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09-14-2013, 06:55 AM   #31
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QuoteOriginally posted by zapp Quote
Similar problems here with K5, tried all adjustments, adjustments changed with time,AF adjustment, shimmed the focussing screen. I just don't want to spend another $1200 to fix a "simple" focus problem due to crappy design of the K5. I am currently waiting for a K5II replacement and a drop in price.

I really like the apporach of Olympus where focussing is performed on the imaging sensor. Olympus even offers more hight quality fixed focal length lenses with decent apertures and quality. I will probably sell some Pentax gear quite soon and move slowly over to an OM-D
I took a serious look at changing brands at the time and also had some real world help from a couple members here who had switch to Nikon. But the cost was prohibitive for me at the time to replace my current glass.

6 months in now with the K-5IIs and still very happy - AF is still right on all the time.

09-14-2013, 09:26 AM   #32
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QuoteOriginally posted by stormtech Quote
I've read just about every thread about the new AF system I could find for the K-5IIs. My questions comes to those of you who have gone from the K-5 to the K-5IIs, and who may have had the same problem I've been experiencing with my K-5.

The short version - AF consistency is not so great with my K-5. I guess a proper term might me AF float?

With my first K-5, after about 6 months of use, I was getting soft images little by little. When I sat down and did a focus check for my lenses, I found half of them to not be correct even at a +10 adjustment. I sent that one off to CRIS under warranty. It came back with the service performed "Adjust AF" - that was about it. After that all my lenses were spot on with no AF adjustment or no more that +-1 - great!

I ended up selling that K-5 as I had two at the time, and kept the newer one. Well, guess what - it's been about 6 months and getting the same exact thing now. No problem sending this one off to CRIS, but while this is happening I get to wonder about the K-5IIs. With this new focus system I wonder if this AF float problem has been addressed. From my reading here on the forum, it looked like Ogl and Creampuff upgraded for exactly this reason. Can anyone else chime in about this issue?

Here is a graph showing the inconsistency with my sharpest lens - FA*300 4.5. Notice the green dots - those are each shot within the same AF adjustment (4 shots taken per AF adjustment).
It seems from the graph that the best correction is zero.
This is because zero has the lower dispersion.

This kind of analysis should plot also the standard deviation, to understand dispersion.

Try to reduce distance and repeat analysis.

Last edited by gflauti; 09-14-2013 at 09:35 AM. Reason: misleading
09-17-2013, 12:54 AM   #33
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this is very interesting! My K5 also developed strange behaviour concerning auto focus. First I thought this might be fault of my lens, but no, it is auto focus.

Since I bought my K5 at amazon they offered me two choices:
1. I send DSLR to Pentax Services so they repair it
2. amazon takes DSLR back and reimburses the amount paid

I guess Iīll go with number 2, now more than ever encouraged by stormtechīs experiences.

But then again, should I go with K5II/K5IIs or should I wait till September-October and see if thereīll be new announcements.. I donīt know
09-17-2013, 01:26 AM   #34
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Bought my K5 IIs a few weeks back to shoot Moto X....seriously considered a switch to Nikon....but after reading a German test on AF where the K5 II edged out the D7100, I went with the K5 IIs.
Last weekend the image number clicked over 10,000 and frankly I could not be happier with the results....and I get a lot of feedback from customers who are very impressed and are coming back for more in increasing numbers. Sales are increasing each weekend.
Is it perfect?...no, far from it, but it does a pretty good job in difficult and demanding circumstances that makes any switch a highly improbable event.

having said that I have also recently added a D800 to my kit along with the Tammy 24-70 f2.8....but that is not going anywhere near the track. One day when I get the time I will do a comparison.

09-17-2013, 04:57 AM   #35
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QuoteOriginally posted by starbase218 Quote
This is good to know, but I do have a question. If I understand correctly, FocusTune measures the sharpness of the images. The AF adjustment for the sharpest image is then considered the "correct" AF adjustment. However, I often hear people saying they want 1/3 of the in-focus area in front of where they focused, and 2/3 behind where they focused. E.g. if you take a portrait photo and focus on the eyes, you want both the nose and most of the head to be sharp as well, stopping down as needed. But it seems to me that this is not the result you would get with this method. Or is it?

You are correct in that different focal lengths/apertures have differing field position of the target within the DoF, This is a common cause of 'adjusters' scrxwing up their cameras.

But for the test regimes mentioned here this wont happen because though a 30mm@f8 lens has 3:1 ratio @10ft (i.e 25% in focus at the front 75% at the back) the sharpest point will be at that 3:1 ratio position so the test tools will locate the correct focus adjustment.

The problem is those techniques that use finding the DoF edge then adjusting 50% inside, these are only accurate for set circumstances ie 250mm lens @f8 10ft any other lens can and do introduce horrible AF errors often causing cameras AF to fail when the AF algorithms can no longer find a solution with the DoF envelope .

Unfortunate those casual 'adjusters' tend to be the ones scrxwing over their cameras as they tend to point at a target with a wide aperture adjust till OOF one way take note of position adjust oof the other way take note and place 'adjustment ' such that the lens stops between the two noted positions = one totally miss-set camera/lens combo .
09-17-2013, 05:19 AM   #36
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QuoteOriginally posted by twophase Quote
this is very interesting! My K5 also developed strange behaviour concerning auto focus. First I thought this might be fault of my lens, but no, it is auto focus.

Since I bought my K5 at amazon they offered me two choices:
1. I send DSLR to Pentax Services so they repair it
2. amazon takes DSLR back and reimburses the amount paid

I guess Iīll go with number 2, now more than ever encouraged by stormtechīs experiences.

But then again, should I go with K5II/K5IIs or should I wait till September-October and see if thereīll be new announcements.. I donīt know
I've never been one to wait for an upcoming camera - especially from Pentax. There have been constant rumors for years now. If you want to get out there and take pics, buy a camera - end of story.

There are tons of threads about the II vs. the IIs - each person has their own reasoning for thier decision. For myself, the IIs was a no-brainier and am super happy with my decision. Going on 6+ months now with the IIs and it was one of the best decisions I've ever made regarding my gear. It is so nice to have reliable consistent AF!
09-17-2013, 07:06 AM   #37
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QuoteOriginally posted by stormtech Quote
I've never been one to wait for an upcoming camera - especially from Pentax. There have been constant rumors for years now. If you want to get out there and take pics, buy a camera - end of story.

There are tons of threads about the II vs. the IIs - each person has their own reasoning for thier decision. For myself, the IIs was a no-brainier and am super happy with my decision. Going on 6+ months now with the IIs and it was one of the best decisions I've ever made regarding my gear. It is so nice to have reliable consistent AF!
Iīm glad to hear you are having so much fun with your camera and superb AF!

hearing you itīs obvious what to do next: press "buy"-button (it will be K5II with 18-135WR for me )
09-17-2013, 07:19 AM   #38
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QuoteOriginally posted by twophase Quote
Iīm glad to hear you are having so much fun with your camera and superb AF!

hearing you itīs obvious what to do next: press "buy"-button (it will be K5II with 18-135WR for me )
I usually don't rave about much anymore as I get older, but I do with the IIs. After 2 years of frustration, and almost selling off all my beautiful FA* and DA* glass a few times, it feels so good to be able to go out and shoot and not wonder what results I am going to get.

The K-5II and 18-135WR will be an awesome setup to start for sure - please let us know your thoughts on them once you get some shooting done.

09-17-2013, 08:12 PM   #39
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QuoteOriginally posted by stormtech Quote
it feels so good to be able to go out and shoot and not wonder what results I am going to get.
How is the K-5 IIs AF when it comes to the front-focus with tungsten issue that still dogs the K-5, even with the latest firmware?

I had an uncommon but serious run-in with the problem last week while shooting a gig illuminated by tungsten floor spots, using the Tamron 28-75. The closer the subject was to a spotlight, the worse the front-focus was. And the worst front focus came from a spot covered in yellow gel, the best AF results came from spots covered in blue or green.

I didn't chimp my shots until after the gig was over, so I had to throw away lots of potentially good shots that night. If the K-5 II's new AF assembly solves this problem, I may be more motivated than ever to upgrade.
09-18-2013, 05:47 AM   #40
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QuoteOriginally posted by rawr Quote
How is the K-5 IIs AF when it comes to the front-focus with tungsten issue that still dogs the K-5, even with the latest firmware? .
Sorry - can't help you with that. I only shoot outdoors in natural light or indoors with off camera flash. Maybe someone else can chime in.......
09-18-2013, 06:56 AM   #41
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QuoteOriginally posted by rawr Quote
....shooting a gig illuminated by tungsten floor spots, using the Tamron 28-75...
Could the off-brand lens pairing be the weak link?

With the K5IIs, I've not needed to employ AF fine tuning, or other forms of focusing gymnastics, using Pentax branded AF lenses. Granted, I've missed focus, but it's been my fault and not due to the subject's illumination source.

Cheers...M
09-18-2013, 07:26 AM   #42
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QuoteOriginally posted by rawr Quote
How is the K-5 IIs AF when it comes to the front-focus with tungsten issue that still dogs the K-5, even with the latest firmware?
The K-5 II(s) solved that problem.

The AF optics are completely different.

No more front-focus under any light.
It's brilliant.
09-18-2013, 07:48 AM   #43
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QuoteOriginally posted by Michaelina2 Quote
Could the off-brand lens pairing be the weak link?
It's possible, but in the last few weeks I've shot a few gigs in mixed (and often very poor ISO 6400 territory) lighting with the same lens, and have not had many out-of-focus shots that I couldn't explain as just due to my usual bungling.

Thanks in part to Falk Lumo's work on the K-5's vulnerability to the low-light tungsten issue, Pentax put a new AF assembly in the K-30 onwards to help eliminate these sort of issues. Looks like it is working for K-5II users.
10-18-2013, 04:31 PM   #44
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Now 6 months on, have the bodies sent to CRIS kept their focus accuracy?
10-18-2013, 05:34 PM   #45
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QuoteOriginally posted by GeneV Quote
Now 6 months on, have the bodies sent to CRIS kept their focus accuracy?
Don't know - I sold them right when they were returned from CRIS. Both new owners were very happy with them and haven't heard from them since.
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