2013 at 09:40 PM.
07-14-2013, 02:33 PM   #2
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I don't think this can be considered an "issue", as the k30 has a newer cpu and Pentax probably tweaked things a bit. However, the k30s DR is of course not quite as good due to the 12 bit raw.

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07-14-2013, 02:47 PM   #3
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QuoteOriginally posted by Adam Quote
I don't think this can be considered an "issue", as the k30 has a newer cpu and Pentax probably tweaked things a bit. However, the k30s DR is of course not quite as good due to the 12 bit raw.
Adam, like I mentioned in the post, the RAW from K30 is still able to preserve the details in darkness. Although it is relatively inferior to 14-bit raw but not quite far different (look at the raw images of -5 EV). I strongly believe it is an issue of the jpeg process engine. What I mean by an "issue" is that it will be an unpleasant experience seeing those ugly spots recovered from shawdow/darkness for the K30 users. Apparently, the "issue" in my Kx and the K5 here is much less.

In addition, K01 is also in 12 bit raw but I have not found similar issue.

Last edited by lanx0003; 07-14-2013 at 06:12 PM.
07-14-2013, 03:09 PM   #4
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lanx0003, what JPEG settings did you use (such as Bright, Natural, etc.)?

07-14-2013, 04:23 PM   #5
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QuoteOriginally posted by IchabodCrane Quote
lanx0003, what JPEG settings did you use (such as Bright, Natural, etc.)?
In the Kx vs K30 test I have performed myself, I was using Natural mode with "contrast" adjusted down by 1-2 notches from the middle, "In/Low key" 1-4 notches down from the middle to offset the negative effects. Similar to the "DR range" correction, the In/Low key adjustment upward would only make the recovery more difficult.

For the attached images excerpted from the K30 in-depth review, Information regarding the picture style used in the was not revealed.

Last edited by lanx0003; 07-14-2013 at 09:37 PM.
07-14-2013, 06:59 PM   #6
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Seems as though several independent reviews have found the K-30 lacks in the .jpeg engine department vs. both the K-5 series and even the K-01. It does seem that the mode chosen is a key factor. The default "Bright" mode is pretty much designed for the teen camera-phone eye-candy crowd, Pentax is being a bit foolish to expect that the usual reviewers (present company excepted) are going to know that the more serious users (if not sticking with RAW in the first place) are going to use the Natural, Portrait or Landscape modes yielding not only far-wider DR, but more realistic results.
07-14-2013, 08:12 PM   #7
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QuoteOriginally posted by ScooterMaxi Jim Quote
Seems as though several independent reviews have found the K-30 lacks in the .jpeg engine department vs. both the K-5 series and even the K-01. It does seem that the mode chosen is a key factor. The default "Bright" mode is pretty much designed for the teen camera-phone eye-candy crowd, Pentax is being a bit foolish to expect that the usual reviewers (present company excepted) are going to know that the more serious users (if not sticking with RAW in the first place) are going to use the Natural, Portrait or Landscape modes yielding not only far-wider DR, but more realistic results.
I am glad more and more users understand the rationale and purpose of using the mode/style such as Natural that the jpeg engine exerts less enhancement/processing on the image elements. Just like you have mentioned, if not using raw, those modes preserve more information in jpeg and allow users to perform due post processing to achieve higher DR images. Sometimes, I even adjust the saturation level down to reduce the color clip.

On a separate note, no offense but I think K30 does not deserve a perfect score 10 for its image quality as rated in the in-depth review of this forum, at least not for its jpeg engine. In my humble opinion, a camera deserving such a high remark should have superior performance in both raw and jpeg formats. It sounds silly and a design defect to me if the reason that a regular user is forced to shoot raw is to avoid the lousy jpeg output like that.
07-14-2013, 10:34 PM   #8
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No doubt, the reviews of the K-30 have been a bit more glowing than warranted in some instances. I'm disappointed in several aspects of the K-30, and I recognize that the K-5 (and its newer versions) deserve to be considered flagship for the majority of users.

My use is particular in that I don't do much in the way of things the K-5 clearly does better - i.e.: action shooting fps (but probably a bit less accurate AF); most of my better optics are MF legacy (K-30 superior LV and FP); I rarely shoot jpeg - and certainly never when it counts: and I have become familiar with the K-01 protocol (very dissimilar to the K-5). I know that the K-5 is 14-bit, but from a practical standpoint regarding shadow detail it amounts to spit in a pond when comparing to 12-bit. So, from my viewpoint, I want the better MF performance (K-30), RAW is essentially a draw; the high-speed frame rate isn't a factor for me (AF accuracy much preferred); and I can crow all I want that my Q has an exotic metal body for leisure shooting - but, really, who cares because the image is what really counts (and plastic bodies are easier on your hands in winter cold). Bottom line, I know that I will have great overall success with the somewhat flawed K-30 - serving my needs better than any other Pentax body despite its limitations. And for situations when I need better battery performance, a quieter shutter, more stealthiness, time exposures on a tripod, and decent video and audio (well, only passable audio actually), I have the K-01 - which matches or exceeds the other Pentax bodies in some areas where the K-30 is slightly deficient.

07-15-2013, 07:01 AM   #9
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I'm with lanx on this one. It is my K-30 that he performed the testing with and the transition from jpeg to RAW eliminates the issue. AND it is an issue for me because I have typically shot exclusively in jpeg in the past with my K100, K200.

The jpeg processing engine in the K-30 leaves a lot of headroom for the RAW to improve the images, and I understand the reasons for that, but this massive loss of recoverable color in the shadow areas is unnecessary inexcusable IMHO. The K-30 could otherwise be a stellar performer in jpeg capture mode. The high level of textural detail preserved is testiment that this is not a DR problem, but seemingly a jpeg color processing algorithm shortcoming. I know Pentax can do much better than this as my K200 has jpeg proccessing that leaves relatively little room for improvement in RAW - and I LIKE that. I can pull more detail from the K200 RAW images, but seldom need to because the jpegs are pretty good right out of the camera - which cuts my storage and PP requirements, a savings of both time and money.

For the record, I have updated from firmware 1.00 to 1.04 and the results are the same. If Pentax would address this jpeg shortcoming in the next K-30 firmware release I would be the happiest Pentaxian EVAR!!

Last edited by TourDeForce; 07-15-2013 at 07:26 AM.
07-15-2013, 10:55 AM   #10
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I know the K100D won praise for its JPG output but I couldn't stand it, I used RAW all the time once I'd seen how superior it was on 90% of shots. Because of this experience, I never had much hope for the K-30's JPG output and went straight to RAW. Personally I would rate K-30 JPGs as better than the K100D's as long as they aren't edited.

I agree where the K-30 JPGs lack is in the colour department but it may be a noise reduction issue (I haven't tested this) as there's a lot of heavy colour noise reduction processing that takes place in cameras these days, more so than luminance NR.
07-16-2013, 05:43 PM   #11
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Does anyone know how to report this issue directly to the Pentax design engineer (instead of customer/technical service), so they could clarify or address the issue for K-30 users?
07-16-2013, 06:23 PM   #12
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I remember seeing these images and a thread similar to this over a year ago... what is going on??
07-16-2013, 07:20 PM   #13
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If this issue has already discovered one year ago, i.e, two months after the camera being release on May 21, 2012, it means there are concerns from the beginning BUT the issue has apparently never been clarified or resolved after a year. I wonder if Pentax engineer were even aware of it.

Again, does anyone know how to report this issue to Pentax?! Thank you.

Last edited by lanx0003; 07-16-2013 at 07:30 PM.
10-07-2013, 09:54 AM   #14
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Bright does some very strange color shifts for me. Some blue shades are completely shifted to a neon like blue, same with some magenta colors. Both are very difficult to fix in PP. I guess shooting in natural is the way to go.
10-07-2013, 11:02 AM   #15
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Or, if you are going to do PP anyhow .... shoot in RAW or RAW+. Tweak your white balance and exposure (pretty easy to do with RAW), add enough vibrance and saturation to bring you to the Bright setting you really want. Seconds later...Done.
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