A different take on the D810 bright spot issue...

Started Sep 3, 2014 | Discussions thread
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chuxter Forum Pro • Posts: 21,713
A different take on the D810 bright spot issue...

While trying to get proof for my hunch about the failure of the "Hot Pixel Map" on the D810, I have been carefully trying to get more examples.

I took a dark frame last week. I saved it in TIFF format. There was an area where two clusters of bright spots were close together, so I cropped that area and started gathering data. I found something interesting: It looks like the algorithm that uses the "Hot Pixel Map" was storing dark data in the wrong places, thus not overwriting the bright spots! Go look at the thread:


Today, I'm trying to get more samples to analyze. The first thing I noticed is that even when I setup the camera exactly as before, I got a totally different set of bright spots! I tried it several times.

Then I wondered if there might be something related to the file format and or the RAW converter that was affecting where the bright spots appeared? SO, I took a RAW + JPG dark frame [actually I did it 3 times, but there was no difference between the 3 images]. The settings were:

  • 64 ISO
  • 30-seconds
  • No in-camera fiddling, like LENR, Hi-ISO NR, Active D-lighting, etc

The I converted the RAW file with LR 5.6 and NX-D. I then put the three JPEG images on separate layers in Elements 12, so that I could compare them. I did only one thing to bring out the bright spots; in Elements, I set Shadows = 1.

I was expecting small, subtle differences, this is what I got:

RAW Dark Frame rendered by LR 5.6

RAW Dark Frame rendered by NX-D

JPEG Dark Frame rendered in the D810

I think the JPEG from the camera is most likely correct [it's believable].

I'm confused!

 chuxter's gear list:chuxter's gear list
Nikon D810 Nikon D500 Tamron SP 90mm F2.8 Di VC USD 1:1 Macro (F004) Sigma 24-105mm F4 DG OS HSM Tamron SP 150-600mm F/5-6.3 Di VC USD +2 more
Nikon D810
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