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01-04-2011, 12:22 PM   #346
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QuoteOriginally posted by Ray Pulley Quote
Hi Falk,

I did some tests today and the results are interesting and somewhat puzzling at the same time.
Ray, no offence, but I don't think your results can be very reliable. The tripod is obviously wobbly and you left your finger on the shutter release, causing visible shake. The only way to do this test IMO is with the 2s delay. You may need a 10s delay considering how unstable the tripod looks.

01-04-2011, 03:11 PM   #347
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QuoteOriginally posted by jbinpg Quote
Just curious, is there any difference in AWB versus Tungsten WB as far as focussing accuracy?
The AF system, if like previous models, is situated in the bottom of the camera and fed by a small secondary mirror. nothing to do with colour balancing.
01-04-2011, 03:20 PM   #348
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QuoteOriginally posted by Smeggypants Quote
The AF system, if like previous models, is situated in the bottom of the camera and fed by a small secondary mirror. nothing to do with colour balancing.
But some cameras (I believe I read somewhere) adds some sort of compensation value to the AF if the WB is set to tungsten light.
01-04-2011, 03:39 PM   #349
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Pentax USA Response to Issue

Just received this today from Pentax Techncial Support in the USA based on my question.

Pentax Japan has not informed us of any known issue with the K-5 autofocus system malfunctioning under low tungsten light. Also, our shop has not received any K-5 cameras for us to examine for this issue..........."send it in". I have this issue like many of you, no stains though.

Thought you all might be interested ,doesn't sound too promising.

01-04-2011, 07:25 PM   #350
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QuoteOriginally posted by soaks Quote
Just received this today from Pentax Techncial Support in the USA based on my question.

Pentax Japan has not informed us of any known issue with the K-5 autofocus system malfunctioning under low tungsten light. Also, our shop has not received any K-5 cameras for us to examine for this issue..........."send it in". I have this issue like many of you, no stains though.

Thought you all might be interested ,doesn't sound too promising.
So how is a Firmware fix going to solve a problem that Pentax has never heard of? Could someone point them in the direction of the internet and two Forums that are overflowing with this subject? No, you are absolutely right, it does not sound promising......
Regards
01-04-2011, 08:51 PM   #351
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QuoteOriginally posted by Rupert Quote
So how is a Firmware fix going to solve a problem that Pentax has never heard of? Could someone point them in the direction of the internet and two Forums that are overflowing with this subject? No, you are absolutely right, it does not sound promising......
Regards
Go back and read it again, but absolutely literally.

"Pentax Japan has not informed us......"

It's actually pretty disingenuous.
01-04-2011, 09:55 PM   #352
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I am using a K-R with similar tungsten front focus issues. I realize it's a very different camera than the K-5 but they might share some autofocus calculations and other firmware routines.

Most of my front focus issues go away if I manually set my WB from Auto to Tungsten. So, at least on the K-R, white balance and autofocus seem interconnected.
01-05-2011, 02:06 AM   #353
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They need to take the K-x's AWB code and put it into the K-5 / K-r the K-x's was flawless.

01-05-2011, 04:09 AM   #354
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QuoteOriginally posted by DeadJohn Quote
...
Most of my front focus issues go away if I manually set my WB from Auto to Tungsten. So, at least on the K-R, white balance and autofocus seem interconnected.
Using the manual WB setting as a clue to fine tune the AF sounds like a sensible thing to do; from this thread I understand that the K-5 AF sensor has this built-in so the compensation seems like worth doing (right ;-). The problem using AWB for that is this is based on the captured image (I assume) so it is too late to adjust focus when a figure is available from this. If my assumption is correct, there could be a function akin to stop-down (green button) metering for this or maybe using the calculated AWB from the previous frame :-)
01-05-2011, 07:39 AM   #355
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QuoteOriginally posted by Rupert Quote
Well, for Ray this is a real obstacle in his work, and assuming that he is honest in his experience, and I have no reason to believe he isn't...he does appear to be a loyal Pentax a shooter, this will need to be corrected or many will be unable to fulfill their duties or find much joy in this camera.
It is only fair that it work as well as past models, and although it might or might not affect me personally, it should not be adverse for others. If I got a new K5 and found it was missing the video....I would never say a word....maybe a little chuckle to myself, but for others this would be a disaster. We need to think of everyone, not just ourselves. My recommendation is to send back any camera that does not perform to the specifications promoted. Do it until you get one that does or just get a refund. An unhappy shooter is no fun, and life is too short for that to happen.
Best Regards!
My reason for thinking that this is, to a certain extent, a tempest in a teapot is because people are "testing" this sort of stuff at very close focus distances, designing "tests" to make sure the equipment fails and then reporting back that they were successful.
I could take my truck and design a test to see if the body would bend in a head on collision and then report back that my truck is wrecked. Testing to failure is easy.

Certainly there appears to be a problem at arms length (the video a few pages back was shot at less than a foot), but is it going to be as big a problem at 10 feet as it is at 10 inches from the subject?
Common wisdom dictates that for macro, one should use manual focus anyway....

Frankly, I've never had any success with Pentax AF. When the chips are down, Pentax AF has always failed me, irregardless of camera. The best AF I've gotten was using LiveView AF with the K5 in the studio.
It was pretty fast and deadly accurate.
At weddings, I've had AF fail enough times that I just don't use it. K10, K20, K7 have all had one problem or another that for me renders the AF to be useless due to lack of trustworthiness to get a picture at the right time.

My question is, do you think that if they get the AF sufficiently accurate down to EV 0 or so that people will stop complaining, or will they still complain because they can take good pictures at EV -3 or -4 and the AF isn't working?
01-05-2011, 07:53 AM   #356
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QuoteOriginally posted by Wheatfield Quote
Certainly there appears to be a problem at arms length (the video a few pages back was shot at less than a foot), but is it going to be as big a problem at 10 feet as it is at 10 inches from the subject?
In my case it was. The camera focused near my feet whatever the distance between me and the subject. The EXIF shows the correct AF point was used, and was considered "in focus" by the camera, but on the picture its area is totally out of focus. It has happened many times and I was able to reproduce it at home.
01-05-2011, 07:55 AM   #357
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QuoteOriginally posted by Wheatfield Quote
At weddings, I've had AF fail enough times that I just don't use it. K10, K20, K7 have all had one problem or another that for me renders the AF to be useless due to lack of trustworthiness to get a picture at the right time.
Then you should be complaining as well, or at least let us complain that don't find that acceptable.
The difference from my k10 is when the k10 failed I knew it, it would hunt and then give up. The k5 makes a quick move, beeps and lights up the green hexagon, but it is out of focus. And in Sweden at this time of the year it's dark when I go to work and it's dark when I get home. So the problem is there most of the time, no artificial test has to be invented.
01-05-2011, 07:57 AM   #358
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Sometimes it works and sometimes it does not...

I am a bit disappointed actually, I expected more from the FLAGSHIP model with all the hype re new safox etc. My copy was not better in terms of AF performance than my K-x... hit and miss in low light when shooting at f1.4 Sometimes it locks very fast and far out, like 1/3 of the distance from the subject focusing on apparently empty air. For these conditions - split image focusing screen and MF (or at least to see where it focused, if you use AF)

Here are two decent shots - one with K-x, one K-5. (out of several dozens taken just to get these two).

Shame the K-5 has sensor stains and now is unusable at any f number over 8. Sending it back.
Attached Images
View Picture EXIF
PENTAX K-x  Photo 
View Picture EXIF
PENTAX K-5  Photo 

Last edited by Mikhail_Kriviniouk; 01-05-2011 at 12:25 PM.
01-05-2011, 08:03 AM   #359
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Wheatfield, this again is a reasoned response, but there are so many frustrated K5 owners that it does tend to make me, and most likely many others, more than just a little gun shy. Beating up on Pentax is not a solution, we all have done it either here or in our own minds, but that will solve nothing. What we need now is some confidence building information from Pentax to assure us that these problems will be corrected, as has been done with the sensor stains.......which could have been prevented, but could have also happened with any Brand camera as I see it.

The K5 is maybe my last camera, I am not as young as I was just yesterday it seems....and with my K20D as a backup the K5 could easily be all I might desire for a long time. Frustration is not a thing you seek out when you are older, you have plenty already. I think the current frustration is what is the most annoying of all this, you just get that feeling with every new post. I'm not in a really big hurry, so will watch and listen, but at some point I will have to decide and make a choice. Some already have and have left Pentax....some have gone with the K5 and been disappointed...some very satisfied.......more frustration!

As always, I appreciate your response. I have been a loyal Pentax user, and well satisfied with most products and operations, and want to stay the course.......I hope Pentax will help me do that.
Best Regards!
Rupert
01-05-2011, 08:13 AM   #360
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yep thats quite true.at 1 meter a 50mm F2.8 lens will only have 40mm DOF..at 2 meters that goes up to 180mm..perhaps enough for the increase in DOF to mask the issue

but if in a church service {weddings} using a 70-200 F2.8 at 135mm at 5 metres { just at the end of the pews} the DOF is not huge 150mm...would that start to get to the limits of what the DOF can mask in a real world situation...

but your are right though wheatfield to a degree...and you do talk quite a lot of sense

and for everyone that thinks im so clever now..due to me spouting these DOF measurements...get the DOF master for your Iphone..its bloody awesome..LMAO
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