Help! 7100 Magenta in images. Update-Simple Light Leaks

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I responded lower in the thread that the issue is light leaks. I will now use my cover on the viewfinder when doing time exposures (Nikon tells you to do this anyway). Thanks to all who gave suggestions.

Original post started here:
I recently took some long exposures with the new D7100. And most of my images turned out like this. I switched to lens to my D3100, and was able to get my shots, but what the heck is going on with the D7100?

The main purpose I purchased this camera was for long exposures, and now I find it not useable.

Sorry for the large photo, but that should have all the exposure info.

Setup D7100, 18-55, two Tiffen ND 1.2 (yes I tried some with just one ND, and it was still there)... On the D3100 the images are perfect.

(I removed the large image to make it easier to see the thread.)
 
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The Exif says you had White Balance set to "Flash". The image is overexposed a bit, too. And I don't understand the brown light under the rock on the right.
 
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The Exif says you had White Balance set to "Flash". The image is overexposed a bit, too. And I don't understand the brown light under the rock on the right.

I tried a bunch of different settings to try to make it go away. Some images have a bit less magenta, and some more.

As far as the brown light on the right. I think you are seeing what I am asking about.
 
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As it seems to be only a single band in the image my guess would be that the sensor is broken. I would send some images to a Nikon service center and ask their opinion.
 
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I agree with Kees that it may be worth sending a couple of images to Nikon for their opinion.

two Tiffen ND 1.2 (yes I tried some with just one ND, and it was still there)
I think that you should also see if you get the effect with no filters at similar exposure times.

At this time you cannot rule out a filter issue and you should be aware that a magenta cast can be a side effect of using ND filters as most are only 'neutral' across the visible spectrum of light. IR cut filters are availble which are said to solve the magenta problem

Normally you would expect to compensate for an overall cast either in post or camera WB - but this would be expected to be overall not banding. Your second image is a particularly good? example when lightened not only can you see a well defined magenta band but underneath what appears to be the reverse green, although cannot rule out flare or bloom actually on the water.

NDFilterBanding.jpg
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Thanks for the comments.

I'm going to try some testing with different lenses and different brand ND filters and see what happens before sending off to Nikon for comment. I want to make sure I'm not causing the issue.
 
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I will use this camera (ordered about 3 days ago) for long exposures also, and I asked Thom Hogan if it would be OK compared to a D600 = What should I chose.

I got a long scientific explanation, but the button line was, that there would certainly be a chance of more banding from the D7100, than the D600, but it depends about how long the exposure was.

Can this you get here be called banding ???

----

It is clear, that you get it whatever it is a bit overexposed or not, and as I understand, you get it also whatever WB you use ?

---

I do not know how to see the exif, can you tell how long the exposures was ?
 
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I have searched around since last post:

Try these things:

- Close the viewfinder, so no light can come in and try again
- Try also only shooting in live view, still close/hide for the light in the viewfinder
 
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Well, I thought of the light leak, too. I did testing last evening thinking it would be a leak, and of the three lenses, and two different mfg ND filters I had no banding on anything with the eye piece blocked or not. Now I am going to have to wait for the weekend, and get out mid day.

Steinar, without looking up the data, I like to expose as long as possible, so the images are probably in the 20 to 30 second range.

Tony, the images look similar to the ones in the link you provided.

It is interesting in about 40 years of photography I have never had a light leak issue with any camera until now which is what I think we will find. It is interesting that I didn't have that issue with the D40, or D3100.

Now, I know I am going to lose the little plastic cover...
 
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It is confirmed as light leaks. No problem with the sensor.

Body cap on, 25 second exposure, shine small flashlight into the eye piece, and the results are just the banding.

Cover the eye piece, and the image is black.

Here is just the banding. I guess there is a reason Nikon tells you to cover the viewfinder.

Thanks for your help. Now, I somehow need to not lose this little plastic cover...

DSC_3149_zpsb3144a1c.jpg~original
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Good news that it is not the sensor and a very effective demo of the effect. I know what you mean about losing the little plastic cover - anyway there is always duct tape to fall back on in an emergency (you just need to remember to carry it with you!) :biggrin:
 
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anyway there is always duct tape to fall back on in an emergency (you just need to remember to carry it with you!) :biggrin:

Get a roll of gaffer tape. It doesn't leave residue. Put a strip on your camera. So you don't have to remember. I attached a paperclip to my keyring, put a pencil cut down to 2" next to it and wrapped about 10" of gaffer tape around it. Now I always have a good length of it with me! (A trick learned from the strobist.com site)
 
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Gaffer tape that is what I should have said - no residue wonderful stuff :biggrin:
 
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Thanks Tony.

---

The last days I have searched A LOT after your thread here, and it looks like:

The sensors from D7100 and D5200 are more prone to banding than D7000 and D5100, and also more than D600 (my alternative to D7100).

Perhaps some will put it "much more prone" ?

The way to go:

- Shoot in 14-bit, and lossless compression (perhaps even use the 100 % lossless, not sure about the difference here, but at least use lossless compression)

- Cover the viewfinder

- If you get it anyhow, then use a program to get rid of it, it can be Topaz, NIK Dfine or RawTherapee – those have a non banding feature.
 
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Talked earlier today about the issue with my netdealer (he is a part time pro photographer), he was about to send the D7100 to me tomorrow, but he was willing to exchange it to a D600, and he tryed 2 copies, but both had the dust/oil-problem, so I stayed with the D7100, and I think I can manage the banding problem as mentioned above.

So Friday is the day - really looking forward.
 
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Joined
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Steinar, I think you will find this to be a very nice camera. If you take long exposures make sure to use the little cover on the viewfinder. I was glad when I found out it was simply a non-issue. It could be the better sensor that makes it more prone to stray light, but the solution is simple. Gaffers tape or the cover if you don't lose it.
 

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