Stain Question

TOUGEFC · 02-24-2011, 01:06 AM

Another question about the stains, yes I know how to test for them and what they look like. But I have a question before I buy....
FWIW I will be testing the K-5 in store before purchase.

If I find a stain free K-5 after in store testing, will it remain stain free, or will/can these stains show up later on after the camera has been used for a while?

JeffJS · 02-24-2011, 01:23 AM

Maybe Yes, Maybe No.

These were all done when my K5 was only a week old (to me). There are full stop down photos (f22 etc) in each set.

Index of /Photos/50mmShootout

The Stain didn't appear until Mid January. It's a crapshoot at this point as far as I'm concerned. If my replacement camera exhibits the stains within the warranty period again, they will replace (or repair) the camera, Again.

TOUGEFC · 02-24-2011, 01:41 AM

Ok thanks Jeff, i guess its a gamble then.
Also will stains show up on photos at aperture's f/5.6 and bigger?

30v iPentax · 02-24-2011, 02:16 AM

Sony kenno on aina sony kenno.

TOUGEFC · 02-24-2011, 02:36 AM

Originally posted by 30v iPentax

Sony kenno on aina sony kenno.

What does that have to do with my question?

JeffJS · 02-24-2011, 06:57 AM

Originally posted by TOUGEFC

Ok thanks Jeff, i guess its a gamble then.
Also will stains show up on photos at aperture's f/5.6 and bigger?

Not in my experience. I imagine if I waited long enough they may have gotten worse and showed up but mine were discovered around the f16 range (k28mm f2.0). The theory is that they were there from the start but using Live View enough cooked them in. I tend to believe that theory because I know for a fact that the inside of my camera was never exposed to anything that would have caused this..

Just like everyone elses, pretty much dead center of the picture.

bymy141 · 02-24-2011, 11:52 AM

Originally posted by JeffJS

Maybe Yes, Maybe No.

These were all done when my K5 was only a week old (to me). There are full stop down photos (f22 etc) in each set.

Index of /Photos/50mmShootout

The Stain didn't appear until Mid January. It's a crapshoot at this point as far as I'm concerned. If my replacement camera exhibits the stains within the warranty period again, they will replace (or repair) the camera, Again.

I don't understand.
These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters.
How can new stains get there after manufacturing?
I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses.
Or am I misunderstanding your reply?

- Bert

dgaies · 02-24-2011, 11:59 AM

Originally posted by bymy141

I don't understand.
These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters.
How can new stains get there after manufacturing?
I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses.
Or am I misunderstanding your reply?

- Bert

I believe the current thought it that yes, the stains are between the AA filter and the sensor. However, based on the fact that the stains don't always appear right away and/or grow in number, intensity and size, there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken.

JeffJS · 02-24-2011, 01:51 PM

Originally posted by bymy141

I don't understand.
These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters.
How can new stains get there after manufacturing?
I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses.
Or am I misunderstanding your reply?

- Bert

I didn't say it wasn't there. I said it didn't appear in the photos right away. If it had Never appeared in the photos, I would not have gone a full month without my K5. Trust me, I know what dust looks like and the photo I show above has nothing to do with dust.

Originally posted by dgaies

I believe the current thought it that yes, the stains are between the AA filter and the sensor. However, based on the fact that the stains don't always appear right away and/or grow in number, intensity and size, there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken.

^^^^^^^

What he said.

ve2vfd · 02-24-2011, 01:55 PM

Originally posted by dgaies

there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken.

I doubt we'll ever get any explanations from Pentax, but up to now thats the theory I personally think is most likely.

Pat

bobmaxja · 02-24-2011, 09:18 PM

The one wo got stain was the early production . Whit the new production lately , nobody have complaint and I do not expect issue long term . Stay away from lower serial #

cem.kumuk · 02-25-2011, 02:58 AM

If I'm not wrong you may not explore a stain when you test the brand new camera at dealer's place. Because some stains are becoming visible after using the camera for sometime, especially after making long exposure shots. At least like mine. It's said to be some parts of the layer on the sensor is burnt during long exposure depending on the increasing sensor heat and these seem as stains.

philippe · 02-25-2011, 03:18 AM

Originally posted by bobmaxja

The one wo got stain was the early production . Whit the new production lately , nobody have complaint and I do not expect issue long term . Stay away from lower serial #

Perhaps I missed it, but from which serial number on is 'it' safe?

jolepp · 02-25-2011, 04:46 AM

The conjecture is that drops of solvent used in the manufacture trapped inside the sensor assembly eventually evaporate and leave behind a residue (=stain). This is based on the stament from Pentax Germany that was posted here; this mentioned "volatile material", assuming solvent from the manufacturing process is guesswork of course. This would explain how some units develop stains as that "volatile material" evaporates (because the sensor draws current and gets warm in use).

jolepp · 02-25-2011, 04:52 AM

Originally posted by philippe

Perhaps I missed it, but from which serial number on is 'it' safe?

Units made since week 50/2010 should be ok per Pentax Germany statement, the manufacture date can be found in the image files with PhotoMe or somesuch. (Apparenty the serial numbers do not correspond strictly to the manufacture date).

02-24-2011, 01:06 AM	#1
TOUGEFC Veteran Member Join Date: Nov 2009 Location: Brisbane Photos: Gallery Posts: 3,561	Stain Question Another question about the stains, yes I know how to test for them and what they look like. But I have a question before I buy.... FWIW I will be testing the K-5 in store before purchase. If I find a stain free K-5 after in store testing, will it remain stain free, or will/can these stains show up later on after the camera has been used for a while?

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02-24-2011, 01:23 AM	#2
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Maybe Yes, Maybe No. These were all done when my K5 was only a week old (to me). There are full stop down photos (f22 etc) in each set. Index of /Photos/50mmShootout The Stain didn't appear until Mid January. It's a crapshoot at this point as far as I'm concerned. If my replacement camera exhibits the stains within the warranty period again, they will replace (or repair) the camera, Again.

02-24-2011, 01:41 AM	#3
TOUGEFC Veteran Member Join Date: Nov 2009 Location: Brisbane Photos: Gallery Posts: 3,561 Original Poster	Ok thanks Jeff, i guess its a gamble then. Also will stains show up on photos at aperture's f/5.6 and bigger?

02-24-2011, 02:16 AM	#4
30v iPentax Inactive Account Join Date: Apr 2010 Location: Suomi , Finland Posts: 368	Sony kenno on aina sony kenno.

02-24-2011, 02:36 AM	#5
TOUGEFC Veteran Member Join Date: Nov 2009 Location: Brisbane Photos: Gallery Posts: 3,561 Original Poster	Originally posted by 30v iPentax Sony kenno on aina sony kenno. What does that have to do with my question?

02-24-2011, 06:57 AM	#6
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Originally posted by TOUGEFC Ok thanks Jeff, i guess its a gamble then. Also will stains show up on photos at aperture's f/5.6 and bigger? Not in my experience. I imagine if I waited long enough they may have gotten worse and showed up but mine were discovered around the f16 range (k28mm f2.0). The theory is that they were there from the start but using Live View enough cooked them in. I tend to believe that theory because I know for a fact that the inside of my camera was never exposed to anything that would have caused this.. Just like everyone elses, pretty much dead center of the picture.

02-24-2011, 11:52 AM	#7
bymy141 Veteran Member Join Date: Aug 2007 Photos: Gallery Posts: 1,563	Originally posted by JeffJS Maybe Yes, Maybe No. These were all done when my K5 was only a week old (to me). There are full stop down photos (f22 etc) in each set. Index of /Photos/50mmShootout The Stain didn't appear until Mid January. It's a crapshoot at this point as far as I'm concerned. If my replacement camera exhibits the stains within the warranty period again, they will replace (or repair) the camera, Again. I don't understand. These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters. How can new stains get there after manufacturing? I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses. Or am I misunderstanding your reply? - Bert

02-24-2011, 11:59 AM	#8
dgaies Veteran Member Join Date: Oct 2009 Location: Maryland / Washington DC Posts: 3,917	Originally posted by bymy141 I don't understand. These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters. How can new stains get there after manufacturing? I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses. Or am I misunderstanding your reply? - Bert I believe the current thought it that yes, the stains are between the AA filter and the sensor. However, based on the fact that the stains don't always appear right away and/or grow in number, intensity and size, there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken.

02-24-2011, 01:51 PM	#9
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Originally posted by bymy141 I don't understand. These stains are on the bottom surface of the AA filter and got there because of some solvent issue producing the filters. How can new stains get there after manufacturing? I guess the new stains you are discovering are "normal" dust spots, a risk of changing lenses. Or am I misunderstanding your reply? - Bert I didn't say it wasn't there. I said it didn't appear in the photos right away. If it had Never appeared in the photos, I would not have gone a full month without my K5. Trust me, I know what dust looks like and the photo I show above has nothing to do with dust. Originally posted by dgaies I believe the current thought it that yes, the stains are between the AA filter and the sensor. However, based on the fact that the stains don't always appear right away and/or grow in number, intensity and size, there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken. ^^^^^^^ What he said.

02-24-2011, 01:55 PM	#10
ve2vfd Veteran Member Join Date: Aug 2007 Location: Montreal, Canada Photos: Gallery Posts: 2,433	Originally posted by dgaies there is a theory that while the solvent is present from the start, the heat the sensor generates during use can cause the stains to appear/enlarge/darken. I doubt we'll ever get any explanations from Pentax, but up to now thats the theory I personally think is most likely. Pat

02-24-2011, 09:18 PM	#11
bobmaxja Veteran Member Join Date: Mar 2010 Location: Laval, Quebec Canada Posts: 2,171	The one wo got stain was the early production . Whit the new production lately , nobody have complaint and I do not expect issue long term . Stay away from lower serial #

02-25-2011, 02:58 AM	#12
cem.kumuk Senior Member Join Date: Jan 2010 Location: Istanbul Photos: Gallery Posts: 241	If I'm not wrong you may not explore a stain when you test the brand new camera at dealer's place. Because some stains are becoming visible after using the camera for sometime, especially after making long exposure shots. At least like mine. It's said to be some parts of the layer on the sensor is burnt during long exposure depending on the increasing sensor heat and these seem as stains.

02-25-2011, 03:18 AM	#13
philippe Veteran Member Join Date: Apr 2008 Location: Flanders Fields Posts: 463	Originally posted by bobmaxja The one wo got stain was the early production . Whit the new production lately , nobody have complaint and I do not expect issue long term . Stay away from lower serial # Perhaps I missed it, but from which serial number on is 'it' safe?

02-25-2011, 04:46 AM	#14
jolepp Veteran Member Join Date: Oct 2010 Location: Finland Photos: Albums Posts: 3,196	The conjecture is that drops of solvent used in the manufacture trapped inside the sensor assembly eventually evaporate and leave behind a residue (=stain). This is based on the stament from Pentax Germany that was posted here; this mentioned "volatile material", assuming solvent from the manufacturing process is guesswork of course. This would explain how some units develop stains as that "volatile material" evaporates (because the sensor draws current and gets warm in use).

02-25-2011, 04:52 AM	#15
jolepp Veteran Member Join Date: Oct 2010 Location: Finland Photos: Albums Posts: 3,196	Originally posted by philippe Perhaps I missed it, but from which serial number on is 'it' safe? Units made since week 50/2010 should be ok per Pentax Germany statement, the manufacture date can be found in the image files with PhotoMe or somesuch. (Apparenty the serial numbers do not correspond strictly to the manufacture date).