D7100 'streaking'

Started Apr 7, 2013 | Discussions
Jussi Mattila New Member • Posts: 13
D7100 'streaking'
2

First of all, I'm a very happy owner of a new D7100, it's a huge upgrade from a D90! I love how it forces me to become a better photographer (and perhaps buy more expensive glass :-)) since the resolution is unbelievable, exposing camera shake and my poor focusing skills.

Anyway, I had a feeling that exposure with D7100 was not quite what I was used to. So, today I shot some quick practice shots around the house to get a feeling of it. While there was no noticeable difference in exposure between my trusty D90 and the D7100, going into Adobe Lightroom 4.4 I noticed that one D7100 picture had minor streaking visible in the shadows. I pushed exposure by +2 and saw this:

D7100, blinds 'streaking' to the shadowed area

EDIT: Full size picture (above) not visible in the post, here's a smaller version:

I put the lens and the same settings to the D90 (1/200, f2.8, ISO200, White balance was Auto so the colors were off, lens used Nikkor 50mm 1.8G) and took another shot. After +2 exposure in Lightroom, this is what I got:

D90 - no 'streaking'

Actually, there probably is some streaking in the D90 shot as well, but it is almost impossible to see unless really looking for it. With the D7100, the streaks disappear when the right hand side gets more exposed (changing to ISO400 still slightly visible, at ISO800 not anymore).

Both images uploaded here were imported to Lightroom as DNG, WB set at 5500, exposure +2, and exported as full-size JPG at 85% quality. I can provide raw files if anyone needs those.

My questions regarding the streaking with D7100 are:

1) Is this normal/expected?

2) Is there something that can be done to this in post-processing, if (STRONG if) encountered in real photos?

3) If this is normal and can't be fixed in PP, in what situations I need to be careful with the shadow exposure? Please remember that the issue was visible even before pushing exposure.

If you need additional information about the conditions, settings, etc. please ask, I'm sure I forgot something important!

To end on a high note, here's a D7100 photo of the only willing model in our house, taken at ISO3200 in natural light.

Our cat, Armas, strikes a pose

Nikon D7100 Nikon D90
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krikman Regular Member • Posts: 418
Re: D7100 'streaking'

Isuppose that visible streaks produced by lens, not by sensor. Try with another lens. But it is only assumption.

OP Jussi Mattila New Member • Posts: 13
Re: D7100 'streaking'

Thanks for the suggestion, I didn't consider the lens at all since D90 didn't show the issue. I'll take more shots with another lens tomorrow, since it's already dark outside (here in Finland).

mosswings Veteran Member • Posts: 8,702
Re: D7100 'streaking'

I'd like to know more of the EXIF data.  Was A-DL on?  What lens was being used?

This result is quite strange but quite faint.  That it is barely visible at +2 in the D90 and disappears completely as you increase ISO in the D7100 suggests that the effect is occurring right at the lower limits of the D7100's dynamic range at ISO 200 - and since the D90 has less DR, as well as less resolution, you don't see it at that ISO. It almost drowns in the noise floor - the exposure (a tricky one  for autoexposure, by the way) is biased towards the bright window in both cases.

The fact that the "streaking" appears to be a simple linear translation or reflection of the extremely bright window and blinds suggests possible ghosting in the lens that you're using.  It appears to be a faster lens (f2.8), and such lenses tend to be more susceptible to such off-axis problems.  That it also appears in the D90 shot supports this hypothesis.  The sensor surface is reflective as well and can set up strange light paths inside the lens when presented with such scenes.  It would have been interesting to do a shot at a higher aperture.  With a higher aperture the lens elements are blocked from seeing any errant reflections that the wide aperture permits.

A simpler test might be to set up a specular light source against a dark background in roughly the same geometry to see if you get a ghost image on the other side.

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Olympus Stylus 1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR +5 more
BlueBomberTurbo Senior Member • Posts: 1,389
Re: D7100 'streaking'

Yup, the D5200/D7100 will band if you push shadows too far, though it's not consistent fom one scene to another.  If you use mid/high ISO, the effect can go away, sometimes completely.

 BlueBomberTurbo's gear list:BlueBomberTurbo's gear list
Canon EF 100mm f/2.0 USM Sigma 70-200mm F2.8 EX DG Macro HSM II Sigma 8-16mm F4.5-5.6 DC HSM Sigma 17-50mm F2.8 EX DC OS HSM Sony Carl Zeiss Sonnar T* E 24mm F1.8 ZA +12 more
Jack Hogan Veteran Member • Posts: 6,507
Re: D7100 'streaking'

Jussi Mattila wrote:

If you need additional information about the conditions, settings, etc. please ask, I'm sure I forgot something important!

Hi Jussi,

Could you make the NEFs available so that we could take a closer look?

Jack

mosswings Veteran Member • Posts: 8,702
Re: D7100 'streaking'

BlueBomberTurbo wrote:

Yup, the D5200/D7100 will band if you push shadows too far, though it's not consistent fom one scene to another.  If you use mid/high ISO, the effect can go away, sometimes completely.

BlueBomberTurbo, this is very likely NOT deep shadow pattern noise ("banding").  That has completely different characteristics that what are presented in this image.  The width and spacing of deep shadow pattern noise bands is much narrower and is not related to any subject geometry.  The streaking in this image is clearly subject geometry related.

In the CCD age you could expect row or column overflow from extremely bright light sources, but the effect was gross and obvious. And it's not possible in CMOS based sensors.

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Olympus Stylus 1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR +5 more
OP Jussi Mattila New Member • Posts: 13
Re: D7100 'streaking'

ADL was off when using the D7100. I forgot to explicitly set that on the D90 where it was left on Auto. Good catch!

Lens was a Nikon 50mm 1.8G.

Thanks for the suggestion to do shots using different settings, I'll definitely shoot the same scene (or setup a light) tomorrow to get additional information on this issue.

To put this into perspective, I have already shot ~300 photos with the D7100 and the issue just doesn't exist in normal conditions. Still, it would be nice to know if this is something I should consider when composing a scene.

Horshack Veteran Member • Posts: 6,168
Reproduced on my D7100 (with NEF download link)
2

Using a Tamron 17-50mm BIM lens, shadows pushed +4EV to show it better. This is not the typical D5200/D7100 banding since the streaks are aligned/spaced to the light source from the blinds. Looks like sensor blooming to me, bleeding into the pixel row.

NEF Link (good for 5 days)

OP Jussi Mattila New Member • Posts: 13
Re: D7100 'streaking'

You are absolutely right, mosswings, the issue I describe is not deep shadow banding which, from the same camera (exposure +5), looks like this:

Exposure +5, banding visible

Clearly different from the 'streaks' in the original post.

OP Jussi Mattila New Member • Posts: 13
Re: D7100 'streaking' - NEF download link

Since they were requested here's a link to five shots I took of the scene while testing exposure. They are at ISO 100-1600.

D7100 streaking NEFs

OP Jussi Mattila New Member • Posts: 13
Re: D7100 'streaking'

I put the images available at: D7100 streaking NEFs

mosswings Veteran Member • Posts: 8,702
Re: Reproduced on my D7100 (with NEF download link)

Horshack wrote:

Using a Tamron 17-50mm BIM lens, shadows pushed +4EV to show it better. This is not the typical D5200/D7100 banding since the streaks are aligned/spaced to the light source from the blinds. Looks like sensor blooming to me, bleeding into the pixel row.

NEF Link (good for 5 days)

Horshack, fascinating.  I was of the impression that blooming was essentially banished when we moved away from CCD's bucket-brigade architecture to active-pixel architecture.

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Olympus Stylus 1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR +5 more
BlueBomberTurbo Senior Member • Posts: 1,389
Re: Reproduced on my D7100 (with NEF download link)

Horshack wrote:

Using a Tamron 17-50mm BIM lens, shadows pushed +4EV to show it better. This is not the typical D5200/D7100 banding since the streaks are aligned/spaced to the light source from the blinds. Looks like sensor blooming to me, bleeding into the pixel row.

NEF Link (good for 5 days)

Were there any lights on in the room, or is it purely from outside?

 BlueBomberTurbo's gear list:BlueBomberTurbo's gear list
Canon EF 100mm f/2.0 USM Sigma 70-200mm F2.8 EX DG Macro HSM II Sigma 8-16mm F4.5-5.6 DC HSM Sigma 17-50mm F2.8 EX DC OS HSM Sony Carl Zeiss Sonnar T* E 24mm F1.8 ZA +12 more
Horshack Veteran Member • Posts: 6,168
Here's a D5100 image for comparison

I can see a faint hint of it on the D5100 as well; it's more pronounced when the image is downsampled.

Horshack Veteran Member • Posts: 6,168
And D800 image for comparison

BlueBomberTurbo Senior Member • Posts: 1,389
Re: And D800 image for comparison

Something else to think about: this may be a form of lens flare, considering the intensity of the light source.  Try shooting the same shot again, but at an angle.

 BlueBomberTurbo's gear list:BlueBomberTurbo's gear list
Canon EF 100mm f/2.0 USM Sigma 70-200mm F2.8 EX DG Macro HSM II Sigma 8-16mm F4.5-5.6 DC HSM Sigma 17-50mm F2.8 EX DC OS HSM Sony Carl Zeiss Sonnar T* E 24mm F1.8 ZA +12 more
mosswings Veteran Member • Posts: 8,702
Re: Here's a D5100 image for comparison

Again fascinating.  Considering that increasing ISO beyond "native" ISO basically underfills the sensel well and gains it up at conversion, the well's highlight headroom increases, reducing any overflow tendencies.  The sensor DR still decreases, but now we open up the question of the full-well-capacity of the various sensor technologies.

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Olympus Stylus 1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR +5 more
mosswings Veteran Member • Posts: 8,702
Re: And D800 image for comparison

BlueBomberTurbo wrote:

Something else to think about: this may be a form of flare, considering the intensity of the light source.  Try shooting the same shot again, but at an angle.

That's what I meant by "ghosting".

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Olympus Stylus 1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR +5 more
Horshack Veteran Member • Posts: 6,168
And Canon 6D for comparison

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