Web Analytics RiceHigh's Pentax Blog: May 2008

Sunday, May 25, 2008

K20D Hot Pixels Issue Verified at Steves Digicams

Normally, I rarely read reviews at Steves Digicams, owing to the non-professional and non-scientific / laymen nature of their reviews in which comments are often made too brief and subjective. However, a DPR forum user today has just pointed out that he found "awful lot of hot pixels" in the latest K20D review at the site. And as pointed out by the first few replies in the thread, I've visited the sample page of the review:-


If you look at those "studio" pictures, it is not difficult to see there are various obvious green hot pixels across the frame which could appear or disappear from picture to picture. The most worrisome thing is that those hot pixels could even appear just at ISO 100 and with in-camera jpegs. Just see these two samples:-



Furthermore, I think the hot pixels are not generated as a function of (longer) exposure time (which should be normal then) as the second picture was taken with flash at 1/45th second. If we are to going to examine the photos in the gallery one by one, it can be seen that even a higher shutter speed could still give (even more) hot pixels.

Despite Steve does not mention about the hot pixels issue in his review (for either he was unaware of the issue or he opted not to mention it), his sample pictures say it all for the issue.

All in all, this is the third review sites who tested the K20D have found or shown the hot pixels, regardless if they reported that or not, or if they have published their reviews or not. Up till now, the Polish site got 3 K20D production units and found all of them had this issue whereas Dpreview had got two production units and found both of them were the same (so that they opted to delay the K20D review instead of telling their readers formally in a published review about their solid findings). Now, Steve's direct out of the camera sample photos show the same. I think now that the issue has now been proven to be 100% real. Let's wait and see what Pentax/Samsung will do to address this problem.

Since that hot pixels issued first surfaced, I have seen that some people said that the hot pixels will not affect image quality. But I am totally disagreed with this. The main reason to use a higher pixel count DSLR is to get more room for cropping. With such hot pixels issue, how can those K20D users to "freely" crop their pictures? Do they need to shoot RAW all the time and use software to remove all those hot pixels afterwards?

Wednesday, May 14, 2008

My Idea of a K1000D

Having seen the ultra success of the ASUS Eee PC (or called the EPC), this let me think about smart marketing decision is always the key way to success for a company.

Even for a weaker company like Pentax, which is actually always lagging behind in the competition, should and could think more about how to determine and create a new marketing segment by making new innovative product which is not present in the current market. The key element to success here is simply product idea but not technology advantages.

So, let's look at the EPC again, it does have smart marketing idea, slogan and promotion by ASUS. It it told that it is Easy to Learn, Easy to Work and Easy to Play (which the 3 Es represent and what its name is formed) but actually it is also very easy to carry with the clear fact that it is very portable and most importantly it is sold very cheap.

The ultra portability and the lowest price tag plus its high practicality for suiting for quite a number of basic daily applications including multi-media ones such as common compressed format movie playback and photo viewing, etc. Despite that the technical specifications of the EPC is not particularly strong, its bundle of advantages have almost overcome all its shortcomings and the lack of high performance by today's standards for sub-notes. It has more innovative unique feature, too, i.e., its static flash memory "hard-drive" which has the advantage of fast read/write speed and lowest possible power consumption to save battery juice and extend operation time.

Well, let's look at the past "recent" successful products of Pentax then. First, we can look at the K10D. The K10D is taking the approach of the more is better in which Pentax gave us many features in a package and on paper we could get a lot in a moderately priced body. However, I don't buy the idea of this as I never think that the K10D is a camera that has the real performance inside, when it is compared the nearly priced products in the competition of the same period. IMHO I must say it is just a re-packaged *ist D which has nearly the same old performance and technologies inside, e.g., the AF and metering parts. In 2003, such low performance and inaccuracy could still be tolerated to a certain extent, but in 2007 I think Pentax should really do much more if they really wished to market the K10D as a mid-level product as it was promoted and priced.

However, I don't think the K10D is a true success for Pentax actually, despite it suddenly gained attentions and some more sales. It is just because quite a lot of the attracted buyers / new users did not find it to be satisfactory as reported quite widely for its sub-par field performance and reliability, nor, there is anything in the Pentax land for those unsatisfied buyers to upgrade. So, Pentax simply could not retain those new customers and the new user base afterall, as those people switched and went away. The worst effect is that it left a really bad impression to them (and other non-users as well, for what it was told by those users) after they switched.

So, let's look back to the earlier previous Pentax successful model then. I think it is the MZ-5 in 1995, which was a true success IMO. The MZ-5 actually had saved Pentax from being dismissed from the SLR market in the mid-90s after the prolonged market loss since the SF series to the Z-series of Pentax SLRs from late 80s to mid-90s. I think the MZ-5 shares very much the successful elements of the EPC. It is very simple to use, not expensive to buy and has all the most basic functions and features but not yet too outdated. It is very clear that the MZ-5 has none of the leading edge technologies which the market leaders had, nor it could compete with any of the Canon and Nikon mid-range counterparts in its era as long as highest system performance aspects were concerned. But why so many people still choose about the MZ-5, including those new comers? .. which eventually suddenly saved the sales of Pentax SLRs and lenses. Just think about it.. It should be noted that the MZ legend lived for many years, until the *ist D came.

If we are to look at another very old truly successful story of Pentax SLR body, it should then be the K-1000 film SLR, I must say. It is of crude specs but it did sell well and for years - nearly two decades! Again, it is just because it is simple and basic *and* sold at a low price. For decades, the K-1000 has been a very good camera for beginners who had limited budgets on *both* body and lenses. The K-1000 can use any of the damn cheap but widely available old original Pentax and 3rd party K-mount lenses in huge number. Owing to its great simplicity, the K-1000 is also ideal for those who like to learn the basics of photography and exposure / metering control (just because it has nothing automatic and the users needed to do all by themselves). Finally, the K-1000 does have a rigid construction and is mechanically very reliable despite its low cost. It does even work and can take pictures without any battery installed.

After all the talks above, I think NOW it's time for Pentax to think about and introduce a K1000D in order to help themselves in getting back some market shares and to get a new beginner customer/user base which can help the company to survive/grow, too. In fact, I bet the K200D and the K20D in fact won't help Pentax much, as both offers are not attractive enough as they are easily replaced by Canon's and Nikon's similar or better offers near the same price that most of the new buyers will choose. Even assuming that the new Pentax products are the same in performance and price, why people would choose a small name instead of the big names (of the big boys)? As for the old K100D and K10D users, I really can't think out a reason why the existing users have any good reason and strong initiatives to "upgrade" to a K200D or K20D respectively.

I think Pentax has been running and heading a wrong way for years since the digital era for their DSLRs. I can bet they could never compete with Canon and Nikon etc. for keeping up the latest technologies in R&D nor they have comparable R&D budget nor they have the same production capabilities as other big boys. So, what they needed to do is to re-introduce a basic, simple and cheap DSLR which is highly preferable to be a small, compact and lightweight one which can be easily carried everywhere (like the EPC). Again, this camera must be very cheap (than ever) and this would attract many beginners who like to try and learn DSLR photography. To make it cheap, it must be very simple in features and specs. And, only to have simple features and specs, the cost of the new DSLR can be lower significantly - just a chicken and egg problem afterall. Of course, to trim down the unnecessary features is the proper way to cut cost, but not to scarify reliability and accuracy.

Nevertheless, even it is made basic, small and cheap, it must have some unique feature(s). I think Pentax had discarded a very valuable thing of theirs since the *ist D, it is the old K lens user and owner base, since they decided to cripple the new body K-mount forever (it is true up till now, at least). By summarising all the above criteria, I think a K1000D has an outlined specs below should sell very well and can attract many new comers:-

1. Weight less than 500g, preferably close to 400g. Size should be smallest or at least it should not be larger than a D60 and a 450D;

2. Keep the full K-mount specifications and compatibility and let the user to use the aperture ring of the K lenses to meter and expose too. I believe that it will be more accurate than the current Pentax digital lens design for the exposure control - the mechanical f-stop positions are individually calibrated, mechanically, for each aperture ring when each K-mount lens was designed whereas the body driven digital lenses' automatic aperture mechanical coupling is just totally outdated and it could just introduce more exposure inaccuracy and errors.

With the re-introduction of the full K-mount, it is possible for Pentax to make a retro-designed DSLR that will surely look cool and unique in the market, like the MZ-5, but just an updated digital version, say. However, since DA lenses are now not having an aperture ring, Pentax can provide a mean for Av selection in electronic form just in case if a DA lens is mounted. On all other cases, the aperture ring should be enabled whenever it is existent on the lens mounted, including the latest DFA digital macro lenses;

3. Keep only Spot and Centre-weighted average metering to save cost and make the camera simpler. The current 16-segment multi-pattern metering is not needed for those who really want to learn the basics nor it is really much useful owing to its low IQ, poor reliability and low consistency;

4. Keep only the AI predictive Single AF mode which is the only AF mode of the MZ-5 (no Pentax DSLR has been told to have any predictive AF capability now - I just puzzle why). I think only one single crossed AF sensor in the middle is more than enough for such a camera. The crossed sensor is preferably to make with higher pixel density, calibrated more precisely but in a smaller area in the finder for pinpointing focusing so that the highest possible AF accuracy and reliability can be attained. I also suggest that Pentax could make a f/5.6 sensor for the horizontal line and a f/2.8 sensor for the vertical line so as to further enhance the AF accuracy. Furthermore, by concentrating in building only the central sensor, the AF system should be re-built to have better overall responsiveness and good sensitivity in low light;

5. To re-build a focusing screen with more visible matte texture, so as to facilitate better Manual Focusing. Also, the plain very old Minolta/Pentax/Nikon focus indication system should be added to indicate front or back focus - well, just a pair of triangles indication in the finder (to indicate the focusing ring turning directions) is required -> nearly no additional cost to re-introduce but a very useful and unique feature nowadays as all camera makers followed what Canon did with their EOS to delete such useful focus indication;

6. It should support both the old Pentax TTL Auto and newer P-TTL flash guns for the unique compatibility again, so as to attract more old users (or even new ones who just want to get used gear cheap and easily). The K1000D can remove the built-in flash in order to further minimise its size and save weight (and manufacturing cost as well - but not to cut the TTL sensor to save the cost but scarify much compatibility - it is not that expensive to include such a TTL flash sensor afterall);

7. Of course the megapixel should be at least 10MP by today minimum standard. The K10D Sony CCD sensor, which is damn cheap right now, can be used;

8. Only P, A, S and M modes are needed;

9. No other bells and whistles are needed then and of course no Live View. I think even different picture modes/styles are not needed, as these could be included in the RAW convertor instead. I think the "Natural" mode is what most users need if the best colour accuracy is desired;

10. Aggressively priced under (US)$400 for such a greatly simplified design.

Having said that such a K1000D may help Pentax, Pentax should still try to make a true flagship later on which it has the real performance for major camera performance aspects. This would let Pentax to upkeep their outdated technologies in line with the latest in the competition. This flagship is preferably to be a 135 Full Frame DSLR, too, which is just the current trend for flagship DSLRs (at least Canon, Nikon and Sony have been or are now doing the same). The flagship serves as a symbol for marketing as well as practically an ultimate upgrade destination for the current Pentax DSLR users - but then this flagship can be made at a later stage after the success of such a K1000D (if it can be, but I do believe it can) and gaining of a considerably number of new users whom probably are mostly students, beginners as well as those very old Pentax users who just want to have ultimate simplicity and portability (and full compatibility as well). By then, Pentax would have more money and bucks to put back for doing better R&D jobs. All in all, I don't think Pentax is really wise to drop the compatibility and support for many of their older excellent lenses and flashes, which those compatibilities are just the true valuable asset of Pentax and compatibility is actually the true product feature differentiator for Pentax, especially for the full and true K-mount support! (40 millions of EOS lenses have now been produced since 1987, as Canon announced. How many Pentax AF lenses have been made up till now (since 1987 also)? If not all the K-mount lenses are counted, how could Pentax compete?)

Monday, May 12, 2008

K20D Banding Problem Reported at Low ISO Speed (ISO 200)

A K20D user has just reported a "banding bug" of his K20D and posted a sample picture made by him which shows serious horizontal banding, at the DPR forum:-


Quoted:- "Each 1 of approx 50 images, taken with k20D, show very specific banding. I can't locate any regularities in there appearence. Other images are absolutely OK. The effect is visible even on the camera's screen."

And here is the direct link of his posted sample banding picture:-


Horizontal bandings are obvious in the whole image, especially at where near the pistils of the flowers which are having more textural details. I have examined the EXIF and it is discovered that the picture was actually taken at a low ISO speed of 200, plus a short exposure time of 1/200th of a second only, which is indeed the most worrisome thing afterall. Moreover, the exposure compensation was set to be -0.3 EV, which means that there should not be any underexposure and then push processing to exaggerate any potential artifact (if any), but the reverse is true, in contrast.

In fact, previously there have been a number of K20D user reports of banding found in pictures made at high ISO speeds and/or with long time exposure. But this time, it is the first time I have heard about banding could occur at such a low ISO speed, which is just an uncommon thing for most (or maybe all) DSLR models ever made and marketed.

I hope this case is just an isolated one rather than a common quality/manufacturing issue or even a design flaw or bug. Otherwise, it will be really a serious issue. Nonetheless, time will tell, when more and more users will report later if there is a real problem. Possibly and hopefully, we shall know about the truth within a few months' time to come.

Sunday, May 11, 2008

K10D Firmware 1.3 Debug Mode Unleashed

According to the following recent DPR post:-

K10D - GX10 1.30 Firmware Debug menu via usb activation.: Pentax SLR Talk Forum: Digital Photography Review

The poster found a program made by someone called "makc" on the "penta-club.ru" forum.

It is told that the program allows the K10D user to access the debug menu with the firmware version 1.30 installed in their cameras (it is believed that it works for the Samsung GX-10 too). With that utility program, the debug mode can be activated and de-activated via an USB cable and no firmware version downgrade is required.

It is in fact very useful and handy for those K10D users who wish to make their own AF adjustment for any Front Focusing (FF) or Back Focusing (BF) found with any of their lenses on their K10Ds. Indeed, the problem of FF and BF of the K10D has been widely reported and especially different amount of focus inaccuracy (no matter it is FF or BF) would occur with different lenses mounted.

Some people also told that adjustment settings up to four (Pentax?) could be made and stored and those settings would be called automatically upon mounting of a particular lens. If it is really true, it is just a very useful feature to counteract the K10D focus inaccuracy abnormality.

The poster has also compiled a tutorial on a French forum to teach people how to use the Russian program above. The link is as follows: Pentax K10D - K20D - bon anniversaire Julien (Registration and member login is required)

Finally, here is the download link for the program: http://dednev.pisem.net/setup_gx10_dmctrl_1.1.exe
The password for installation is : penta-club.ru

Good luck but bear in mind that YMMV, though. If you do not have the total confidence and cannot bear any potential risk involved, just don't try - my humble advice.

It should be also noted that it has been reported that the program is not Vista compatible. With Vista, the debug mode can be activated but not de-activated. See this post for more details.

Update (25/6):

Here is the good news! The original Russian author of the program, "makc", has just released a new version of the utility in English language. The download link is as below:-

( Password: penta-club.ru )

Happy measurbating and adjusting!

Friday, May 09, 2008

Issue of Hot/Dead Pixels of the K20D

Reports of the hot/dead pixels found in images produced by different K20D units continue and lately it has been reported by a DPR technical writer, who is responsible to review the K20D:-


"During testing we have encountered the same problems with hot pixels that have been reported elsewhere. We have continued to experience the same difficulties with a second production body and are currently awaiting a response from Pentax before proceeding with further testing."

So, where's the "elsewhere" as mentioned? Here it is:-


Since the above review is in Polish, someone had summarised some of the key points and posted it below:-

K20D not recommended, inconsistent hot pixels issue

And, some of the key statements are quoted:-

"main issue was inconsistent quality between K20D samples, which they consider to be 'unusual development for Pentax products, and sad to see '. They tried a few different K20Ds, all had hot pixels, but was was particularly worrying was that hot pixels changed in each sessions, disappearing and appearing in different places. This appears to indicate production issues with the latest 14.6 megapixels sensor (made by Samsung)."

"See the above URL and go to section 7 for samples of noise and hot pixels. The site also found that there are many hot pixels (more than in other equipment they tested), and that the hot pixels are permanently mapped and excluded in JPEGs during in camera processing, thus there is more and more excluded hot pixels due to their unpredictable and changing appearance. It was unclear is there a way of resetting this mapping, but this would be fixable (if Pentax decides to do so) in future firmware."

For those who has limited bandwidth in accessing the Internet, a direct link of a sample picture showing many random hot pixels is here:-


"The test had many other criticisms and discovered inconsistent quality issues. The very first K20D they purchased produced loud focusing noises, exposed badly, and was assembled badly -- it was replaced by a local distributor, and many issues were not present in the replacement... but some came back in the third K20D they tested."

Well, is there any report from real K20D end-users (not reviewers) for the hot pixel issue then? Yes, I've seen two new K20D reported about the hot pixels found in pictures produced by their K20D in a thread opened one month ago:-


(Post in Traditional Chinese, use BabelFish is required)

Direct link to a sample "hot" picture can be seen here.

The thread open person also reported that he had tried the K20D "pixel re-mapping" function, which is essentially a method to rule out known hot or dead pixel(s) by disabling particular pixel with problem and instructing the camera to use the neighbourhood pixel values to calculate (aka interpolate) a new value to insert into that dead pixel. However, he wrote that the problem could not be resolved even using this available function. So, finally, as the local Pentax service centre was unable to resolve the problem, they sent his unit back to Pentax Japan. The user has finally got back his K20D unit and he has made a quick post in telling us that the problem "has been resolved", with a small downsized sample picture posted too. But however, I am not sure if he has thoroughly tested his unit or not as he has not reported back further in details since then, despite he promised that there would be a more detailed "final" report ...

Afterall, it seems to me that it is just a hardware bug of the Samsung new CMOS sensor (for which Pentax was naive enough to hope that the firmware could eliminate the problem all). It might be that the pixel density are just too high as too many pixels are packed in a too small area with a too large photo site per pixel and with too little isolation/separation between pixels too such that the whole sensor/image may become just too hot for the inside temperature when it is working. As such, the accumulated thermal energy, which possibly could not be drained away properly physically, has caused electrical signal noise got out of control somehow at certain areas and finally those physically heated up pixels are recorded in the final image as hot pixels or even dead ones (if it constantly appeared red or green, usually).

Thursday, May 01, 2008

Pentax Starts to Drop Support for Body Driven AF

In the following specifications table of the new DA 17-70/F4 SDM found in the Pentax Norway website:-


It is stated that "Autofocus only functions if the mounted lens features a supersonic motor (the camera motor will not drive autofocus)."

Putting aside the logical mistake for the first part of the statement (how comes in the specs of a SDM lens to state about "if the mounted lens features a supersonic motor"?), I think what it really wants to tell is for the message in the brackets, that is, "the camera motor will not drive autofocus (with the DA 17-70 lens), which is simply meant that when the DA 17-70 is mounted on any older Pentax DSLR bodies prior to the K10D, it will have no AF function as none of those older bodies could support any SDM lenses. For AF to work, it must be used on one of the following four latest Pentax DSLR bodies: either a K10D, K100D Super, K20D or a K200D.

So, if Pentax starts to drop support for body driven AF in their latest lens, what does this imply? It simply hints that in the future it is possible to see new Pentax DSLR bodies which do not have body AF motor at all (like the Nikon D40/40X etc.) or more new Pentax AF lenses that are yet lens motor driven alone for the AF and it is also possible that eventually Pentax will completely discard their older body AF system.

No matter any or all of the above three possible cases happen later, it just means less backward and/or forward compatibility between different generations of lenses and bodies.

Nonetheless, without the burden of compatibility, that "pure" SDM design *may* have better AF performance (faster and/or more accurate, hopefully) and that another thing is for sure - it is simpler in design and is surely cheaper to make, no matter for the lens or even for the body - which only lens driven AF is included.