D7100 - I need help solving the "green shadows" in skin tones problem

Started Apr 3, 2013 | Discussions thread
rouchefoucald
rouchefoucald Regular Member • Posts: 101
Re: None here

Mako2011 wrote:

rouchefoucald wrote:

mosswings wrote:

jackalopemaui wrote:

mosswings wrote:

Brejla wrote:

Great! Thanks for the chrome color profiles, I'll try it soon. I noticed chrome's really bad colors a while ago too.

About the green tone... I got a green-tinted shadow in a very underexposed image in bright sunlight once. Don't know what caused it. But I have green shadows in long-exposure night photos taken in street light quite often, that's because the white balance is set to warm street light which doesn't affect dark shadows.

This is a very old thread...but D7100 shadows, when pulled up, shift slightly green. Sony sensored Nikons shift slightly blue, if at all. Note also that very long exposures may display some purplish "amp noise" related to sensor heating in its digital circuitry. A common problem with all highly integrated sensors.

Also confirm that the greenish shadows are not related to a very bright light source in the image. Some blooming or streaking in the long direction of the sensor has been observed with such huge DR situations. The streaking takes the form of a very weak green shift with the streak width correlating to the vertical extent of the very bright light source.

The shadows on my D7100 seem to shift green at 12 bit and magenta at 14 bit...

Shadow color shifting has been identified with the setting/reporting of the sensor's black level. Black level is determined by a strip of blacked-out sensors on one edge of the chip. From these sensor outputs an absolute black level is computed. How this is done can cause color shifting.

See this discussion on the computation of black points:

http://www.dpreview.com/forums/thread/3789550

And the effect it can have on shadow color shifts:

http://www.dpreview.com/forums/thread/3779243

That you have a green cast in 12 bit and and magenta in 14 bit suggests that the effective black level being used in either the sensor or in the RAW converter is slightly too high in the the former and slightly too low in the latter.

It should be noted that the D5300 and later Nikon DX cameras use a different black level method that minimizes color shifts as compared to the D7100/D5200.

I have this exact same problem working with the D7000.

I don't have that issue with my sample of the D7000. That suggests the issue might be, as mosswings points out, with the RAW converter. What is your primary convertor?

Glad to hear you haven't ran into this. There's hope I guess. I use Lightroom and usually the Standard Nikon camera profile.

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