Web Analytics RiceHigh's Pentax Blog: May 2007

Friday, May 18, 2007

Is the K10D Really Sluggish in Shutter Lag?

This has been a hot discussion and debate topic for months at various Pentax forums, which is solely about the system and/or AF time lags and the actual performance of the K10D in this important (IMHO) aspect. Here is one of the examples. Some people do have suggested that the time lag is actually just a feel caused by the sound(s) of the K10D generated during a shot (example here), but then actually "feel" is not something we can take reference for, at least not objectively, as different people "feel" things (that can be quite) differently and have (can be very) different "feelings".

Okay, to look into this issue, which is actually not really so mysterious and arguable as it should be, the simple solution is to do measurbation. Once enough measurbations have been carried out and adequate results and data are obtained and compared, we can know about the true answer. Well, now it is when measurbators show their true value for existence this time!

In fact, the answers have already been there! So, further arguments are actually meaningless. Since quite some times ago, the Imaging Resource has routinely measured various shutter and system time lag figures in their Digital SLR test reviews, for 3 or 4 different timings under different usage conditions, namely, "Full Autofocus", "Prefocused", "Continous AF" and "Manual Focus", as called by them.

To know and understand the background for why they have been conducting the tests and how accurate are their test results, here is a quote of the introductory remark in the beginning of the timing test data page of their earlier DSLR test reviews:-
"When you press the shutter release on a camera, there's usually a lag time or delay before the shutter actually fires. This time allows the autofocus and autoexposure mechanisms time to do their work and can amount to a fairly long delay in some situations. Since this important number is rarely reported on (and even more rarely reported accurately), I routinely measure it, using a custom-built test setup. (Crystal-controlled, with a resolution of 0.001 second.)"

Okay, now let's read the performance data page of the latest Imaging Resource Pentax K10D review, we can first have a look at the measured figures and also the corresponding explanations which illustrates the true meanings of those, at the right side column in the table.

Nonetheless, do note that the explanations and remarks in the above K10D review page are, however, not entirely clear and exact. To know exactly, one need to look at some earlier test reviews which the Imaging Resource explains in more details for what they are actually doing. I think they just have assumed that their readers have already understood all those and thus have trimmed down the remarks (but then they might have forgot about there are new readers!).

Well, to make the case clearer, I shall explain once more in my own words and quote the words in certain previous Imaging Resource test reports, wherever appropriate, for the four measured timings of the (can be different) system time lags of a DSLR, as follows:-

1. "Full Autofocus":- The camera is put in the Single AF mode but the target is pre-focused beforehand but the shutter release button is released first. And then the timing is measured "from scratch" by re-pressing the shutter release button for measuring the time required till the exposure finally happens. The following is quoted from (the timing results page of) their earlier Canon EOS 30D review, here it is: "This is basically a measure of how quickly the camera can determine focus, with the lens elements already set to the focal distance of the subject."

The true meaning of this timing figure is to look into the responsiveness of the AF system under the Single AF mode, plus, the *remaining* system time lag of the DSLR. Since the Single AF is focus priority, full AF system operations, from measure the focus, move the AF motor (if any required) and then checking the focus again, are carried out before the shutter can be released. The travelling time of the lens is ignored and it's wise to ignore it as it varies with different lenses and different travelling distances for different objects and etc., as it is also mentioned very clearly about this by Imaging Resource in (the timing results page of) their Canon EOS 5D review, "AF time will vary greatly, depending on the lens in use, the brightness and contrast level of the subject, and the amount of travel required of the lens optics to move to the new focus position. The number at left is essentially a best-case figure with the Canon 100mm f/2.8 macro lens already in-focus on a target.";

2. "Prefocused": - The camera is put into Single AF mode again but the focusing is achieved beforehand with focus held and locked by keeping half-pressed for the shutter release button before the measurement. The true meaning of this measurement is an attempt to ignore about the delay incurred by the AF system and check the *net* system lag time;

3. "Continous AF":- Since in Continuous AF mode, it is not (correct) focus priority, which means that no correct focus will be re-confirmed and re-assured and the shutter release will not be withheld and it can be released at any time. So, whilst the AF are still in operation and continuously, the total system lag time can yet be shorter but it should be longer or just equal to the prefocused one as the AF system is still in operation which might affect the overall system responsiveness;

4. "Manual Focus":- It's self explanatory, the camera is put into MF mode and the system lag time is measured. Still, do note that the focusing system of the camera is not totally inactive as measurement of the in-focus point is being carried out continuously for the provision of focus indication to assist the user to do the MF.

Okay, now that we can go forward to check and compare the measured figures for different DSLRs, for the data results obtained in various Imaging Resource reviews. For the sake of easy reading and quick comparison, I summarise the results in the following table:-

"Full AF"
(Single AF,
Prefocused but Released first)
(Single AF,
Prefocused and Held)
"Continuous AF"
"Manual Focus"
Source Page Link for
the Timing Results
Pentax K10D
0.254 s
0.107 s
0.183 s
0.181 s
Pentax K100D
0.182 s
0.149 s
0.148 s
0.150 s
Pentax *ist D
0.23 s
0.13 s
0.18 s
Canon 30D
0.245 s
0.068 s
0.105 s
0.154 s
Canon 400D
0.20 s
0.105 s
0.12 s
0.13 s
Canon 5D
0.149 s
0.078 s
0.133 s
Canon 1Ds MkII
0.18 s (?)
0.070 s
0.057 s (!)
0.052 s (!)
Nikon D80
0.250 s
0.083 s
0.095 s
0.083 s
Nikon D40
0.26 s
0.098 s
0.20 s
0.19 s
Nikon D200
0.21 s
0.057 s (!)
0.057 s (!)0.057 s (!)Click
Nikon D2Xs
0.045 s (!!!)
0.045 s (!!)0.045 s (!!)0.045 s (!!)Click
Olympus E-500
0.37 / 0.38 (??)
0.095 s
0.43 (??)
0.32 (??)
Sony A100
0.31 (??)
0.116 s
0.301 (??)
Full AF
Continuous AF
Manual Focus
Source Page URL
Remarks: ! = Wow! ? = What?

So, now that you can compare and judge yourself and I won't comment particularly on anything further. Just for a final remark, for people who are always trying to defend for anything and argue about human reaction time is the slowest thing on Earth, I indeed regard this "point" is indeed rather groundless and actually pointless. It is because in fact the machines are made differently as we can all see from the above. There are obviously great to certain degree of differences under the above four shooting conditions. The true fact is that cameras (of different grade) are engineered and built differently, as all camera makers are well known about this fact. BTW, who will really want to add even more time lag on the top of the somehow already slow human reaction time? Nevertheless, the human reaction time is not really that slow as some would believe, especially if the photographer has stood by to take some photos. If still unconvinced, just use a single-button stop-watch, press to start and try your best to press again to stop, then note the time difference, one can then see the (stood-by) human reaction time can still be quite fast (mine is about 0.12 s).

Wednesday, May 16, 2007

Pentax Re-Considers to Accept Takeover by Hoya

Pentax is now re-considering to accept the takeover bid offer by Hoya and probably Pentax will still be merged by Hoya. Two Japanese online news sources tell the same thing on yesterday and today, respectively:-

Kyodo News: http://home.kyodo.co.jp/modules/fstStory/index.php?storyid=314750

The Daily Yomiuri: http://www.yomiuri.co.jp/dy/business/20070516TDY08004.htm

The good thing is that Pentax seems to be able to fight for maybe better terms for the merger for the time being, for what they have been trying to struggle (to get away) in the past months, including the recent announment/reporting of their annual business results, which looks somehow promising.

Okay, let's look at the complete second last paragraph of the Yomiuri report, which is quoted as below:-

"As a condition of accepting the takeover, Pentax is demanding a guarantee of management independence and the removal from the board of directors of former senior managing director Katsuo Mori and former president Fumio Urano, who had spearheaded the merger talks with Hoya." - Daily Yomiuri Online, May 16, 2007.

Well, the first guarantee is a good promise if true (however which can still be breached by the True Authority in the future anyway, if They like). The second thing being demanded for is really interesting and mysterious, i.e., the request of the removal of Urano and Mori. Why they must get rid of Urano and Mori? Why they can't stay even the merger has come true? There must be some insider stories that we don't know and probably shall never know..

While just the day before, on May 14, another news report discloses that a managing director of Pentax tells that there likely will be a "White Knight" who will save the company in time finally and does the salvation. Now it looks rather ironically that the "White Knight" is actually Hoya! Is that real? Time will tell and we shall know.

Last Related Story: Pentax to Sell Tokyo HQs, Quit MF and P&S Businesses

Saturday, May 12, 2007

Klaus Schroiff's K10D Review at PhotoZone

Klaus Schroiff, site owner and editor of the PhotoZone, recently has published his K10D full review and test report:-


I highly recommend to read this report of Klaus's (also for his other reports, without any hesitation) as his findings and conclusions are sensible and insightful, most importantly, comments and conclusions are usually made with good enough technical grounds and evidences. Nevertheless, his report is yet concise and easy to read. Of course, some of his particular conclusions and viewpoints made can still be subjective somehow but then this is of no difference from any other reviewers. At least, his tests and reviews are in a comparatively higher standard class of only few truly quality reviews belong to, amongst all other numerous sub-standard so-so "reviews" floating around the net.

Well, in Klaus's test report, he has actually reported something new, of which these new findings have never been reported by anyone so specifically before.

One of his new findings is about the obvious differences in resolution and the appearance of moires, etc. along the vertical versus the horizontal directions. With this strange and unique behaviour which I have reported here previously, Klaus did consider that it's simply a design flaw when he first saw the symptom. Later on Klaus was able to find out the possible cause to this problem, which is believed to be caused by the unequal strength of the Anti-Aliasing (AA) filter in the vertical and horizontal directions, more specifically: In the vertical direction, the AA filtering is much weaker than normal (i.e., very little dispersion to none, microscopically). And, in the horizontal direction, the AA filtering is yet stronger than typical (i.e., more dispersion).

Well, if we read into the details presented by Klaus. We can see that neither a too weak nor a too strong AA filter is good for the final image quality. Too weak a filter will create colour moires and very visible Bayer artifacts. Too strong a filter will decrease resolution significantly and blur the image too much.

It is found that Pentax takes the approach of using software (no matter it is in-camera or not) to do the demosaic job, as a remedial to the weak AA filter, vertically, which unfortunately just create even more blur and resulting in more loss in resolution. If 3rd party RAW convertors are used to convert the images, it can be seen that more serious and obvious colour moires will appear, although more resolution can be retrieved, also this will generate more noises too (see in the report for the noise level comparison by different convertors).

On the other hand, for the horizontal run, the image quality suffers from another extreme. So, this asymmetrical design of the AA filter, simply cause much undesirable effects which, however, cannot be handled by any RAW convertor with any software algorithm. In the end, one must see either more colour moires with better resolution (about vertically) or an image with less colour moires and noises but with inferior resolution and obvious blur.

The worst thing IMO is that the images will always look somehow different in vertical run against horizontally. I just wonder why Pentax need to design and make a camera in this way, of which this design and the produced results are indeed very strange and the image quality suffers and that no other DSLR makers else have ever done so, nor Pentax themselves for their previous models.

BTW, as we all know, the selling point of a 10MP+ DSLR is its higher resolution, however, the K10D by itself simply fails to deliver, no matter shooting in Jpeg or RAW, if only Pentax software is used. If one uses 3rd party RAW convertors, more moires and noises are resulted. Even worse, do note again that these are not symmetrical vertically and horzontally.

Whilst Klaus finally mentions this strange problem, which was actually first reported by him, is just a "Minor Con" in his final test report conclusion, I must regard this problem to be a *Major* Con, as this affects the image quality seriously and especially there is NO true solution to this killing problem.

Also, as for the "phantom" bright and dark pixels revealed under pixel peeping, it is actually a mystery to Klaus and all of us.

Finally, if you read back Phil Askey's K10D review, we can now all know why Phil Askey found the problem of "soft edged images" (in-camera Jpegs or RAW converted images via Pentax PhotoLab, same here for what Klaus has found), which led to a low rating in the image quality part of the DPR review. Well, now Klaus's latest findings and explanations have indeed given full answers to the questions raised by Phil Askey, of which there was no brief answer at all even by Phil Askey himself in his DPR K10D review. In fact, Phil Askey actually did not describe the problem as clear and as specific as what Klaus has achieved - Phil Askey just wondered and puzzled for the odds he saw and then he just (told us that he) "scratched his head hard". So, afterall, I think we must thank Klaus for letting us and all Pentaxians finally know the answers to this mystery! :-) My big smile to him and thumb up!

Thursday, May 10, 2007

Pentax to Sell Tokyo HQs, Quit MF and P&S Businesses

Latest headline news of today from Japanese Nikkei Net discloses that "Pentax to Sell Tokyo HQ, Quit Low-Profit Ops to Lift Corp Value" (article in English, subscriber login required to read in full).

Here is a DPR forum thread which quotes some of the key texts of the news article, in addition to the headline preview in the Nikkei Net homepage today:-

So, now the 645D has virtually been abandoned already as it is mentioned specifically about that the MF (Medium Format) business is one of the low profit operations of the corporation. For what it is also stated about Pentax will concentrate only in the DSLR market, it simply hints that the P&S (Point and Shoot) business will also be abandoned altogether very soon in the future.

Well, to sell real estate is a quick way to cash back money to raise the company's value "instantaneously" and to increase significantly the liquidity too. It seems that the current Pentax management has a firm determination to draw more power by all means for the fight faced straight ahead, or, at least they will have more bargaining power. However, actually it is rather risky if the business still fails somedays later even when after the company has sold its property already - it's just like a gambler to fully mortgage or even sell his house and goes to the casino to gamble, i.e., he'll either just win something or get a total loss!