Sudden high camera noise

[JohnM]

I've used a DMK21AUO4 camera since 2009 when I bought one new.
I've been using FireCapture for a couple years and AviStack2 for about the same.
I developed a work flow that always produced good results for me, till recently.
Lately I've been working with a 102mm mod, a 60mm mod and my old stand by 40mm mini mod; all with consistently poor results.
This morning I've been reviewing recent AVIs and then looking at some older ones.
There is one thing in common. A sudden high level of camera noise.
Anybody using any of the TIS cameras seen something like this?
Thoughts, ideas?
Looks like snow here all day, but maybe tomorrow a chance for some clear sky to work with.

[marktownley]

Hmmm, not sure, but I follow the thread with interest...

[JohnM]

Big time mystery. Almost as if gain is being applied which will add noise with a DMK.
My only suspect at the moment is FireCapture which hasn't been opening up right.
It announces its displeasure with a pop up telling me some dll is missing, by clicking that warning it seems to open up and work.
Then this morning I noticed I have 2 versions of it installed on my observatory computer. Some sort of file corruption?

Anyway, next good day I'll get an AVI, then uninstall both those versions and down load the latest one and then see if the AVI is cleaner.

[Merlin66]

Not a known or common problem....many of us have had DMK's for a few years without incident.
Let's just hope it's a software issue.
(Before contacting Imaging Source, I'd try the camera with their IC V2 aquisition software)

[JohnM]

I might, but after I've cleaned the old FireCapture installations on that computers drive.
I've always liked it much better than IC Capture supplied by TIS.

[brianb11213]

Did you upgrade the software at pretty much the same time as the noise increased? Did you find that the exposure suddenly become shorter at the same time?

The only thing that I can think of that would give a sudden big increase in noise is a big lift in the gain.

I would expect any deterioration in the sensor to be either very slow and progressive (more pixels sticking) or instantly catastrophic.

Unusually high operating temperature will make the sensor more noisy at the same setting of gain but I would expect the effect to be subtle rather than blatant.

[JohnM]

I haven't made changes to anything for a couple years.
I don't remember if that hard starting of FireCapture started about the time I was getting a lot of noise or not.
If things go back to normal after I get that cleaned up and a new version installed I'll know what the cause was, otherwise, it's back to head scratching.
We don't have high temp issues around here. Supposed to be wayyy below 0 degrees F tonight.

[JohnM]

Lots of digging into problems arising with FireCapture indicates situations where corrupted files have caused strange camera behavior.
I suppose as soon as I saw issues with the program starting I should have removed it and reinstalled, but I didn't.
It's -10°F out right now, but by the time the Sun gets high enough to get on it it might warm up some and it is clear.

I might just start out with some WL, that will bypass any possible problems I may have with my Ha rigs.
Then I'll see what I get.

[swisswalter]

Hi John

I hope for you that it is only a software issue

[JohnM]

I was able to get out for a while yesterday, my old bones just don't work in that sub zero stuff any more.
I got the observatory computer cleaned up and downloaded the latest version of FireCapture.
Hmm, this new one is much more complex and harder to figure out than any of the older ones were.
Even installing it was hardly what I can call straightforward.
But did think I finally had it done before frozen fingers forced me back to the house and a warm fire.

This morning, nada!, it was gone when I accessed the computer remotely. Everything!?!

After the temperature gets above zero and the Sun is shining I guess I'll install IC Capture off my disc and update it for a try.
I need to do all that out there at the computer, using my virtual desktop from in the house has too much delay to do it easily.

[swisswalter]

Hi John

here it is bloddy cold too. We are sitting inside and enjoy the fire too. No open sky for days predicted

[JohnM]

No changes or updates to IC Capture?

I got it installed and waiting for Sol to find it's way out of a tree it gets in this time of year.

Then I'll go for a capture and see what I get.

[JohnM]

Could this be the problem?
An unretouched dark from today.

[swisswalter]

Hi John


very strange, very strange. Exists that pattern at any gain and gamma?

[swisswalter]

Hi John

yes I did see one like that. On my Canon Rebell XT, all hot pixels

[JohnM]

I have a folder full of darks, none show so much as a single hot pixel.
I use one camera and things always stayed set up pretty much the same so my darks were simple, for the processing we do a dark is a dark pretty much.
I made a new one yesterday for the heck of it, when I saw all the noise when processing I took a look at the dark. Yikes. Then looked at a bunch of old ones.
Sensor must be going. This sort of thing is way over my head, but I'll have to contact TIS next week.

[brianb11213]

I have a folder full of darks, none show so much as a single hot pixel.
Depends so much on exposure, gain & gamma.

Here's one of mine - 1 sec exposure, max gain, normal gamma ...
... and the same file with contrast stretching.

DMK21AU618, IC software. Note the amp glow in the top right corner!

[JohnM]

Thanks Brian.
The 618 has a different chip than the AUO4, don't know if that makes any difference.
When I make a dark frame I shoot an AVI at the same settings as the regular capture with the objective covered and then let AviStack2 create a dark from it for subtraction.

As soon as it warms up a little I'm going out and make some AVIs with just the camera at different settings and let AS2 create darks and see what they look like.

Have to admit this is getting way over my head, but I've never seen any hot pixels show on any of the darks I've made over the past several years.

[swisswalter]

Hi John

don't bother. You'll get there.

[JohnM]

OK, I've succeeded in totally confusing myself.
I just did about a dozen AVIs at the exposure times and gamma settings I would usually use.
With IC Capture, no brightness or gain applied.
Regardless of exposure, the white specks appear at about 90 gamma.

Now, did I have any darks I was using with white specks?, I dunno
I never really checked them.
I had a set of darks for different Ha and WL set ups and different apertures and EFLs.
I'd just pick one that fit what I was using and go with it with no problem till recently.

[JohnM]

Now in contact with TIS in Bremen, maybe we can figure out this thing.

[swisswalter]

Hi John

good luck, I'm sure you and TIS find a solution to get rid of the stars in your dark ;-)

[JohnM]

Stefan Geissler took the job, most here probably know him as the main spokesman/trouble shooter for the DMK cameras.
After looking at the photo I sent him he decided the sensor was developing a lot of hot pixels.

Then he wanted to know what I used it for and when told for Solar imaging said the Sun had burned up the chip!
Oh please!!!

I've used the camera for over 4 years and if the sensor was identified as failed didn't expect them to replace it for free.
I asked if I could send it to the US service center to get repaired, but haven't heard back.
I think about that point in our email exchange it must have been about quitting time in Germany, so hopefully an answer tomorrow.

[swisswalter]

Hi John

yes I did see one like that. On my Canon Rebell XT, all hot pixels

Hi John

din't I thought of that.


Well, if it is really true, I would like to know at what point of sun light exposure a CCD chip is getting harmed.

[JohnM]

Unfiltered magnified sunlight striking a camera sensor could no doubt fry it.
My issue is after selling the AS series of cameras for years TIS needs someone to handle problems of astrophotographers.

Even so I love that little camera and am still thinking about another with a larger chip.

[marktownley]

Then he wanted to know what I used it for and when told for Solar imaging said the Sun had burned up the chip!
Oh please!!!

I hope they don't follow this line for the sake of an easy answer... :dry:

[JohnM]

I don't know Mark, maybe it's too much to assume that they know we would be using proper filters.
One thing I still don't understand is if hot pixels across the sensor are adding noise a dark frame won't subtract it.

[Merlin66]

Like John, I've been using the DMK21 for over seven years...with PST/SM60/102 PST Mod etc with no issues, no drama...

[JohnM]

I was informed this morning that I could send the camera to the US service center but that it would go to Germany for repair anyway. And the only person who can arrange it is on vacation till after Thanksgiving.
No idea of what the costs will be and probably won't know till this person in Charlotte is back at work.

I'm still furious a factory rep would tell me Solar use would fry the sensor without even having any idea how it's done. Oh well, I'll get over that.

[swisswalter]

Hi John

I keep fingers crossed that it will work out fine for you