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01-08-2011, 11:11 AM   #1
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Relevant news re malfunctioning AF under artificial light

As the administrator, for good reasons, has closed the former thread re this issue I would like to suggest that the issue still has a right for following up in this forum so please post your RELEVANT developments/ thoughts/ ideas/news in this thread so we can keep an eye on the issue as long as it is not solved.
Agree ?

01-08-2011, 11:20 AM   #2
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I agree-we definitely need a thread like this!

Andras
01-08-2011, 01:27 PM   #3
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Maybe for household purposes you should have added a link to the old thread

https://www.pentaxforums.com/forums/pentax-k-5-forum/126234-who-cares-bad-aut...ten-light.html
01-08-2011, 03:31 PM   #4
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Why has the original thread been closed? I dont get it.. is the AF under tungsten problem solved? Did it never existed in the first place? Whats going on?

01-08-2011, 03:57 PM   #5
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QuoteOriginally posted by Becks21 Quote
Why has the original thread been closed? I dont get it.. is the AF under tungsten problem solved? Did it never existed in the first place? Whats going on?
mods didnt explain that... i was afraid to ask.... it reminds me old times of comunism in east europe - one day newspaper prints next day all editors are canned.... maybe it was some kind influence from Pentax?:ugh:
01-08-2011, 04:02 PM   #6
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FYI, my k-5's AF works fine under artificial light. I don't know if it relevant or not, my serial number is 3970***.
01-08-2011, 04:13 PM   #7
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I agree with Bjan that there is a need for this thread and that it shouldn't have been closed. This also recently happened to the "K5 sensor stain" thread, which is also a good reference for all current/future K5 users.
The Tungsten-AF issue has not been solved and we need to keep informed of any further and RELEVANT information on that subject.
Ditto for the sensor stain issue.

However:
Closing a thread usually means that there has been a "departure" from what the main subject of the said thread should be.
That is what I notice each time a thread is closed; "departure" as in: friction, hostility between some members, discord and/or simply continuous "out of context" postings, aside from a duplicate or timed out thread (old with no response).
And there have been loads of wasteful comments in both threads in spite of their originally obvious
and relevant nature.
Some people just like to make trouble and that is the price we pay for it: elimination.

I don't think the admin would close a thread unless it has become totally useless or that it has become a fighting arena.

My belief is that the thread was closed for pertinent reasons but I sure would like to have it back "alive" (sensor stain thread too).

If the admin agrees to resurrect them (threads), we will have to make sure that each post is relevant to the subject(s) at hand and that any garbage dumping should be reported to the admin which will likely take care of the trouble makers.

My ten cents!

JP
01-08-2011, 04:18 PM   #8
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A poster at Flickr just got his replacement yesterday for the stained version he had, and reports it has no problems with stains, flash bounce or focus in any light. #3965XXXX

Reports good or bad should include a S# if we are to make any solid relationship to the problems reported.
Regards!

01-08-2011, 04:21 PM   #9
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im glad the old thread was closed, this has been done to death ..I don't think any of us have any think new to say until a firmware update comes along...other than that its just beating the same drum....and the noise is getting repetitive

so my advice for what its worth..is get shot of your camera or work within it short comings and sit tight until firmware 1.03..the choice is yours..

me , Im waiting for 1.03

EDIT

as for reports that this works. or that doesnt..Id take em all with a pinch of salt...as for what ive read so far..the blokes that say theirs work are doing the test wrong..eg too far away and to great a DOF.......

As I said at the begining of this post...sit tight for 1.03...if no better..try a exchange body..and if that dont work..and this is important to YOU..get shot of your pentax
01-08-2011, 04:56 PM   #10
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In the spirit of Glasnost: the AF issue and sensor stain threads were closed because the discussion got off-topic/unproductive and - worse - unfriendly. As far as I know starting new threads to continue to discuss the actual issues is absolutely fine, if you feel that it is still needed.
01-08-2011, 06:59 PM   #11
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I'm happy to report in on my K5. Serial #3965xxx as well.

Tested on all lenses, only 2 of my Sigma lenses exhibit serious FF issue in really low light level. How low? ISO 10,000 f2.8 1/40s low. (how many EV is this?)

The 2 Sigma lenses are 30mm 1.4 and 50mm 1.4. Both focuses fine in better light.

Suprisingly the DA* 16-50 actually focuses quite well under such low lighting level, better than my other DA limited.
01-08-2011, 07:43 PM   #12
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QuoteOriginally posted by Tommot1965 Quote
im glad the old thread was closed, this has been done to death ..I don't think any of us have any think new to say until a firmware update comes along...other than that its just beating the same drum....and the noise is getting repetitive

Some with new models are reporting better results, that is worth hearing...isn't it?

so my advice for what its worth..is get shot of your camera or work within it short comings and sit tight until firmware 1.03..the choice is yours..

me , Im waiting for 1.03

EDIT

as for reports that this works. or that doesnt..Id take em all with a pinch of salt...as for what ive read so far..the blokes that say theirs work are doing the test wrong..eg too far away and to great a DOF.......

Just not so, the owner I reported as well as another one on Flickr are long time shooters, and well qualified to do the testing. Their results may or may not signal a change in the newer models, or just a random chance happening, but it is not fantasy either.

As I said at the begining of this post...sit tight for 1.03...if no better..try a exchange body..and if that dont work..and this is important to YOU..get shot of your pentax
Let's see what people report...we have heard the bad and ugly......there may be some good to report,L let's let it be heard. No need to argue, bash, or flame, just report what you find and I am sure this thread can stay open and be of benefit.
01-08-2011, 09:02 PM   #13
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QuoteOriginally posted by Rupert Quote
A poster at Flickr just got his replacement yesterday for the stained version he had, and reports it has no problems with stains, flash bounce or focus in any light. #3965XXXX

Reports good or bad should include a S# if we are to make any solid relationship to the problems reported.
Regards!
Did this poster at Flickr have the focus problem on his original K5? If a user who was able to consistently recreate the focus issue on a body is not longer able to with a replacement that would be much more meaningful than if the user didn't see the issue on the original body.
01-08-2011, 10:18 PM   #14
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3rd Body Report

Got my 3rd K5 this week (first one had sensor stains, second one front focus issues, 3rd is stain free but still has FF).

It appears to be a bit better in low light, but still has significant front focus at EV 2-3.

Here is a test sequence, 3rd K5 on top, 2nd K5 in the middle, K20 last, EV 11 on the left to EV 2 on the right:



FA 50 @ f2.8, ISO 100, AF and 2 sec MLU/Shutter release tripped by IR remote. No sunshine today, so I used my SSC P7 led flashlight to illuminate the target and placed ND filters over the light to reduce it 8 and 10 stops.

Note that "white" leds are not really white as they have very little response in the red spectrum. In this case, the camera saw more and more green as the led light was reduced, which is another nail in the IR color shift myth. The SSC P7 LED white led is nominally 6400K and I measured 6150 at full brightness, 5400 at the lowest light level, so this test does not isolate color vesus light level, not that I believe this makes any difference, as I do not.

All AF adjusts were reset, so you can see some differences in starting focus point.

The good news is that while the 3rd K5 (top) still has a bad shift at the lowest light level, it holds up much better to just above the steep drop-off at EV 2-3.

It may be that I can dial AF adjustments that are biased towards the back a bit in bright light and still get good focus at least to EV 2-3 or so.

The K20D works just as I expected. It tends to FF as well, but is much less certain in getting a lock in low light, hunting a bit more and actually locking into a somewhat worse FF position in the middle image than in the lowest light. It is much better at the lowest light level than either K5.

I had the FA 50 dialed to a bit of BF in daylight on the K20D, which keeps it within the DOF as the ight is reduced.

So, I have tested my cameras with reduced daylight, reduced tungsten light, reduced led light that shifted green and also with different colors, and the only consistent result is that the camera shifts to FF as the light is reduced and has a steep FF shift somewhere around EV 2-4.

There may well be K5s that do not FF this badly at EV 3 and below, but I am on my 3rd body and they all had a very similar problem in low light. I would really like to see a test from a K5 at EV 2-3 F2.8 or so that does not FF like this. At least then I would have some hope that the K5 can focus somewhere near the advertised specification of -1 EV.

No more testing for me, however, as I am convinced that there is a consistent AF problem with the K5 and I have little faith that Pentax will do any more about this than they have with SDM failures, or KR FF in low light issues, or K10D AF in low light issues.

I guess that I need to decide if it s time to seriously consider moving to another brand, as much as I do not want to do so for many reasons.

Ray

EDIT: 2nd K5 has latest firmware (middle images) 3rd K5 does not (top images).

Last edited by Ray Pulley; 01-08-2011 at 10:23 PM. Reason: Add note
01-08-2011, 10:19 PM   #15
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QuoteOriginally posted by JamieP Quote
Did this poster at Flickr have the focus problem on his original K5? If a user who was able to consistently recreate the focus issue on a body is not longer able to with a replacement that would be much more meaningful than if the user didn't see the issue on the original body.
You can ask him yourself, he is Jthommo, down the page here with the great little Birdie shot.
https://www.pentaxforums.com/forums/pentax-k-5-forum/123731-no-more-tests-just-pictures-18.html

As I recall, he was not having the problem on his sold one, but I can't be sure he actually tested the old one for the problem if my memory is correct. It is one of the mysteries of this problem....some do, some don't, some will, some won't. Answers are bound to come soon.
Regards!
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