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03-16-2008, 01:13 AM   #1
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Improved Continuous AF Tracking of the K20D

A new K20D user has made an interesting and systematic comparison test in comparing the AF-C hit rate and performance with his new K20D against his old K10D :-

我對pentax之前的感想,及k20d的用後感. - Pentax 討論區 - DCHome.net 數碼天地論壇 *輕銌臚@*蚍すX相機網站 - Powered by Discuz!

(Text in Traditional Chinese, use Babelfish if required)

What's the most interest test he did is the "Goldfish Test" (to be exact, the goldfish is called "Peacock"), he used a stop watch/time counter, set it to five minutes and then put his K10D or K20D in AF-C mode. There are 11 numbers of the goldfish in the tank. Each time he focused on one fish. After the focus confirmation is achieved, he focused on another nearest fish and repeated the test for five minutes. The number of taken shots was then counted and then the shots were then classified into "Good", "Fair" and "Bad" according to the sharpness in focusing or the amount of out-focusing. For example, "Bad" shots were those totally out-of-focus ones which are not usable and should go to the trash bin anyway, "Fair" means that there were slight out-focusing in the shots, but the amounts of errors were yet acceptable.

So, here are the raw results of his:-

K10D: 64 shots taken: 14 "Good", 23 "Fair", 27 "Bad";

K20D: 90 shots taken: 30 "Good", 44 "Fair", 16 "Bad".

Thus, it's obvious that the K20D has smarter continuous AF tracking ability than the K10D. The K20D had taken 40% more photos within the time limit! .. which simply means more photo opportunities which I have been emphasizing on from time to time.

I tabular the following on the successful, failure and in-between rates by simple calculations for our more easy reading:-
Camera
Good
Fair
Bad
K10D
21.86%
35.94%
42.19%
K20D
33.33%
48.89%
17.78%

So, for ideal "Good" shots, K20D has a 52.47% improvement (by comparing the numbers of "Good" shots) over the K10D although the hit rate of 33.33% is still on a low side IMHO and there is pretty room for improvement. As for the "Bad" share of shots of total failure, the difference between the two cameras are huge. That means that the "usable" rates for acceptable pictures, in counting both "Good" and "Fair" are 57.8% versus 82.22% for the K10D and K20D respectively. Oh well, for the K10D case, I can't think out a better quick phrase to describe that what "hit and miss" could tell for a such a low hit rate on even "Acceptable" shots - nearly one picture out of two is trashable for the K10D!(?)

Do note also that the user had also tested the AF-C for *static* objects, which he found NO difference between the K10D and the K20D. But, who would use the AF-C mode for shooting *static* objects then?

Besides, the user has also done some quick checking on the image quality differences between two cameras. We can note the purple fringing difference and the noise level difference in the comparison shot he made and posted along the above same thread which shows that the K20D is just better.

So, now back to the AF issues, as stated in the user's above opening post. In fact, he has been much dissatisfied with the AF performance of his old K10D owing to the poor AF-S accuracy that decreased the resolution (and thus decreased the image quality of his good lenses) and the inferior AF-C performance as well. As such, he just took a gamble to go ahead to acquire the K20D without second thought as he just won't want to switch, he told. Well, just as one responded poster said, he was considered to be "very brave", as he had already found that the K10D to be performing so poorly in the AF department. I do second this viewpoint totally - just imagine IF the K20D's AF is actually identical to the K10D's one, then!?

In fact, I found that Pentax has once again to be 200% unwise (or simply *stupid*, I would say) to tell the world that the K20D uses the SAFOX VIII AF system, which is actually infamous for poor AF speed, low light performance and accuracy. In fact, since it has been verified that various new K20D users have found *improvements* of the AF for the K20D. WHY don't Pentax just tell us it is of an improved version, say, it can be named as SAFOX VIII E (Enhanced) or something, just to tell the difference.

Indeed, to explain such stupidity, it is just the typical and classic Pentax behaviour - they never admitted problems and tried to hide them as far as possible! BUT why not let the old bugs in the past over and be *positive* in promoting their new products? What wrong to tell the world that they have debugged (or maybe just using the word "improved" marketing-wise) the old system (although after so many years) and now they have been able to bring out a better version of the SAFOX VIII. I think it should still be a very positive thing afterall!

Original article with all the quoted URLs contained:-

RiceHigh's Pentax Blog: Improved Continuous AF Tracking of the K20D


03-16-2008, 01:29 AM   #2
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Thank you for scouring the net to find this piece of trivia.

I am under no illusions as to the Pentax AF system, I have read countless reviews and read the results of many tests, both professionally done tests and the obscure amateurish ones that you, ricehigh, seem to delight in. (Particularly if they put Pentax in a bad light.)

As a consumer on the internet I have al sorts of information at my fingertips and I still personally find the Pentax cameras to be superior in value to any other camera brand. This is my opinion and I have a right to it.

I also find the AF on my *istDS to be more than adequate for my requirements and from my research I have come to the conclusion that the Pentax K20D has even faster AF. Not to mention the many other benefits the Pentax system offers over competing systems.

Hence I will not be taking your advice, Rice High, and I will be purchasing a K20D. I could chose any camera I wanted including a Nikon D3 if I really, really wanted. But I gathered all the information relevant to my needs and the Pentax K20D rises to the top.
03-16-2008, 01:48 AM   #3
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If you have a DS now, I do believe the K20D is a real upgrade to you with many improvements that can be found in your coming new camera.

In fact, I did find that my K100D is quite lovely and had been improved somehow when I compared against my old DS, which I shared my experiences in my following report after I got and had used my K100D for a trip:-

RiceHigh's Pentax K100D Full Review

Having said that, the K100D (and the K10D) had been fell short of something that did not fulfil some of my daily needs and thus I needed to get a 5D at last.

QuoteOriginally posted by Falcons Quote
Thank you for scouring the net to find this piece of trivia.

I am under no illusions as to the Pentax AF system, I have read countless reviews and read the results of many tests, both professionally done tests and the obscure amateurish ones that you, ricehigh, seem to delight in. (Particularly if they put Pentax in a bad light.)

As a consumer on the internet I have al sorts of information at my fingertips and I still personally find the Pentax cameras to be superior in value to any other camera brand. This is my opinion and I have a right to it.

I also find the AF on my *istDS to be more than adequate for my requirements and from my research I have come to the conclusion that the Pentax K20D has even faster AF. Not to mention the many other benefits the Pentax system offers over competing systems.

Hence I will not be taking your advice, Rice High, and I will be purchasing a K20D. I could chose any camera I wanted including a Nikon D3 if I really, really wanted. But I gathered all the information relevant to my needs and the Pentax K20D rises to the top.
03-16-2008, 01:52 AM   #4
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Hey RH, go test your Infallable Canon please

03-16-2008, 01:52 AM   #5
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QuoteOriginally posted by Falcons Quote
Thank you for scouring the net to find this piece of trivia.
The finding and conclusion as dug out and made by that K20D user is in fact NOT trivial.

How could we know that the K20D's SAFOX VIII is different than the SAFOX VIII of the K10D if it is not tested? Do remember that they both appear exactly the same as on Pentax's official papers and the AF speeds for still objects are verified to be the same by the experiment!

What makes the difference is when the cameras are used for tracking moving objects, in AF-C mode and continuously!
03-16-2008, 04:45 AM   #6
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QuoteOriginally posted by RiceHigh Quote
Indeed, to explain such stupidity, it is just the typical and classic Pentax behaviour - they never admitted problems and tried to hide them as far as possible! BUT why not let the old bugs in the past over and be *positive* in promoting their new products?
This is one thing that amuses me - everyone accepts that Pentax's marketing is terrible (mostly by its nonexistence) - but nobody ever follows this logically to its conclusion.

Why doesn't Pentax claim the AF is improved? Why don't they brag about their backwards compatability? Why do they not make a fuss out of the DA lens focus clutch? Why don't they prominently point out the advantages of in body SR? Why don't they show off how ideal the DA limited pancake range is for street shooting?

You're asking why they aren't saying anything about the autofocus - you're blind - Pentax never promotes ANYTHING.

Which is probably why Pentax gear is so much cheaper than C & N...
03-16-2008, 04:58 AM   #7
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One possibility is that the autofocus system isn't improved as such, but that the camera has a faster CPU and other components, which allows faster updating, resulting in better continuous AF results.
03-16-2008, 05:20 AM   #8
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In the presentation of the new model in Dubai, Pentax stated that the AF of the K20D was "tweaked" with new computation algorithm to improve it. I would be curious to see how Canikons would fare with the "fish tests"!!!!!!

03-16-2008, 07:09 AM   #9
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QuoteOriginally posted by cpopham Quote
This is one thing that amuses me - everyone accepts that Pentax's marketing is terrible (mostly by its nonexistence) - but nobody ever follows this logically to its conclusion.
The first Pentax marketing guy I have ever seen who knows how to promote and sell Pentax products should be Ned Burnell.

QuoteQuote:
Why doesn't Pentax claim the AF is improved?
Just because the slow and inaccurate AF has been the main thing which many many Pentaxians have been complaining about for years with their DSLRs.

It's totally unwise if they have improved the AF but just try to keep their efforts spent to be a secret!

QuoteQuote:
Why don't they brag about their backwards compatability?
Since the introduction of the cripped K-mount, the backward compatibility is already poorer. What do you expect they could promote?

QuoteQuote:
You're asking why they aren't saying anything about the autofocus - you're blind - Pentax never promotes ANYTHING.
Even they do not promote anything, they should let the world know they have made something new and better.

How many times have we seen old Pentax DSLR users said that "I shall not upgrade", "just because the new DSLRs do not have much more things new", i.e., the AF and AE are speced to be the same.

QuoteQuote:
Which is probably why Pentax gear is so much cheaper than C & N...
Not really. Pentax gear is not particular cheaper nor they are really better as long as body performances are concerned, generally speaking.
03-16-2008, 07:14 AM   #10
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QuoteOriginally posted by flyer Quote
In the presentation of the new model in Dubai, Pentax stated that the AF of the K20D was "tweaked" with new computation algorithm to improve it.
Not many people are interested in the Dubai secret press conference anymore as time goes by, nor we knows much about the contents of what Pentax's presentation told.

QuoteQuote:
I would be curious to see how Canikons would fare with the "fish tests"!!!!!!
I'm pretty sure that it should be better. If in five minutes the K20D managed to take 90 shots in AF-C mode, which means that it requires 3.33 seconds to take one photos after successfully to track the fish and achieved the AF. My experience with my Canon (5D) is that in AF-C mode (or just AI focus) the shooting rate is much higher (and results are good with quite high hit rate too) even with very fast and randomly moving objects, e.g., pets and little children.
03-16-2008, 03:25 PM   #11
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QuoteOriginally posted by RiceHigh Quote
Not many people are interested in the Dubai secret press conference anymore as time goes by, nor we knows much about the contents of what Pentax's presentation told.
People are always interested in facts.
03-16-2008, 03:29 PM   #12
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QuoteOriginally posted by RiceHigh Quote
Just because the slow and inaccurate AF has been the main thing which many many Pentaxians have been complaining about for years with their DSLRs.
Every body agrees the AF on the Pentax is SLOWER then Canikons, not slow.
Nobody ever said, as far as I know, that it is inaccurate, quite the opposite. A lot of report said it was as accurate, if not more, than Canikons.
Talking about autofocus accuracy, I'd like to remind you that Canon is having some with their latest 1D and 1Ds MkIII. And those cameras are selling for something like 4 times the price of a K20D... Maybe you should look in your yard before looking in the neighbor's yard!

Last edited by flyer; 03-16-2008 at 03:35 PM.
03-16-2008, 04:31 PM   #13
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QuoteOriginally posted by RiceHigh Quote
Just because the slow and inaccurate AF has been the main thing which many many Pentaxians have been complaining about for years with their DSLRs.
As a previous poster said, nobody really says it is inaccurate, just that it's slow. I do wonder though, how a lot of these tests would fare if the set up for both cameras was the same. E.g. how does a Pentax with an SDM lens compare with a Canon with an USM lens I wonder (obviously given the same focal length and maximum aperture) I don't think I've ever seen this kind of comparison done, it would be interesting.

QuoteOriginally posted by RiceHigh Quote
Since the introduction of the cripped K-mount, the backward compatibility is already poorer. What do you expect they could promote?
The fact that even the cheapest Pentax SLR can mount, and use, basically every Pentax K mount lens ever. How can you possibly say that's bad? You can't say it is "poorer" without comparing it to something else, what else would you compare it to?

QuoteOriginally posted by RiceHigh Quote
Even they do not promote anything, they should let the world know they have made something new and better.
Did you even read what you wrote? How does that sentence make any sense at all?
"Even if they do not promote anything, they should promote something"
WHAT?!

QuoteOriginally posted by RiceHigh Quote
How many times have we seen old Pentax DSLR users said that "I shall not upgrade", "just because the new DSLRs do not have much more things new", i.e., the AF and AE are speced to be the same.
I'd suspect Pentax probably aims to make most of it's money from lenses rather than bodies anyway. Besides, we don't usually see that all, we tend to see people who have one body and one to two lenses writing "Selling everything, moving to <insert other brand here>". Or worse, lingering here and complaining... If a person truely believes one camera system suits them better than another, they should change...

QuoteOriginally posted by RiceHigh Quote
Not really. Pentax gear is not particular cheaper nor they are really better as long as body performances are concerned, generally speaking.
I never said the bodies were significantly better, but I don't think they're any worse either. It certainly seems to me that you can put a Pentax kit together much cheaper compared to some of the competitors. Yes, many of your lenses will not be SDM, but this becomes less important when your body actually has a focus motor... and then you can choose to pay the premium for SDM lenses in the focal lengths where it most benefits you (well, once they finally make the damn things available that is...)

Not wanting to come to close to an ad hominem attack, but honestly, your post prompted me to go and take a look at your blog. Don't you have better things to be doing with your time, like, say, going out and taking pictures? Surely that's more enjoyable than maintaining a giant list of everything you consider wrong about a manufacturer's products?

If you really dislike Pentax so much why aren't you outside taking pictures with whatever brand you consider superior rather than lurking here, borderline trolling?

Last edited by cpopham; 03-16-2008 at 04:37 PM.
03-16-2008, 05:39 PM   #14
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QuoteOriginally posted by cpopham Quote
As a previous poster said, nobody really says it is inaccurate, just that it's slow. I do wonder though, how a lot of these tests would fare if the set up for both cameras was the same. E.g. how does a Pentax with an SDM lens compare with a Canon with an USM lens I wonder (obviously given the same focal length and maximum aperture) I don't think I've ever seen this kind of comparison done, it would be interesting.
Actually, such a test has been performed , and the winner was....
Actually, they were more or less even (they used the Pentax 50-135 vs a Canon 70-200 or something close to that).
Found out that test on a French website this morning. Sometimes it pays to be living in Quebec (not all the time).
03-16-2008, 06:31 PM   #15
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k10d for sports

Attachment 9636

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HI Rice, If the k10d is as bad as u say why do i get shots like these with no probs.The snowboard pics taken with Tamron 80-210mm $150 brand new and the footy shots with Sigma 100-300mm $60 used.Im not even thinkin about gettin K20D cause im so happy with the results i get with the k10d.more importantly my customers are always happy with the quality of shots i get.So if you can put a cheap zoom on your 5d and show us the quality you get with it.I shoot sports every weekend and havent even had to consider a nikon or cannon more than happy with what i got .

Last edited by trumpyman; 03-17-2008 at 06:11 AM.
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