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12-11-2008, 02:10 PM   #16
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yes there is the body camera temperature in exif

i have some pics at -14 excellent
some at -5 with banding
i have not notice the problem with temperature above 10c
i can see with thorough examinations of some shots that the problem can appear more or less obviously, sometimes the banding is there but less apparent, sometimes it is excessively there.

it's not that the camera warms in my hand
perhaps the sensor or electronics needs to heat up and it will with usage (i.e. after one shot, the eletronics has heat up)
that's why someone reported the problem is less apparent with liveview on (the sensor heats up)
but it is definitely a design problem, it should heat up by itself and be ready to shoot. plus its not all k20 that are subject to the problem.
and that's more mysterious. so their might be a production problem here

12-11-2008, 04:17 PM   #17
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QuoteOriginally posted by phler2 Quote
Hi,
some time ago, i posted on this subject
https://www.pentaxforums.com/forums/pentax-dslr-discussion/24253-k20d-dithering-problem.html

i returned my k20 to pentax to have it checked
they returned it to me saying it was working and they couldnt reproduce the problem

i took it out last weekend, and it did it again.
now, I thought it was because of the cold temperature
however last w.e. it was only -5 cel
i do not expect the k20 to not work at that temperature

i'm left wondering if it is not a firmware problem at some point (reading the sensor or converting raw to jpeg) because of the very regular vertical (in landascape that is) stripes all over the image

so now what can i do? is there any pentax engineer i could contact directly to try te debug and sort that out?

or would i have to sell everything on ebay and move on to canon niikon or sony?
Note the following offical Pentax specification for the K20D operating temperature pulled from the PentaxUSA website:

"Specifications: Body dimensions (W x H x D) - 5.6 x 4.0 x 2.76; Body weight (without battery or removable memory) - 25.2 oz; Loaded and ready - 28.2 oz; Construction material(s) - Reinforced plastic polymer shell surrounding a rugged stainless steel chassis; Operating temperature - 32-104 degrees F"

32 F = 0 cel. -5 cel is well below the designed operating range of the camera.

0 cel seems to be the limit for the Nikon D300 as well, and the Canon 50D is also listed as 32 - 104F.

If you know anything about electronics, you know that there is a reason that all of the cameras have similar ratings.

Ray
12-11-2008, 07:36 PM   #18
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Hi,

I happen to be an engineer in electronics. i'm not an expert in camera electronics as i do not work for a camera company.
however, i understand clearly why they advise to use it above 0deg
and it is mostly for battery purposes
it can also be for other non electronic related reasons (e.g. condensation on lenses)
in fact, low temperature, if voltage can be maintained by the battery (which is not guaranteed, but if camera powers up than it is fine) should yield less noise which is mostly caused by thermal noise in the electronics.
now, there is certainly a need for the sensor or the electronics to initialize which is not done correctly and that would explain why first shots are bad and following ok.

that said, i have some pictures with reported camera temperature of 9c !
and come on -5 is not well below 0

that still wouldn't explain why it happens for some k20d and not for others ( see Re: K20D, don't like cold temperatures?: Pentax SLR Talk Forum: Digital Photography Review) . and it still wouldn't explain why some shots are ok even with camera temperature reported at -14. and don't tell me that the camera's sensor would heat itself in half a second from -14 to above 0 in that case.

so if the problem is triggered with cold temperatures, it is not the main reason, and i still believe pentax engineers and marketing people shouldn't hide behind this pretension that the camera is not made to work at these temperature (and remember the problems happens with temps above 0)

otherwise why would they sell in quebec city? it's below 0c 6 month a year

moreover, why does the canon 50D doesn't have this kind of bad reports of electronics below 0. if pentax wants me to advertise every potential buyer not to by pentax because they live in quebec. well wouldn't that be stupid

so please pentax, be nice, try to sort out the problem, make me believe i can still have faith in my k20d and in the brand name of pentax

please pentax? it's a good camera you got there, don't spoil it with bad after sell service.
12-11-2008, 09:36 PM   #19
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QuoteQuote:
One of the rep told me that if I send the camera until 3 times and they can't fix it,
that's when they'll replace my camera.

This is the true application of the "lemon law", originally from the automotive industry. The manufacturer gets 3 tries to fix the SAME problem.

12-12-2008, 01:19 AM   #20
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QuoteOriginally posted by phler2 Quote
Hi,

I happen to be an engineer in electronics. i'm not an expert in camera electronics as i do not work for a camera company.
however, i understand clearly why they advise to use it above 0deg
and it is mostly for battery purposes
it can also be for other non electronic related reasons (e.g. condensation on lenses)
in fact, low temperature, if voltage can be maintained by the battery (which is not guaranteed, but if camera powers up than it is fine) should yield less noise which is mostly caused by thermal noise in the electronics.
now, there is certainly a need for the sensor or the electronics to initialize which is not done correctly and that would explain why first shots are bad and following ok.

that said, i have some pictures with reported camera temperature of 9c !
and come on -5 is not well below 0

that still wouldn't explain why it happens for some k20d and not for others ( see Re: K20D, don't like cold temperatures?: Pentax SLR Talk Forum: Digital Photography Review) . and it still wouldn't explain why some shots are ok even with camera temperature reported at -14. and don't tell me that the camera's sensor would heat itself in half a second from -14 to above 0 in that case.

so if the problem is triggered with cold temperatures, it is not the main reason, and i still believe pentax engineers and marketing people shouldn't hide behind this pretension that the camera is not made to work at these temperature (and remember the problems happens with temps above 0)

otherwise why would they sell in quebec city? it's below 0c 6 month a year

moreover, why does the canon 50D doesn't have this kind of bad reports of electronics below 0. if pentax wants me to advertise every potential buyer not to by pentax because they live in quebec. well wouldn't that be stupid

so please pentax, be nice, try to sort out the problem, make me believe i can still have faith in my k20d and in the brand name of pentax

please pentax? it's a good camera you got there, don't spoil it with bad after sell service.

Do you run the proper anti-freeze in your car in the winter?

Why? Probably because the SPECIFICATIONS for your car, as developed by the designers, tell you to do so or the car may not work correctly.

Like it or not, the product has a very well defined spec. If it does not work properly outside of that spec. well, duh is all I can say.

Ray
12-12-2008, 04:05 AM   #21
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I absolutley shure it has nothing to do with low temperature. The banding on my first body appeared indoors and outdoors at temperatures around 20C.
And the body had never been exposed to cold temperatures.
12-12-2008, 07:14 AM   #22
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@Ray Pulley

as i said, the banding has mostly happen in cold weather
but not only
ok?

plus, the question is more about understanding what is happening so that it can actually be corrected. that's what a true engineer would do and not just hide behind an excuse .

and then again, if pentax engineer don't care. than they don't care for their own product. and so what would it be worth buying.

i'm just starting to wonder if it was worth it to buy pentax. i went for it because i wanted to encourage a company well behind competitors and because i thought they had a good product. maybe not in fact

and please, anti-freeze in a car is not electronics
are you engineer? and can you explain thoroughly why the electronics would not work below 0c?
as i said, it is mostly a question of battery, which is chemical. and if the voltage is fine on the battery, than the camera should work. if not, than the fact that banding appears in cold weather might be a production defect such as a bad welding. and that's a defect which should be corrected.

lets try to be constructive here, i'm not the only one having the problem
and if it didn't happen at 25c, it still is a problem that should be examined thoroughly and corrected.
don't you think so?
12-12-2008, 08:14 AM   #23
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Hi,

i invite you people to have a look at my last post on dpreview

it clearly shows there exist a problem with the camera, and that is not a question of cold weather
it is either a production defect or even a design problem

Re: K20D, don't like cold temperatures?: Pentax SLR Talk Forum: Digital Photography Review

12-12-2008, 09:01 AM   #24
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QuoteOriginally posted by phler2 Quote
i'm just starting to wonder if it was worth it to buy pentax. i went for it because i wanted to encourage a company well behind competitors and because i thought they had a good product. maybe not in fact

and please, anti-freeze in a car is not electronics
are you engineer? and can you explain thoroughly why the electronics would not work below 0c?
I understand your disapointment (and I'm disapointed too) but if you think the grass is greener on the other side, think twice. Now I should say that this issue is only with the K20D. I never ever had this kind of problems with K10D after more than 20,000 actuations in all kind of conditions.

Some people are suspecting it's related to temperature because it happened mostly in these conditions. As the winter is now coming, we will see if more people report this problem and if it's the case how Pentax will deal with it. This maybe fixed with a new firmware because the pattern is extremely regular. If we can find to reproduce the problem all the time, it would be easier for the Pentax engineers to find a solution. Let's try to be positive, no whinning will help.
12-12-2008, 09:48 AM   #25
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i agree, i was being somewhat negative because my seller had just talked to a pentax responsible who was not at all cooperating (actually he was being an idiot, that's only on person though). but that is typically the kind of behavior that is not helpful and that makes consumers run away

however, if the problem can be corrected by software by a filter
this still remains a hack
the problem does not appear for some k20, so it means it is a hardware problem. and that should be corrected.
12-14-2008, 03:20 PM   #26
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QuoteOriginally posted by Ray Pulley Quote
Do you run the proper anti-freeze in your car in the winter?

Why? Probably because the SPECIFICATIONS for your car, as developed by the designers, tell you to do so or the car may not work correctly.

Like it or not, the product has a very well defined spec. If it does not work properly outside of that spec. well, duh is all I can say.

Ray
Well, that is a pretty inconsiderate and non-nonsensical remark!

Your anti-freeze analogy doesn't even make sense.

I have a electronics engineering education (not what I do now though) and I concur with what Phler2 stated. The specs are primarily about preserving the battery's power and issues of frost build up and subsequent condensation (which is alleviated by properly acclimatizing your equipment in both directions).

Like Phler2 also stated, aside from the above stated issues, the cold is actually good for electronics because heat results in digital noise. Astronomers have been cooling imaging sensors to sub-zero temperatures since the beginning, in order to obtain the best long exposure photos.

I haven't exposed my K20D to low temperatures yet but I can tell you right now, if I see this banding problem, I am going to be very angry and I will do everything in my ability to get this problem solved or my money back! I already got burned with the *ist camera and this will be the 'last straw'.

BTW, Ray the Canon xxD series of cameras are used with great success in cold weather (way below Canon's recommended temperature specifications), as such their cameras are a hit among wildlife photographers and astronomers. Are you defending Pentax by suggesting that the K20D is a lessor camera than Canon's equivalent?
12-14-2008, 03:34 PM   #27
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QuoteOriginally posted by phler2 Quote
i agree, i was being somewhat negative because my seller had just talked to a pentax responsible who was not at all cooperating (actually he was being an idiot, that's only on person though). but that is typically the kind of behavior that is not helpful and that makes consumers run away

however, if the problem can be corrected by software by a filter
this still remains a hack
the problem does not appear for some k20, so it means it is a hardware problem. and that should be corrected.
I am certainly not privy to the design of the K20D electronics but a fix is not necessarily a type of imaging filter algorithm (which would be extremely complex). Rather, it is possible that Pentax could modify the way in which the CMOS sensor or associated electronics are powered/controlled under certain conditions (like temperature). Such a firmware modification might be enough to eliminate the banding.

Pentax won't budge if only 1 or 2 people are complaining.... but if this is systemic, I am sure they will have to do something about this. No offence, selfishly I am hoping that my K20D is not affected. I am in Vancouver where we have unprecedented LOW temperatures. This is the perfect opportunity to test the K20D in cold weather conditions. I will try to get out tomorrow morning. I will also test the K20D with both the old firmware 1.00 and the newest firmware 1.xx (whatever).

In the meantime, I will follow both your threads on this issue and report back as soon as possible.
12-14-2008, 07:30 PM   #28
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Hi everyone

i am glad to see people are concerned here and are trying to sort things out.

i have been looking at technical aspects of pictures generated by the k20, as you might have seen on my post on dpreview (see link a few post higher in this thread)

i continued exploring. and there is bad news here : yes some images are very badly affected by the problem of this noise banding. but in fact pretty much all images are. let me explain here. it is not a noise problem :
it is a parasitic signal, or a signal interfering, not a noise : it is an horizontal high frequency (yielding vertical bands) and it is present even when your eyes don't see it on most pictures.

given the systematic (all the surface of the image is affected) vertical aspect and i suspect it could have to do with the electronics in the reading of the sensor. that said i don't know how the sensors is read put probably by scanning it horizontally.

a very simple fft reveals high power level at 1/2 the maximum Nyquist frequency which is definitely not noise. i can clearly observe it at different iso settings at and it is not only on the first shots of a series of shots that is affected (even thought it is the case for images that are heavily affected )

i would like your help here, if you have a k20d that has not shown to be problematic, can you send me some shots raw+jpegs
take shots of walls with plain colors or something like that, at different iso/exposure time.
please sent the data to l e r o u x 0 0 - a t - y a h o o - d o t - fr
i'll give you some feedback.

thanks

P
12-14-2008, 07:31 PM   #29
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QuoteOriginally posted by pentaxmz Quote
Well, that is a pretty inconsiderate and non-nonsensical remark!

Your anti-freeze analogy doesn't even make sense.

I have a electronics engineering education (not what I do now though) and I concur with what Phler2 stated. The specs are primarily about preserving the battery's power and issues of frost build up and subsequent condensation (which is alleviated by properly acclimatizing your equipment in both directions).

Like Phler2 also stated, aside from the above stated issues, the cold is actually good for electronics because heat results in digital noise. Astronomers have been cooling imaging sensors to sub-zero temperatures since the beginning, in order to obtain the best long exposure photos.

I haven't exposed my K20D to low temperatures yet but I can tell you right now, if I see this banding problem, I am going to be very angry and I will do everything in my ability to get this problem solved or my money back! I already got burned with the *ist camera and this will be the 'last straw'.

BTW, Ray the Canon xxD series of cameras are used with great success in cold weather (way below Canon's recommended temperature specifications), as such their cameras are a hit among wildlife photographers and astronomers. Are you defending Pentax by suggesting that the K20D is a lessor camera than Canon's equivalent?

You missed the point:

Everything has a set of operating conditions and specifications, your car and your camera. Use them outside of these parametrs at your own risk, and there are no promises that anything will work correctly, and in almost all cases you would void your warranty by doing so. BTW, that includes Canon gear. Go ahead and try to get Canon to fix your camera under warranty if it behaves incorrectly when used outside of the specifications.

Electronics defiintely behave differently above and below the specified operating ranges and all electronics have such specs. Of course folks like Intel must also be less smart than you are because they specify 0 - 55C operating range on the Motherboards they make. Maybe that is also just about battery life, eh?

Cameras have shutters, aperture mechanisms, plastic parts, shake reduction assemblies, gears and other mechanical assemblies that all have specified operating ranges. Dimensions and sizes of various precision parts change with temperature, as do the various physical properties of the materials used in the product. The design has to take all of this into account and set limits upon the operating range inside of which the cameras is designed to work.

As for Engineers, well let's just say that I have been manufacturing electronic assemblies designed by EE's for more than 30 years (which currently includes specialized digital cameras) and what I have learned about engineers is that there are some good ones, and many bad ones, but I have yet to meet one that would say that the specified operating conditions of the equipment they designed is meaningless. Most are also clueless about most things mechanical, just as you two appear to be.

Of course, since this is the internet, you two electronic experts clearly know better than the design engineers at Hoya/Pentax......

Ray
12-14-2008, 07:36 PM   #30
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QuoteOriginally posted by pentaxmz Quote
I am certainly not privy to the design of the K20D electronics but a fix is not necessarily a type of imaging filter algorithm (which would be extremely complex).
well in fact given the problem is not noise, but a signal that is rather very specific (a sinus at 1/2 the nyquist freq), it could be removed quite easily with a notch filter and some adaptation parameter evaluated on the image.
but still. i don't want my dslr to have to use *eye glasses* to correct its perception problems..
any pentax engineer willing to give us some info here on the origin of that signal? because given its pervasiveness i presume you are aware of it and perhaps have been for a long time?
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