Smudge on DCS760c raws

[SQLGuy]

I was capturing some PDR shots for Bill Claff and noticed this "smudge" in the middle of raw dark frames and underexposed frames. This is what they look like in Google Drive (both the previews and if you open the images there). If I import one of the DCRs into Lightroom, I don't see the smudge initially, but it is there if I raise the exposure by 5 stops, and is barely visible at 3.5 stops of push.

https://drive.google.com/file/d/1kA6HuI ... share_link

Any ideas what I'm seeing here? Is this normal?

Also, any suggestions on how I can inline an image that's hosted on Google Drive?

Thanks,
Paul

[NikonWeb]

Could it simply be a fingerprint on the sensor? If you only see it when pushing 3.5 + stops I personally wouldn't worry about it.

Google drive images inline seems to be an issue. I'll see if I can find a solution. Best thing would be to upload photos directly to the forum (currently not possible), but that could cause some issues down the road (server space limitations).

Jarle

[pieroc91]

How strange, are those previews of completely dark images or theres an actual picture?

If that's an actual picture i check for something on the light path, a fingerprint on the sensor can be one of those problems.

Not sure how the dark current elimination works on the 760 but that can be a ghost of a previous calibration.

I'd make sure to factory reset and let it self calibrate as much as possible

[SQLGuy]

They are dark frames. That is part of the PDR evaluation process. In this case, body cap on, viewfinder shutter closed, 1/8000th at base ISO.

[pieroc91]

That discards completely a problem in the light path, i'd try to recalibrate the internals of the camera if possible, if not you can check where the problem is by disconnecting the CCD and seeing how it behaves... if you feel like going inside the camera.

[SQLGuy]

Recalibrating the camera and running with the CCD disconnected sound like tasks that require access to service documentation and tools that I don't have. Any idea where to get DCS service manuals?

[pieroc91]

I don't think that that kind of info is on the wild.

Not sure about the calibration, I skipped a few generations of DCS, the NC2000e doesn't have any calibration at all, it saves everything and then all the processing is done on the twain plugin. On the other hand the DCS Pro 14/N recalibrates itself at random, specially if you need it to work fast it senses that and spends 45 seconds "Recalibrating Camera".

If doing some factory reset from the menu doesn't recalibrate it then I don't think the user can do that.

As for removing the CCD isn't often a hard task, you should be careful while doing it and have previously worked with flex cables, on the NC2000 you just remove the back and disconnect the CCD flex, on the DCS100 you open the back and pull the sensor out. On the 14/n you can disconnect the whole CCD/preamp board after removing the back cover (the one with the display and buttons).

It is always advised to use ESD precautions, CCDs and part of the electronics can be damaged if you are very unlucky.

[SQLGuy]

The 760 doesn't have a "back" like the 4xx and earlier cameras. It's more like the 14 and SLR models in that it has a heavily integrated set of digital parts in a replacement lower case.

[pieroc91]

I assume the construction will b more in the line of the 14/n, those are much more integrated but not as much as Nikon or Canon body, they left quite some room on the inside to work.
On the 14/n there were no hidden screw or anything tricky, ot was a very easy to service device.
Here are some photos of my 14/n when I took it apart to fix the CF slot https://imgur.com/gallery/5Q4ofr

[pieroc91]

It is advisable that if you never worked inside a camera you start with another less important one, they all have a similar construction.

If you grab a model with integrated flash for practice be careful when disassembling because the capacitor can retain a good charge and give you a nasty shock (nowhere near lethal but something you'll remember many years later), this is not a problem on the Kodak since the F5 has no built in flash.

[NikonWeb]

Recalibrating the camera and running with the CCD disconnected sound like tasks that require access to service documentation and tools that I don't have. Any idea where to get DCS service manuals?

I've made a few requests regarding .cal files and repair manuals.

Jim McGarvey don't have any: "Regarding documents, I do not have repair manuals for any of the cameras ... I don't know what happened to the cal files. I never had copies myself. Midwest Camera must have had them when they were repairing. That's probably the last place they existed."

Midwest Camera Repair in Michigan is the Exclusive Authorized Service Center in North America for Kodak Professional Digital Products. Here's their reply:

Originally we only service the camera bodies for Kodak on the Pro models starting with the models that used the N90 bodies (400 series). If Kodak received a camera with a body issue Kodak would remove the body from the digital back and replace with a rebuilt body and then ship us the bodies in bulk to rebuild.

When they decided to close down their repair department that’s when we started repairing the complete units. They had us repair the 500, 600 and 700 series but they were already discontinued and parts for the digital back were scarce. We mostly repaired the 14n, SLR-n and SLR-c for them and Pro Backs.

We purchased out their part and test equipment, it included 4 computers loaded with all the calibration software that only went back to the 400 series, thought the years the computer hard drive started to fail one by one that we thrown out, we no longer have any of the computers and were never give hard copies (disk or CD’s) of the software.

So on the 400 series our manuals are only for the camera portion, 500, 600, 700, 14n, SLR-n and SLR-c we have complete manuals but they're paper.

BTW, Midwest Camera still have batteries for the Kodak 14n, SLR-n and SLR-c (April 2023). "New original OEM, never been charge so the chemicals are not activated."

http://www.midwestcamera.com/kpro.html

Jarle

[SQLGuy]

It is advisable that if you never worked inside a camera you start with another less important one, they all have a similar construction.

I would definitely disagree with that statement. Purpose built digital SLRs are fairly different from composites like the 760, which are different again from the 460. My Canon T90, where I had to remove the shutter to clean the release magnets, is dramatically different internally from a Canon 5D. Modern digital cameras are modular and have a lot of connectors for FPCBs, and they actually have proper circuit boards. Newer mirrorless cameras are even better/more serviceable in this respect. The T90 has a design that's more like a Maxxum 9000... where there are a lot of FPCBs soldered together or connected by individual soldered wires. This gets even worse in something like the EOS 3, where you have a plastic chassis with the shutter, mirror box, and motors, that's basically wrapped in four or five layers of FPCB that are soldered and jumpered together.

Going back further, cameras are much more like small clocks. A Leica IIIF has basically one wire to desolder, but a lot more pivots and sliding surfaces to be cleaned and properly oiled or greased.

If you grab a model with integrated flash for practice be careful when disassembling because the capacitor can retain a good charge and give you a nasty shock (nowhere near lethal but something you'll remember many years later), this is not a problem on the Kodak since the F5 has no built in flash.

[pieroc91]

It is advisable that if you never worked inside a camera you start with another less important one, they all have a similar construction.

I would definitely disagree with that statement. Purpose built digital SLRs are fairly different from composites like the 760, which are different again from the 460. My Canon T90, where I had to remove the shutter to clean the release magnets, is dramatically different internally from a Canon 5D. Modern digital cameras are modular and have a lot of connectors for FPCBs, and they actually have proper circuit boards. Newer mirrorless cameras are even better/more serviceable in this respect. The T90 has a design that's more like a Maxxum 9000... where there are a lot of FPCBs soldered together or connected by individual soldered wires. This gets even worse in something like the EOS 3, where you have a plastic chassis with the shutter, mirror box, and motors, that's basically wrapped in four or five layers of FPCB that are soldered and jumpered together.

Going back further, cameras are much more like small clocks. A Leica IIIF has basically one wire to desolder, but a lot more pivots and sliding surfaces to be cleaned and properly oiled or greased.

If you grab a model with integrated flash for practice be careful when disassembling because the capacitor can retain a good charge and give you a nasty shock (nowhere near lethal but something you'll remember many years later), this is not a problem on the Kodak since the F5 has no built in flash.

I'd should be more specific, yes, I was talking about mostly modern DSLRs but not the newest ones, something like they are quite similar a Rebel XT, the DCS14n, a Finepix S2 and a Nikon D70, I've serviced those specific models and using the same logic when taking them apart will get you to similar results.
Design-wise speaking I wouldn't consider the 400 series a camera but an add-on for a very specific film camera, in line as any digital back.
The models I listed before they all look integrated but internally they still are a film camera with a digital back bolted on, a very common failure on the D70 is the fuse of the digital part blowing up due to changing lens with the camera turned on and the digital parts of the display turns off and it behaves like a film camera, you get speed, diaphgram, flash and autofocus, but the ISO and image counter disappear.

Analog cameras from the 80s are a nightmare to work, old FPCBs are very brittle, working on the viewfinder of a Canon A1 is like dismantling a bomb, going older on something like a OM1 is also a nightmare of pulleys and pinions and small springs, like a Rube Goldberg machine.
And yeah, the older I worked on was a Roilleiflex T, that felt like those instagram videos of asians restoring high end mechanical watches.
You can really see how technology had changed a lot in these years by looking at the design, specially the higher end models with all the bells and whistles.