who cares for bad AF under tungsten light ?

bjan · 12-28-2010, 02:11 PM

Originally posted by Gimbal

My main lens is a Sigma17-70 and the FF is most obvious (by far) at the 17mm end, a meter or so in error on a 2,5 meters distance is the norm.

Things get more and more out of control I guess ! Hope PENTAX adresses the issue very quick as it gets worse the more people start looking into the matter. Hundreds of reactions in this forum and hundreds in German and other forums around the globe affirming the issue is not a simple issue anymore I suggest . But our Japanes friends remain silent as if it is not their problem ! If the problem ever gets solved I hope I served the situation with the start of several threads on the internet. I will step out a bit now because I might be seen as a troll by some and that would do the case no good as it is very serious but the issue can "float" on its own I assume after initiating. Thanks for all your input .

deejjjaaaa · 12-28-2010, 02:23 PM

Originally posted by bjan

Things get more and more out of control I guess

nothing is getting out of control - I 'd say things are just not getting 1-2 magnitudes better in that very-very specific department (even the AF from Pentax in general is becoming better and better)... it is not a new problem - it is the old problem since *ist's (digital) days... and I just can't understand what is the problem to allow to have 2 sets of AF adjustments in firmware... you have AF adjustments already in place, it is already an acknowledgment that your AF is not perfect - so just make it better, make it 2 sets (for daylight and tungsten) and also make it like Olympus did - tunable for zooms @ wide, middle, long ends... we are not even asking to make it like Olympus did tunable per each AF point

jolepp · 12-28-2010, 02:53 PM

Originally posted by deejjjaaaa

... and I just can't understand what is the problem to allow to have 2 sets of AF adjustments in firmware...

I understood from a previous post that this sort of thing can in fact be done with the K-5 user modes?

Wheatfield · 12-28-2010, 03:06 PM

Originally posted by bjan

Things get more and more out of control I guess ! Hope PENTAX adresses the issue very quick as it gets worse the more people start looking into the matter. Hundreds of reactions in this forum and hundreds in German and other forums around the globe affirming the issue is not a simple issue anymore I suggest . But our Japanes friends remain silent as if it is not their problem ! If the problem ever gets solved I hope I served the situation with the start of several threads on the internet. I will step out a bit now because I might be seen as a troll by some and that would do the case no good as it is very serious but the issue can "float" on its own I assume after initiating. Thanks for all your input .

Ahh, trying to drive up the hysteria meter again I see.

Malake · 12-28-2010, 03:18 PM

Quote:

My main lens is a Sigma17-70 and the FF is most obvious (by far) at the 17mm end

Same with my combo Nikon D90+Sigma 17-70, even in good light.

**jpzk** · 12-28-2010, 05:05 PM

Apologies to barge in on a very technical thread in which I have not much to offer "technically".

I have just spent half an hour reading through the posts here (I am a slow reader) and I am hoping someone would provide some "tips" on how to test the K5 for AF in dimmed Tungsten light when I go to the store on Friday this week (December 31st).

bjan suggested this:
1) Take a 40mm lens or longer ( e.g 50, 70, )
2) Use a 2.8 diafragma or larger ( e.g. 2.0 or 1.8 )
3) Take a pic from about 80 cms distance under daylight and the same pic with same diafragma and distance under artificial light. BOTH WITH AF on AF/S

Would a DA*16-50 be OK?
Is this all there is to it to find out if the K5 I am supposed to buy will have this problem?

The sales person also is aware that I will be "testing" it for the infamous sensor stains (two previously tested copies had the stain issue and were sent back).

I am hoping that this will be "it" this time.

Thanks in advance for any recommendation(s).

Cheers!

JP

janneman · 12-28-2010, 05:08 PM

Originally posted by bjan

. But our Japanes friends remain silent as if it is not their problem ! .

Tiger Woods, BP, Bankers....

Just look at what happened in the past 12 months and you realize how silly you look with public "I am sorry , I goofed" statements.

Even if Pentax came with a pucblic stament, wouldn't people say "Ah, they just do that to look good". Public appologies or acknowledgments will be looked upon "insincere" most of the time...

Tommot1965 · 12-28-2010, 07:58 PM

pentax dont need to say sorry...just a "we are working on a fix" will do me

mind you we aint alone...since I thought I might go for the nikon..that research has found Nikon are in the shit too with the D7000. and I reckon its got more problems than the K5

...

so I suppose we gotta suck it up if we want to be early adopters...sucks though, eh...

falconeye · 12-28-2010, 08:23 PM

Originally posted by deejjjaaaa

If I can hit the target which is a single black line on a white sheet of paper under the 100w rated tungsten bulb (~10-15" from bulb to the target) using my eye (20/20) + split prism + ome53 + fa50/1.4 then I kind of expect Safox-whatever to be able to do the same...

Can we please keep the church in the village?
(old German proverb. Sorry if it doesn't make sense in another language

)

This is a simple software bug. Software bugs happen and are easy enough to fix.

One way to see it's a software bug (read firmware) is that the K-5 doesn't even activate AF assist light and is pretty confident when locking wrong focus.

Zugzwang · 12-28-2010, 10:10 PM

Can we please keep the church in the village?
(old German proverb. Sorry if it doesn't make sense in another language )

This is a simple software bug. Software bugs happen and are easy enough to fix.

No offence, but I would like to hear that from Pentax rather than you to give me some comfort.

glanglois · 12-28-2010, 11:16 PM

Comfort will come with the update/fix.

In the meantime, I'll put off worrying. Falk is making the right point; AF is generally a software function.

Unless you can tell us a bit about the K-5 hardware arrangements re: long-wavelength light and AF?? I'm always eager to learn ...

jolepp · 12-29-2010, 01:18 AM

Originally posted by jpzk

...I am hoping someone would provide some "tips" on how to test the K5 for AF in dimmed Tungsten light when I go to the store on Friday this week (December 31st).
...

This would seem like a neat, pocketable method:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/126249-how-int...ml#post1307972

The best part of the above IMO is that you not only see if there is a problem but whether it is back/front focus. The DA 16-50 should show the symptoms (if any) clearly at 50mm, f=2.8 and a short distance (~0.5m). In general you'll want minimum DOF for testing, and that comes with large aperture/long FL/short subject distance.

I would assume that the issue this thread is about, that is, different focusing under low artifical light vs. daylight affects all K-5s, but you never know. Testing for FF/BF with the fast lenses you have makes sense in any case. This way, you might avoid sending in the body for adjustment and/or getting a lens body combo where you run out of adjustement range. If you have other fast lenses you could use in the circumstances consider bringing them too.

It seems that my Tamron 17-50 1:2.8 front focuses with the K-5 in any light and that I would need a bit more adjustment for best results: knowing what I know now I would have done well bringing that in when I went shopping. Luckily I also have a stained sensor, which should mean a replacement anyway ;-)

filorp · 12-29-2010, 01:52 AM

Originally posted by falconeye

This is a simple software bug.

its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it....

falconeye · 12-29-2010, 04:09 AM

Originally posted by filorp

its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it....

No, that's not the cause: the K-r doesn't have the light temperature sensor and still doesn't exhibit the same problem. But I agree, if the light temperature sensor gives completely wrong readings (at low light) then the fix would be to ignore it which would be a pitty. OTOH, the focus shift seems to be rather consistent. So, I don't think any hardware is broken. I rather suspect a real bug. I mean bug in the sense this word emerged.

Wheatfield · 12-29-2010, 05:14 AM

Originally posted by filorp

its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it....

The focus error appears to be independent of colour temperature.

12-28-2010, 05:05 PM	#276
jpzk Site Supporter Join Date: Jan 2009 Location: Québec Photos: Gallery \| Albums Posts: 8,251	Apologies to barge in on a very technical thread in which I have not much to offer "technically". I have just spent half an hour reading through the posts here (I am a slow reader) and I am hoping someone would provide some "tips" on how to test the K5 for AF in dimmed Tungsten light when I go to the store on Friday this week (December 31st). bjan suggested this: 1) Take a 40mm lens or longer ( e.g 50, 70, ) 2) Use a 2.8 diafragma or larger ( e.g. 2.0 or 1.8 ) 3) Take a pic from about 80 cms distance under daylight and the same pic with same diafragma and distance under artificial light. BOTH WITH AF on AF/S Would a DA16-50 be OK? Is this all there is to it to find out if the K5 I am supposed to buy will have this problem? The sales person also is aware that I will be "testing" it for the infamous sensor stains (two previously tested copies had the stain issue and were sent back). I am hoping that this will be "it" this time. Thanks in advance for any recommendation(s). Cheers! JP Last edited by jpzk; 12-28-2010 at 05:12 PM.*

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12-28-2010, 02:11 PM	#271
bjan Senior Member Join Date: Feb 2010 Posts: 116 Original Poster	Originally posted by Gimbal My main lens is a Sigma17-70 and the FF is most obvious (by far) at the 17mm end, a meter or so in error on a 2,5 meters distance is the norm. Things get more and more out of control I guess ! Hope PENTAX adresses the issue very quick as it gets worse the more people start looking into the matter. Hundreds of reactions in this forum and hundreds in German and other forums around the globe affirming the issue is not a simple issue anymore I suggest . But our Japanes friends remain silent as if it is not their problem ! If the problem ever gets solved I hope I served the situation with the start of several threads on the internet. I will step out a bit now because I might be seen as a troll by some and that would do the case no good as it is very serious but the issue can "float" on its own I assume after initiating. Thanks for all your input .

12-28-2010, 02:23 PM	#272
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	Originally posted by bjan Things get more and more out of control I guess nothing is getting out of control - I 'd say things are just not getting 1-2 magnitudes better in that very-very specific department (even the AF from Pentax in general is becoming better and better)... it is not a new problem - it is the old problem since *ist's (digital) days... and I just can't understand what is the problem to allow to have 2 sets of AF adjustments in firmware... you have AF adjustments already in place, it is already an acknowledgment that your AF is not perfect - so just make it better, make it 2 sets (for daylight and tungsten) and also make it like Olympus did - tunable for zooms @ wide, middle, long ends... we are not even asking to make it like Olympus did tunable per each AF point

12-28-2010, 02:53 PM	#273
jolepp Veteran Member Join Date: Oct 2010 Location: Finland Photos: Albums Posts: 3,196	Originally posted by deejjjaaaa ... and I just can't understand what is the problem to allow to have 2 sets of AF adjustments in firmware... I understood from a previous post that this sort of thing can in fact be done with the K-5 user modes?

12-28-2010, 03:06 PM	#274
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,986	Originally posted by bjan Things get more and more out of control I guess ! Hope PENTAX adresses the issue very quick as it gets worse the more people start looking into the matter. Hundreds of reactions in this forum and hundreds in German and other forums around the globe affirming the issue is not a simple issue anymore I suggest . But our Japanes friends remain silent as if it is not their problem ! If the problem ever gets solved I hope I served the situation with the start of several threads on the internet. I will step out a bit now because I might be seen as a troll by some and that would do the case no good as it is very serious but the issue can "float" on its own I assume after initiating. Thanks for all your input . Ahh, trying to drive up the hysteria meter again I see.

12-28-2010, 03:18 PM	#275
Malake New Member Join Date: Nov 2010 Posts: 12	Quote: My main lens is a Sigma17-70 and the FF is most obvious (by far) at the 17mm end Same with my combo Nikon D90+Sigma 17-70, even in good light.

12-28-2010, 05:08 PM	#277
janneman Veteran Member Join Date: Sep 2006 Location: Netherlands Photos: Gallery Posts: 908	Originally posted by bjan . But our Japanes friends remain silent as if it is not their problem ! . Tiger Woods, BP, Bankers.... Just look at what happened in the past 12 months and you realize how silly you look with public "I am sorry , I goofed" statements. Even if Pentax came with a pucblic stament, wouldn't people say "Ah, they just do that to look good". Public appologies or acknowledgments will be looked upon "insincere" most of the time...

12-28-2010, 07:58 PM	#278
Tommot1965 Veteran Member Join Date: Sep 2010 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 1,026	pentax dont need to say sorry...just a "we are working on a fix" will do me mind you we aint alone...since I thought I might go for the nikon..that research has found Nikon are in the shit too with the D7000. and I reckon its got more problems than the K5 ... so I suppose we gotta suck it up if we want to be early adopters...sucks though, eh...

12-28-2010, 08:23 PM	#279
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by deejjjaaaa If I can hit the target which is a single black line on a white sheet of paper under the 100w rated tungsten bulb (~10-15" from bulb to the target) using my eye (20/20) + split prism + ome53 + fa50/1.4 then I kind of expect Safox-whatever to be able to do the same... Can we please keep the church in the village? (old German proverb. Sorry if it doesn't make sense in another language ) This is a simple software bug. Software bugs happen and are easy enough to fix. One way to see it's a software bug (read firmware) is that the K-5 doesn't even activate AF assist light and is pretty confident when locking wrong focus.

12-28-2010, 10:10 PM	#280
Zugzwang Junior Member Join Date: Jun 2007 Location: Canada Posts: 49	Can we please keep the church in the village? (old German proverb. Sorry if it doesn't make sense in another language ) This is a simple software bug. Software bugs happen and are easy enough to fix. No offence, but I would like to hear that from Pentax rather than you to give me some comfort.

12-28-2010, 11:16 PM	#281
glanglois Veteran Member Join Date: Aug 2007 Location: Madison, Wis., USA Posts: 1,506	Comfort will come with the update/fix. In the meantime, I'll put off worrying. Falk is making the right point; AF is generally a software function. Unless you can tell us a bit about the K-5 hardware arrangements re: long-wavelength light and AF?? I'm always eager to learn ...

12-29-2010, 01:18 AM	#282
jolepp Veteran Member Join Date: Oct 2010 Location: Finland Photos: Albums Posts: 3,196	Originally posted by jpzk ...I am hoping someone would provide some "tips" on how to test the K5 for AF in dimmed Tungsten light when I go to the store on Friday this week (December 31st). ... This would seem like a neat, pocketable method: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/126249-how-int...ml#post1307972 The best part of the above IMO is that you not only see if there is a problem but whether it is back/front focus. The DA 16-50 should show the symptoms (if any) clearly at 50mm, f=2.8 and a short distance (~0.5m). In general you'll want minimum DOF for testing, and that comes with large aperture/long FL/short subject distance. I would assume that the issue this thread is about, that is, different focusing under low artifical light vs. daylight affects all K-5s, but you never know. Testing for FF/BF with the fast lenses you have makes sense in any case. This way, you might avoid sending in the body for adjustment and/or getting a lens body combo where you run out of adjustement range. If you have other fast lenses you could use in the circumstances consider bringing them too. It seems that my Tamron 17-50 1:2.8 front focuses with the K-5 in any light and that I would need a bit more adjustment for best results: knowing what I know now I would have done well bringing that in when I went shopping. Luckily I also have a stained sensor, which should mean a replacement anyway ;-)

12-29-2010, 01:52 AM	#283
filorp Veteran Member Join Date: Jun 2008 Location: Aberdeen Scotland Photos: Gallery \| Albums Posts: 398	Originally posted by falconeye This is a simple software bug. its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it....

12-29-2010, 04:09 AM	#284
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by filorp its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it.... No, that's not the cause: the K-r doesn't have the light temperature sensor and still doesn't exhibit the same problem. But I agree, if the light temperature sensor gives completely wrong readings (at low light) then the fix would be to ignore it which would be a pitty. OTOH, the focus shift seems to be rather consistent. So, I don't think any hardware is broken. I rather suspect a real bug. I mean bug in the sense this word emerged.

12-29-2010, 05:14 AM	#285
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,986	Originally posted by filorp its not this simple... there is double af sensor one for general focusing second for light temperature compensation - the last one doesnt seames to work, it can be faulty or the software doesnt know haw to read from it.... The focus error appears to be independent of colour temperature.