Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-03-2012, 04:50 PM   #16
Veteran Member




Join Date: Jan 2007
Location: Northern California
Posts: 475
QuoteOriginally posted by audiobomber Quote
The significant issue for me is that the K-5 AF didn't perform as well as my other bodies in tungsten light, to the point where it was totally unacceptable.


This comment was not directed you, but that's how I interpreted zxaar's comments and I've seen it elsewhere, stated more bluntly.
"You mean perhaps afflicted some K-5's with perhaps some lenses in the hands of some users."


From reading about others' experiences, I believe that K-5 bodies that were not fixed by the firmware upgrade may not be repairable. I returned the K-5 for a refund because I wasn't confident I would get a good one, but also because I didn't feel it offered enough over and above my K20 and K-x. I'm not in a hurry. I'm waiting to see what else is on the way.

Class A's original post said "Although the test shots have been made rather informally, they seem to indicate that the low-light front focusing issue that plagued the K-5 seems to be solved with the K-30."

I think we are squarely on topic with this discussion.
Sorry to hear you sent your K5 back. I got a ton of good work out of my 2 K20s and was sad to see them go, but when one could not follow the mother of the groom walking down the aisle in daylight, I knew it was time to move on.

Had the K5 AF not been fixed, I would be shooting Nikon right now although it seems they are having more than a few AF issues as well on several recent bodies.

Anyway, the diffractive optic looks promising and I hope the K5 replacement is as good or better than the K5 in all respects, especially AF if for no other reason than to talk about something else for the next decade.

I guess I had better start saving now.....

Ray

07-03-2012, 07:08 PM   #17
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,800
QuoteOriginally posted by audiobomber Quote
"You mean perhaps afflicted some K-5's with perhaps some lenses in the hands of some users."
That was me. Sorry.
That statement was blunt I guess, but the intent - with all due respect to others experience, falk's early tests etc - was to make the point that everyone's usage and equipment environment may be different.

Not all 5D's had their mirrors fall out, not all X10 users reported orbs, not all Ford Pinto users died in fireballs etc, even though there were routinely reported problems, maybe even some basic design flaws with these products.
07-04-2012, 05:47 AM   #18
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,175
Original Poster
QuoteOriginally posted by Ray Pulley Quote
The point being that the K5 seems to lock in very low light, even below the specified range of -1 ev when it should give up.
If that had been the problem, no one would have complained. Why expect more of a camera than the specs (-1 EV) promise?

Depending on the lens (e.g., slow lenses such as the kit lens) and target (e.g., Caucasian skin), the K-5 could misfocus with light levels as high as 5 EV. This could mean misfocus in studio conditions (which some reported). See Falk's respective article that he published after the "AF fix" firmware was released.

There are a number of reasons why the issue may not have been relevant to you (see for instance a number of curious factors mentioned by one of the commenters on Falk's blog that can mitigate the issue).

Luckily, we don't need to worry anymore as the last K-5 copies are being sold now and Pentax appears to have solved the low-light AF issues for the new models.
07-05-2012, 10:38 PM   #19
Veteran Member




Join Date: Jan 2007
Location: Northern California
Posts: 475
QuoteOriginally posted by Class A Quote
If that had been the problem, no one would have complained. Why expect more of a camera than the specs (-1 EV) promise?

Depending on the lens (e.g., slow lenses such as the kit lens) and target (e.g., Caucasian skin), the K-5 could misfocus with light levels as high as 5 EV. This could mean misfocus in studio conditions (which some reported). See Falk's respective article that he published after the "AF fix" firmware was released.

There are a number of reasons why the issue may not have been relevant to you (see for instance a number of curious factors mentioned by one of the commenters on Falk's blog that can mitigate the issue).

Luckily, we don't need to worry anymore as the last K-5 copies are being sold now and Pentax appears to have solved the low-light AF issues for the new models.
I have far more faith in my tests of several cameras and about 10 lenses as well as real life shooting since that time than I do in Falk's tests. No disrespect to Falk intended, I simply do not agree with him based upon my own testing and shooting.

As for people expecting the camera to focus below the specified range: the point is they often do not even realize the true light level they are shooting in. In this regard, I do agree with comments Falk made about true light level, although none of us know the exactly how Pentax defines this or measures it.

Yes, the issue was very obvious and relevant to me in the first THREE bodies I obtained and returned as it was easily seen in normal low light shooting well above -1EV. The only thing that "mitigated" the problem in any way was updating the camera firmware.

I have very conclusive before and after firmware 1.03 shots under the exact same conditions that clearly show focus shift to the rear with no other change than the firmware update. I repeated the exact same tests nearly one year later when I bought a second K5 that came with firmware 1.0. The results were exactly the same: BEFORE - FF in low tungsten light, AFTER - clear rear focus shift in the same conditions and proper focus down to the specified light level.

I find it rather amusing that so many internet "experts" somehow know more about the performance and design of a complex camera system than those who designed and built it. As if Pentax waited for months and then simply issued a firmware placebo. Right.

You are free to believe whatever you want, of course, and others may still have AF issues with their K5s. These issues could have any number of causes that may or may not be helped by the firmware update Pentax made to address the original problem.

Ray

07-06-2012, 05:50 AM   #20
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,175
Original Poster
QuoteOriginally posted by Ray Pulley Quote
I have far more faith in my tests of several cameras and about 10 lenses as well as real life shooting since that time than I do in Falk's tests.
So you are claiming that your tests are as rigourous, repeatable, and well documented as Falk's?

Did you notice that his report clearly states that he verified the issue under certain conditions only?

Have you run your tests in the same conditions?

Did you notice that he wrote that the firmware update may or may have not improved the issue under different conditions?

Why are you insisting that his experiments are incompatible with your observations? They need not be (depending on the conditions present during your tests).

QuoteOriginally posted by Ray Pulley Quote
I find it rather amusing that so many internet "experts" somehow know more about the performance and design of a complex camera system than those who designed and built it.
Do you realise that Falk knew more about the K-7 shutter blur issue than Pentax itself? Do you realise that Falk wrote an AF contrast algorithm that would even beat the improved K-5 contrast AF?

Yet you put "experts" into quotation marks and you are "amused"?

You cannot fault your K-5's AF. Good for you. But why ridicule a Physicist who clearly has sufficient expertise to give Pentax food for thought?

QuoteOriginally posted by Ray Pulley Quote
As if Pentax waited for months and then simply issued a firmware placebo. Right.
No one said it was a placebo. The firmware update helped in certain situations. However, it has been demonstrated that the firmware update did not completely fix the AF issue.

I know a Pentax dealer who is glad that Pentax eventually managed to address the AF woes of the K-5 with the new AF optics of the K-30. Why would he, if the firmware update had put an end to all K-5 AF discussions?

Let me repeat: "Luckily, we don't need to worry anymore as the last K-5 copies are being sold now and Pentax appears to have solved the low-light AF issues for the new models."
07-06-2012, 07:07 AM   #21
Inactive Account




Join Date: Feb 2010
Photos: Gallery
Posts: 488
Yea the K-5 AF is a big issue to the people that had it. I sent mine in to Japan service finally. It came back with the same problem. Two times and same problem. So, if you had the problem service did not fix it. And I finally gave up. And switched brands.
But I have some good glass for Pentax and am waiting for Falk's brand of approval.
07-06-2012, 02:53 PM   #22
Veteran Member




Join Date: Jan 2007
Location: Northern California
Posts: 475
QuoteOriginally posted by Class A Quote
So you are claiming that your tests are as rigourous, repeatable, and well documented as Falk's?

Did you notice that his report clearly states that he verified the issue under certain conditions only?

Have you run your tests in the same conditions?
I would hardly call his test rigorous, but since you do not seem to know the difference, i will leave it at that.

As for running his tests, why would I? My cameras focus properly (not without the occasional miss, but certainly better than any previous Pentax system I have owned).

QuoteQuote:
Do you realise that Falk knew more about the K-7 shutter blur issue than Pentax itself?
And you know this how? So now you have knowledge of what the Pentax Engineering team knows and does not know?

QuoteQuote:
Yet you put "experts" into quotation marks and you are "amused"?
Yes, it is amusing.

QuoteQuote:
You cannot fault your K-5's AF. Good for you. But why ridicule a Physicist who clearly has sufficient expertise to give Pentax food for thought?
Disagreeing is not the same as ridiculing, and please point out where I specifically ridiculed anyone.


QuoteQuote:
No one said it was a placebo. The firmware update helped in certain situations. However, it has been demonstrated that the firmware update did not completely fix the AF issue.
No such thing has been demonstrated. AF errors have many causes.

QuoteQuote:
I know a Pentax dealer who is glad that Pentax eventually managed to address the AF woes of the K-5 with the new AF optics of the K-30. Why would he, if the firmware update had put an end to all K-5 AF discussions?
Products and designs are improved with each release. I have no doubt that Pentax thinks the DO solution is a better answer to the problem than the color sensor/algorithm solution of the K5, and it could be that it is a cheaper solution as well. Time will tell if the DO solution fulfills the promise, but I hope it does.

QuoteQuote:
Let me repeat: "Luckily, we don't need to worry anymore as the last K-5 copies are being sold now and Pentax appears to have solved the low-light AF issues for the new models."
You do presume a lot don't you? I do not see where there is any conclusive answer that the DO optic solves the problem. As I said, I hope it does since I own a lot of Pentax gear and for many reasons do not relish the thought of moving on to another brand.

Ray
07-06-2012, 03:01 PM   #23
Veteran Member




Join Date: Jan 2007
Location: Northern California
Posts: 475
QuoteOriginally posted by Class A Quote
I know a Pentax dealer who is glad that Pentax eventually managed to address the AF woes of the K-5 with the new AF optics of the K-30. Why would he, if the firmware update had put an end to all K-5 AF discussions?"
As a last point on this subject, consider the following:

Why do we need any solution to this problem at all (color sensor or DO)? Many, including at east one poster in this thread will tell you that the K7 (or K20) did not have a FF issue in low tungsten light as if this were simply a K5 issue or something new.

It is not, it is a fundamental issue with the PDAF optical design, and all previous Pentax cameras behaved in a similar manner, including the Kr as many have reported.

Why not just go back to the K7 AF system otherwise?

Ray

07-06-2012, 03:21 PM   #24
Site Supporter
vagrant10's Avatar

Join Date: May 2007
Location: portland
Photos: Albums
Posts: 1,353
GEEEEZZZ I thought this was a thread on the k30 AF...
07-06-2012, 05:02 PM   #25
Veteran Member




Join Date: Jan 2007
Location: Northern California
Posts: 475
QuoteOriginally posted by vagrant10 Quote
GEEEEZZZ I thought this was a thread on the k30 AF...
Point taken

To get back on topic:

I have to say that I am getting tempted to try a K30 even though I have two K5s that are not getting enough use of late. The real problem with that notion is what happens later when the K5 replacement rolls out?

i will have to sell a kidney when that happens I guess.

Ray
07-06-2012, 05:29 PM   #26
Veteran Member
nulla's Avatar

Join Date: Jul 2008
Location: Melbourne Australia
Posts: 1,560
Lets hope there is only one new release after you buy the K30.... or you will finish up on dialysis

I too have the K-5 as well as the K-7 and I'm thinking seriously about the K30...LBA becomes CBA

cheers
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-30, k-50, pentax k30, pentax k50, shots, test
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Indiana prosecutor resigns for encouraging fake attack on Wisconsin governor jogiba General Talk 2 03-25-2011 07:20 PM
Informal lens test - Interesting artrutledge Pentax SLR Lens Discussion 3 06-23-2010 03:48 AM
Encouraging graphicgr8s General Talk 2 03-24-2009 09:08 PM
DA* 200 2.8 informal test codiac2600 Post Your Photos! 23 02-25-2008 03:58 AM
DA* 200 2.8 informal test codiac2600 Pentax News and Rumors 1 02-24-2008 08:36 PM



All times are GMT -7. The time now is 05:45 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top