How to remove horizontal banding caused by LED lighting

[Mario_tr]

Hi, does anybody knows how to remove horizontal banding caused by LED lighting when we shooted using silent mode with mirrorless cameras ?

does you know a method using Photoshop to do this? Or a photoshop or lightroom plug-in that works for this problem?

this is an example of the problem:

Picture was taken with a Sony A6300 digital camera.

[Trevor.Dennis · Accepted solution]

I was not aware of this affect.  Do you know what causes it?  Is some sort of artefact that happens with Mirrorless cameras and LED lighting panels?

It's not going to be an easy fix.  I tried using curves, but it was tricking getting the layer mask to align with the darker areas.

The best I could come up with was slow and careful use of the Dodge and Burn tools.  Set the strength really low (10%) and use a fully soft brush set to Midtones, and about the size of the dark bands.  Then slow brush out the shadows.

I have pasted this in the same size you uploaded it

[D Fosse]

Trevor.Dennis  wrote

I was not aware of this effect.  Do you know what causes it? 

This has to be the mains 50Hz frequency interfering with a scanning sensor at a certain shutter speed. It's the same effect as waving your spread fingers under a fluorescent tube.

I'm considering a Sony alpha, precisely because the clanking shutter of my Nikons is just too much in some delicate situations. It's very useful to know in advance that this is a potential problem.

[c.pfaffenbichler]

Do you still have the RAW data?

[Mario_tr]

Yes I have.

[Mario_tr]

Led lighting dimming (on cheap ones) are done simply by pulsing light and not by the variation of intensity (technically it is call duty-cycle). Tank you for the answers.

[fulldecent2]

FYI, an expensive LED does dimming also by using a duty cycle.

This is the way to dim a diode.

[c.pfaffenbichler]

Yes I have.

Can we see it?

[Francesco Della Peruta]

You can try to start with this:

Learn How To Fix Color Banding Using Just One Simple Tool | Fstoppers

[c.pfaffenbichler]

The person in the foreground’s skin and the presumably wooden structure in the background seem to be affected differently for example, so unless the color data is still available I doubt a reasonably efficient solution may be available.

[Trevor.Dennis]

c.pfaffenbichler  wrote

The person in the foreground’s skin and the presumably wooden structure in the background seem to be affected differently for example, so unless the color data is still available I doubt a reasonably efficient solution may be available.

c.p. I thought that was probably down to distance, and multi-path (reflected) light averaging out the effect to some extent.

Dag, is all LED lighting DC, and thus is not going to pulse with mains frequency?  What I don't think we know yet (unless I missed it) is if the LED lighting in question is household down lighters, or photographic LED panels?   As far as I Know, both use DC.  I have a 15A PSU I obtained for homemade LED light panels, and while this is definitely going to switch mode, I'm guessing it has decent smoothing on its output.   This is the same thing that powers LED household down lighters.

I have admit ignorance about mirrorless camera shutters, and what sync speed issues they have.  Here again, I'm guessing, but do they have leaf shutters?  Does every lens have a shutter?  That would certainly allow faster sync speeds, but I imagine there would still be a limit?

What I am trying to pin down here, is what might have caused this banding?  The image appears to have been taken in lowish light, but lets say it used a 1/60th second.  There are seven bands running across the image.  How does that correlate with 50Hz mains?  I'm not getting it, and would really like to understand.

[Trevor.Dennis]

Question:  Is this a still from a video clip, or a straight still photograph?

[D Fosse]

Trevor.Dennis  wrote

Dag, is all LED lighting DC, and thus is not going to pulse with mains frequency?

Maybe it's not the mains frequency - but LEDs do tend to start flickering for any number of reasons. Try to put a dimmer on one, and you get flicker. Or too many hooked up to the same circuit. Sometimes it's barely perceptible to the eye, but I'm sure a camera sensor could pick it up under the right circumstances.

In any case, it's the only explanation that makes sense. I'm as ignorant as you when it comes to mirrorless shutters, but the photographs I've seen of the Sony alphas clearly show a naked sensor in there. So to determine shutter speed, there is probably a certain scanning speed.

[Trevor.Dennis]

I've had a bit of a hunt round, and it seems that LEDs with variable colour temperature are prone to flickr.  Something to do with pulsing the three different colours (RGB?).  Different length pulses for each colour to adjust the colour?  There's a lot of info about workarounds, but I thought it was for shooting video.  It is also to do with electronic shutters.

I'd need a nice easy YouTube demonstration to explain it .

[D Fosse]

Trevor.Dennis  wrote

I'd need a nice easy YouTube demonstration to explain it .

From what I can tell, there's a YouTube video explaining everything you didn't even know existed. And there's a YouTube video explaining why you didn't know it existed. There's probably even a YouTube video explaining YouTube, and how it came to absorb the entire universe.

So don't worry, there is one, rest assured

[c.pfaffenbichler]

c.p. I thought that was probably down to distance, and multi-path (reflected) light averaging out the effect to some extent.

Good point; but even for isolating the foreground components the full color content might be better.

[TheThunderKatz]

Hello, 

I experienced a similar issue to the one being discussed here and I'm interested in the solution you have in mind,  for files where raw data is available. I tried creating a copy of the layer,  inverting it and creating a mask, to finally brush the lines cause by the flickering in. But off course, the result is having gray lines, since I'm just averaging the two layers. 

I'd greatly appreciate any insights. 

[D Fosse]

This one of those tricky issues you can't really apply any automatic fixes to. Even if you fix one, a series from the same shoot will have the stripes in different positions, and if you have auto exposure they will also be different width with different shutter speeds.

The method demonstrated by Norman Sanders above looks attractive, but if you look closer it takes a lot of detail and quality with it.

The lesson I've drawn from it all, is to use the mechanical shutter if at all possible. If I have to shoot in silent mode with LED lighting, I always do some test shots to determine the shutter speed range to avoid. Adjust ISO to stay away from that range.

If I get this with an important image (thankfully rare), I do it manually. Curves layer, shift click the brush for each line. 

If anyone has a better way, I'm all ears.

[Lumigraphics]

Use a camera that has an anti-banding/flicker reduction mode.

https://support.usa.canon.com/kb/index?page=content&id=ART162900

https://helpguide.sony.net/ilc/1710/v1/en/contents/TP0001661945.html

https://nps.nikonimaging.com/technical_solutions/d500_tips/useful/flicker_reduction/

[D Fosse]

The Sony link is for the a7r III, which is the one I have. There's still pronounced LED banding, and the only certain way is to determine in advance the range of shutter speeds to avoid. This is caused by interference between sensor scanning and rate of LED blinking, so it is possible to avoid completely. But you need to test shutter speeds.

[Lumigraphics]

Yep its a royal PITA. My 5Dsr has this feature and it does work but it takes some fooling with. I'm not sure of the easiest way to fix this in software. I wonder if there is a filter in ImageJ?

[Francesco Della Peruta]

Another way... obviously your situation is different, but you have to find a way to isolate the banding with some filter or channel effect:

How To: Eliminate Banding From Your Scans | Film Advance

[Norman Sanders]

Two questions regarding the original photography under these lighting conditions: 

What is the effect of longer exposure?

Can this be resolved with camera burst and then, in PS, stacking aligned layers, smart object, then Layers > Smart Object > Stack Mode > Median?

[Lumigraphics]

https://www.sony.com/electronics/support/articles/00122281

[Christopher J Photos]

I found this article on the Sony website helpful as I was experience a similar issue when using high speed sync and fast shutter speed on some indoor food photography setups:

The Image Shows Yellow Horizontal Lines or Banding Effects | Sony USA