Interesting Nikon D750 image problem

chuckles

chuckles

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Interesting conundrum - a friend sent me this photo taken on a D750 with 24-120mm lens (I know, bit like my friend has this rash/doctor scenario). I've tried to crop in and insert the selection. The other 'dirt' is rubbish thrown up from Rotor downwash.

I don't know whether it's straight out of the camera but I think it is - I'm waiting to hear back from him. When you zoom in on it you can see loads of black crosses/plus signs - looks like an Aliens Invaders screen :)

Can't think what is causing it - never seen anything like it before except in some sort of Pixel Mapping programme. Any ideas anybody?

crosses_insert.jpg
 
What brand memory card is it? Whatever brand it is, recover as many images you can from it and if you cant claim for a replacement under warranty chuck in in the bin (after physically breaking it).
When memory card start becoming unreliable they cannot be repaired. They will just cause you grief if you choose to continue using it.
 
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redsnappa said:
What brand memory card is it? Whatever brand it is, recover as many images you can from it and if you cant claim for a replacement under warranty chuck in in the bin (after physically breaking it).
When memory card start becoming unreliable they cannot be repaired. They will just cause you grief if you choose to continue using it.
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That's an idea - never thought about the memory card. I'll tell him.
 
Looks like sharpening artefacts to me, small black spots under a pixel in size, but blurred a bit bigger, being over sharpened.
 
chris malcolm said:
Looks like sharpening artefacts to me, small black spots under a pixel in size, but blurred a bit bigger, being over sharpened.
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I eventually got some originals from my friend. Even the RAW NEF, straight from the camera, shows this.... so, not a post-processing problem. I think the sensor needs re-mapping but I would insist that he gets the camera replaced.
 
chris malcolm said:
Looks like sharpening artefacts to me, small black spots under a pixel in size, but blurred a bit bigger, being over sharpened.
Click to expand...
When you zoom in you can see white squares with black crosses in the middle, not artefacts IMO. Wouldn't have thought they were dead pixels either though as would just expect blank/white pixels, but then I don't think I've seen dead sensor pixels before.
 
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chuckles said:
"my artefacts" ????

They exist in the RAW file so there shouldn't be any artefacts.
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Lol, fat fingers and auto correct. Should have said not artefacts ;)
 
Also try a 20 sec bulb raw shot with body cap on, after that do 2 sensor cleans in a row via camera settings. Turn off. Take a shot of the sky and check if they are in the same part of the frame.
 
twist said:
Has he tried any other raw software?
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Not certain... I got the files from him and I've tried in Irfanview, FastStone, ViewNXi and Photoshop - all the same. I've even copied them to a memory card and viewed in Cameras as well - still show.

twist said:
Also try a 20 sec bulb raw shot with body cap on, after that do 2 sensor cleans in a row via camera settings. Turn off. Take a shot of the sky and check if they are in the same part of the frame.
Click to expand...

Now that's a good idea - kind of forcing a pixel re-map. like it.
 
chris malcolm said:
Do they happen in all photographs? In the same places?
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I think so - I've asked him to check (and hot to do it in ViewNXi). Unfortunately, he only sent me the one image but two files - a NEF and JPG. (I do have another one from him but I'm not certain it's the whole frame or a crop)

[Edit] An update to this.

It seems the other shot I have is the full frame - I've checked the mapping data and (luckily) the area I chose has lower light level/different colour. It seems that there are no '+' indicators. I assume this means this pixel(s) are incapable of recording high light values.

Re-map or return for replacement I would say.
 
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I would return for replacement.
 
Nod said:
I would return for replacement.
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I think that's what's going to happen. He had 14 days to return for a replacement - today (day 13) they've made arrangements for a return.

I did speak to Nikon this morning (I was inquiring over something else) and I did ask about this. There is no way the 'user' can remap the pixels but they did suggest it was 'dead/stuck' pixel scenario. Interestingly the guy didn't poo-poo the idea ( @twist ) above with a long, dark exposure to reset the pixels.
 
chuckles said:
I think that's what's going to happen. He had 14 days to return for a replacement - today (day 13) they've made arrangements for a return.

I did speak to Nikon this morning (I was inquiring over something else) and I did ask about this. There is no way the 'user' can remap the pixels but they did suggest it was 'dead/stuck' pixel scenario. Interestingly the guy didn't poo-poo the idea ( @twist ) above with a long, dark exposure to reset the pixels.
Click to expand...

From what I read its the 'official' way to remap a Nikon, Sony does it automatically once a month from what I understand so you can do the date trick. Returns easy so best to go with that, hope it all works out for him.
 
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