# D800 crazy magenta noise???



## afoto (Sep 13, 2013)

Hey everyone, so i just bought the D800 and am experiencing something very strange...

On some images i'm getting a very strong magenta line on the right side, I've uploaded images so you can see.

Here are the settings for each image:

1: (colour cast!)
Iso 2200
605 seconds

2: (no colour cast)
iso 800
920 seconds

3: (crazy colour cast)
iso 6400
131 seconds

4: (no colour cast)
iso 6400
30 seconds


obviously the first thought is that the long exposure high ISO is causing the problem. though as you can see some of them have it and some of them don't even though they are all relatively high iso with long shutter speeds.

Any thoughts? I used to get a similar problem with my D700 sometimes, but could never link it to one variable.
I read briefly somewhere about thermal noise but couldn't find any further information..

note: the back opening to the view finder was closed for all images.

any help would be great!


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## Gavjenks (Sep 13, 2013)

That's not "noise." it is happening in really obvious streaks and bands. Looks more like flare or light leaks.

Not necessarily a faulty camera at hundreds of seconds exposures, though. Possibly just bad technique. 

1) Are you using a lens hood? Do, if you aren't.
2) Are you covering up the viewfinder (light can leak in through it and bounce around and hit your sensor for long exposures)? Do, if you aren't.


The reason it happens in some and not others could be as simple as the moon was in a different position, or whatever, and the angle was right for a flare or leak, but then it moved and wasn't a problem 20 minutes later.


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## afoto (Sep 13, 2013)

Gavjenks said:


> 1) Are you using a lens hood? Do, if you aren't.
> 2) Are you covering up the viewfinder (light can leak in through it and bounce around and hit your sensor for long exposures)? Do, if you aren't.
> 
> 
> The reason it happens in some and not others could be as simple as the moon was in a different position, or whatever, and the angle was right for a flare or leak, but then it moved and wasn't a problem 20 minutes later.



hi gavjenks, thanks for the thoughts.

- yes using a lens hood
- yes the view finder was closed
- no moon that night

the other thought i had is that i didn't cover the little clear opening on the lens that shows your focus (i have problems with it when i shoot during the day and usually cover it up)
however the first two shots i uploaded were taken one right after the other, nothing on the camera was changed other then the iso..


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## Gavjenks (Sep 13, 2013)

Huh.  You know, when I look really hard, it very much seems to me that the color cast is not only streaky and leaky looking, but has almost the exact same PATTERN of streakiness in the two shots on the left, even though they're pointing at completely different things. You can see a bit of a band of more magenta-y-ness in the upper right of the slight color cast one, just like below.

It's almost like there's some sort of little red light on your camera or intervalometer or something that is getting into the image somehow.



Try taking some photos with the lens cap on at similar shutter speeds and ISOs (and viewfinder closed off)? Should rule out whether it's from the environment or from inside your camera.


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## Gavjenks (Sep 13, 2013)

Also, I would make sure that the viewfinder blocking device is actually doing its job. Try taking a really powerful flashlight or halogen light or something, and shining it right at the viewfinder while it is "blocked" and taking a similar exposure with the lens cap on, see if it changes anything.


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## Derrel (Sep 13, 2013)

I think the issue you're seeing could be what's commonly referred to as "amp noise", which can be an issue with long exposures on many d-slr cameras. You're also at pretty high ISO values as well.

Do you have long exposure noise reduction turned to ON? I bet not.


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## afoto (Sep 13, 2013)

Derrel said:


> I think the issue you're seeing could be what's commonly referred to as "amp noise", which can be an issue with long exposures on many d-slr cameras. You're also at pretty high ISO values as well.
> 
> Do you have long exposure noise reduction turned to ON? I bet not.



Hey Derrel, 

thanks for the thoughts! just did a bit of research and it seems like amp noise is probably the issue...

however! The first image, i did have noise reduction turned ON while the second image (no magenta) had the noise reduction turned OFF, which is what made me super confused.


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## Derrel (Sep 13, 2013)

Are noise reduction and long exposure noise reduction separate options?


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## afoto (Sep 13, 2013)

Derrel said:


> Are noise reduction and long exposure noise reduction separate options?



yes they are, in this instance i had the long exposure noise reduction on, would the other option work better?


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## Derrel (Sep 13, 2013)

afoto said:


> Derrel said:
> 
> 
> > Are noise reduction and long exposure noise reduction separate options?
> ...



I'm not sure, since I don't own a D800...but some tests might be in order, to see at what length of time the electronics give off enough "heat" to cause amp noise, at the ambient temperatures you were at. Amp noise on lengthy exposures is a pretty common issue with d-slrs. Looking at your four test shots, it "seems" that at ISO 800m things are pretty good, but that at ISO 2,200 and at ISO 6,400, there are some real issues. The longest exposure of 920 seconds was fine, and that was at ISO 800; shot #4 was ISO 6,400 at 30 seconds, and is fine, but ISO 6,400 at 121 seconds, so--there's likely a cutoff time at ISO 6,400 somewhere north of 30 seconds, but south of 121 seconds, where the images will be acceptable.

Since elevated ISOs are increased gain, it's a possibility that the bigger factor is ISO level,and not length of exposure, but obviously, as one can see by shots 3 and 4, there is at least SOME interrelationship between ISO level and exposure time.


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## amolitor (Sep 13, 2013)

It's also possible that you're seeing some sort of lens flare or out of focus element.

Are you sure nobody's walking around with a lit cigarette or a flashlight while these are going on? You're not checking the front element to see if you got the lens cap off, with a headlamp on?

These are all rather silly scenarios, I realize, but we all sometimes do silly stuff without really knowing it.


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## Gavjenks (Sep 13, 2013)

Looks consistent across situations. Doesn't rule out the possibility of the headlamp thing or something like that, consistently looking in from the same direction. Or an intervalometer-y thing hanging somewhere with a red light, etc.

But more likely due to something truly fixed with relation to the camera. Either the sensor itself, or an imperfect seal on the viewfinder seem most likely to me. Again, I think shooting images with the lens cap on and the same settings, with and without bright lights aimed at the viewfinder, would diagnose it pretty quickly.  No color at all? Probably flare or something in front of the lens. Color, and gets worse witha  halogen bulb at the viewfinder? Bad light seal at the viewfinder. Color, doesn't change with halogen bulb? Sensor amp noise.  If that is amp noise though, it's some of the worst I have ever seen by a factor of 5 or so. Returning for an exchange might not be out of the question, there. The other things are cheap fixes.


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## afoto (Sep 13, 2013)

thanks for all the input guys.

for now i think i'll do some experimenting with different variables, i'll keep the post updated if i find a common link.


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## clarnibass (Sep 14, 2013)

What lens did you use for these photos?


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## afoto (Sep 14, 2013)

clarnibass said:


> What lens did you use for these photos?



nikon 16-35mm


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## shefjr (Sep 15, 2013)

I took out my D800 last night in an attempt to see if my D800 would produce similar problems to yours. I did about 20 2 minutes exposures with an ISO of 1000 at f11. I was/am trying to do star trails using stack a matic in CS6(not going well). In either case, I wanted to let you know that I had no magenta noise or any other type of noise issues.


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## afoto (Sep 15, 2013)

thanks for the heads up shefjr.

also I've used StarStax for some of my star trail work, you should give it a try!


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## Bulb (Sep 15, 2013)

The first thing I would try to do is isolate the problem. Take a few shots of each one to make sure the problem still persists:


Try the lens on another camera (If that fails, the lens is the problem)
Try another lens on the camera (If that fails, the camera is the problem)
Just to be sure, take a shot with no lens attached. If there's still a problem then you can be sure that it's the camera.
If you find the camera to be the problem:


Try these shots at base (200) ISO
Try to take normal (not long-) exposures
Try without noise reduction (Then try it with)
Try without high ISO noise reduction (Then try it with)
If you are still having problems then I would suspect there to be a problem with the image sensor.


Lock up your mirror and get a good look at your sensor. Is there any sort of film or defect on it?
Do a comparison of different ISO settings to see if there's a point at which the noise will appear.
The next thing I would do is ship it in for warranty. No camera should be doing this if there isn't an external factor affecting it.


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## sleist (Sep 15, 2013)

Wasn't there a problem with some of the 16-35 f/4 during long exposures?  Is the lens new as well or just the camera?

Here's some discussion at LL:

Nikon 16-35mm f/4 long exposure problem

and a thread at DPReview:

d800 long exposure red band: Nikon FX SLR (D1-D4, D600-D800) Talk Forum: Digital Photography Review

I think Thom Hogan mentioned its as well.  Your shots seem pretty extreme, but if it's the same issue it's the lens that may be at fault.

For what it's worth.


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## Aloicious (Sep 16, 2013)

definitely looks like some kind of light leak to me too. from the links sleist posted it definitely looks similar, I'm wondering if there is some kind of light leak from the lens, I've done up to 25 min (1500s) single exposures on a D800 with a 14-24 at ISO3200 without that kind of noise showing up (although there is some amplifier noise on my images, as would be expected in such extremely long single exposures, I still don't see what you're seeing)...

I know you're already getting bombarded with suggestions on what to do to track down the issue, but personally I'd look at the lens first...I'd take a long exposure shot in a completely dark room, with the lens cap on and VF cover closed (where no light SHOULD be getting in), and use a flashlight going around the lens and VF and body and see if it is picking up any light leak on your exposures. try it with different lenses if it does show up, kindof light bulb mentioned, to narrow down a camera or lens problem...

I'd be interested in what you find with it.


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