hot pixels?

*laissezfaire* · 10-01-2008, 09:23 PM

I was doing some comparisons of the 18-55 kit lens vs. 50mm 1.4 vs. 50-135 2.8 to see how they performed at 50mm 5.6 800ISO (the kit lens looks a bit smeared at 100% crop versus the other two which are close, but the 50-135 may have an ever so slight edge)... well it was all handheld, so not really a "test".

I got distracted by the following hot spots (there's four total that I noticed) in every single picture, then I went back and noticed spots on any dark background with higher ISO settings.

Are these permanent hot pixels or consistent noise at ISO800? Is this covered under warranty?

I tried the StarZen dead pixel program and it came back with lots of positive dead pixels, but I'm not sure if I know how to use that.

*Canada_Rockies* · 10-01-2008, 09:38 PM

If you have the k20d, you can map them out yourself. I have the k10d, and have to map them out in post processing. No $$$ to pick up the k20d here, unfortunately.

*laissezfaire* · 10-01-2008, 09:54 PM

Originally Posted by Canada_Rockies

If you have the k20d, you can map them out yourself. I have the k10d, and have to map them out in post processing. No $$$ to pick up the k20d here, unfortunately.

I did a bit more research... it appears this is a common problem. Here's what was suggested by some others. Has anyone here had experience with this?

"I'd certainly have the issue addressed under warranty, as such pixel
problems are covered by Nikon.

It would be very unusual for them to fix it by replacing the sensor,
however. This is typically done only if there are big clusters or rows of
bad pixels. If there are just random stuck or hot pixels, what they would
typically do is re-map the sensor, wherein they identify the pixels and
program the camera to have that area of the sensor display an average of
some of the surrounding pixels. Note that this is what your image processing
software does, but you can get Nikon to do it in-camera instead, which would
seem to me to be more convenient.

Given the number of pixels present in an APS-sized sensor (6 million in this
case) it is unlikely (impossible?) to cost-effectively manufacture a sensor
with NO bad pixels. As a result, each camera is "mapped" in this way as part
of the manufacturing process. With time and age, it is typical for a camera
to develop more such bad pixels. One way to deal with it is in your image
processing software, another is to re-map the sensor."

*Canada_Rockies* · 10-01-2008, 09:58 PM

I just did a quick Google search "Pentax k20d hot pixels" , and found that the hot pixel mapping is in the latest firmware update. Download and install and you can map them out.

cpopham · 10-02-2008, 02:41 AM

I have the same 'problem' with my K100D super as well. Mine manifests as two full-bright green pixels at ISO 1600+, and sometimes at lower ISO during longer exposures.

Often it is there, sometimes it is not. It doesn't really bother me before I tend to shoot RAW, and raw processors take it out.

I recall reading somewhere that you can have a dead pixel mapping performed under warranty.

*borno* · 10-02-2008, 03:54 AM

my k100super had a few and one right in the middle in the upper third, since the raw converter I use doesn't remove them, I sent it in with a reverse print of the spots and they mapped it out. It was covered under warranty. My k10d has a few but onlt at higher iso and I'm not worried about it. hope this helps

RiceHigh · 10-02-2008, 04:36 AM

Originally Posted by laissezfaire

Are these permanent hot pixels or consistent noise at ISO800? Is this covered under warranty?

This issue has been known for long and according to what DPR technical writers reported, the hot pixels are still visible even with the latest firmware which they waited for quite a while until they finished up their final review report:-

RiceHigh's Pentax Blog: K20D is Still "Hot" with Firmware 1.01

You are not alone. Actually, Steve's previous K20D review shown those clearly:-

RiceHigh's Pentax Blog: K20D Hot Pixels Issue Verified at Steves Digicams

I tried the StarZen dead pixel program and it came back with lots of positive dead pixels, but I'm not sure if I know how to use that.

Yes, the dead pixel detection program detects and reported all the mapped out pixels by the camera, i.e., deal pixels.

You can use the K20D's special and unique custom function for ruling out more hot pixels which will never detect light then. Do note as hot pixels are appearing more or less randomly and once you mapped / ruled out the pixels, there is no way to reset the mapping table. So, eventually, the user will have more and more pixels disabled in the end, when used over time and using the custom function more frequently. As this Polish reviewer pointed out, the worse case is that the whole sensor could be ruled out! Details as documented below:

RiceHigh's Pentax Blog: Issue of Hot/Dead Pixels of the K20D

This hot sensor issue is actually annoying. It just looks like a hardware issue to me afterall. I think unless Samsung and Pentax could resolve this issue by updating the design (possibly not able to be tackled with firmware update as they have tried that but proved to be failed by DPR), I would not recommend anyone to get the K20D.

*laissezfaire* · 10-02-2008, 06:53 AM

did more research, it's in every type of camera.

Hot Pixels

RiceHigh · 10-02-2008, 07:05 AM

Originally Posted by laissezfaire

did more research, it's in every type of camera.

Hot Pixels

Hot pixels exist in every digital camera but the K20D has been regarded as the "DSLRs with most visible hot pixels *ever seen* by the DPR.

In fact, the K20D cannot have the option of turning off the long exposure NR (aka dark frame subtraction), which just says it all how noisy and hot the sensor is.

P.S. THe K20D is the only Pentax DSLR or the only DSLR I know that cannot turn off the dark frame subtraction for long time exposure.

YJD · 10-02-2008, 07:19 AM

I have the same problem with my K100D Super, I'm thinking sending it back during the winter time (3 month of snow where I live).

For my PP software, I'm using Bibble Pro, what is setting that would eliminate the hot pixel?

Thanks!

marlon · 10-02-2008, 07:36 AM

The hot pixel issue on the 2second timer is indeed fixed in the latest firmware.
But hot pixels are fairly normal on camera, and you only ever see them if you pixel peep (which should be a crime anyway)

RiceHigh · 10-02-2008, 07:41 AM

Originally Posted by marlon

The hot pixel issue on the 2second timer is indeed fixed in the latest firmware.
But hot pixels are fairly normal on camera, and you only ever see them if you pixel peep (which should be a crime anyway)

I have never seen hot pixels neither with my K100D (for non-long time exposure shootings) nor my 5D (for any shooting), although I have been consistently the crime you said :-)

cpopham · 10-02-2008, 11:59 AM

Originally Posted by RiceHigh

Hot pixels exist in every digital camera but the K20D has been regarded as the "DSLRs with most visible hot pixels *ever seen* by the DPR.

That's great, RH... because comments about the K20 are really relevant to the OP's K100 super. Check the EXIF on the attached image. Oh wait, you had no time for that because you just wanted to troll. Fantastic.

Originally Posted by RiceHigh

I would not recommend anyone to get the K20D.

What a surprise.

I was kind of hoping when I saw you'd posted in this thread that you might have actually respond helpfully to the OP's question, and was genuinely interested if you had, because it might have helped me also.

But no.

Originally Posted by laissezfaire

did more research, it's in every type of camera.

Yes, and you'll notice while RH was on his K20 rant he didn't say anything negative about the K100. I'll admit the hot pixels in mine (K100) did unnerve me at first, but mine don't appear all the time, and aren't really that easy to see when they do.

I stopped worrying about it. On the other hand, if yours is under warranty, you could always send it in to have them mapped out.

*laissezfaire* · 10-02-2008, 07:14 PM

Originally Posted by Canada_Rockies

I just did a quick Google search "Pentax k20d hot pixels" , and found that the hot pixel mapping is in the latest firmware update. Download and install and you can map them out.

I have a k100ds. I'm not worried about it anymore... I looked at a bunch of "good" shots I've taken and can't see them, so I just happened to stumble on the conditions that generate them, high ISO, 100%+ crop and low light with a very dark background.

rfortson · 10-02-2008, 08:22 PM

If you shoot raw, Photoshop Elements and many other programs automagically remove hot pixels when you process the image. I believe even the latest version of the Pentax software does this as well.

As you found out, all cameras have hot pixels. Despite Ricehigh's assertations, the K20D is no worse than any other. There was an issue in a few K20Ds where hot pixels showed up when using the built-in timer. I tried the "recipe" posted by others to see if my K20D showed the hot pixel problem and I never could repeat it, so it's certainly not as wide spread as RH implies. Also, Pentax posted a firmware fix that took care of the K20Ds that did have the problem.