SL2-S rolling shutter examples - could Leica warn about it?

[Photoworks]

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Sorry to hear you work was unusable, it is always a bad surprise. But you photos look unusual in the amount to artifacts I have not seen before.

I have shoot for opera house and film and TV sets many years. the lighting can be an issue and banding is always a lighting issue. All that camera related.

Like Rob I hat sets where I didn't notice on the camera not even zooming in. but back in editing it came up.

I found a blimp to work well, but I don't have one for Leica. In the past I use a cold weather cover on the camera, it is similar to rain covers with foam padding inside. I would try to find one of does if you have this issue again.

I often shoot on Sony A1 and flicker is almost fixed on this camera. Older Sony camera did display a flicker warning on the screen.

On many news sets this day the use giant screens in the background. I use the camera in mechanical shutter in this studios, the hosts have mic and the camera sound of the Leica is quite enough .
The problem is that banking on the screens can not be avoided in mechanical shutter at normal shutter speeds.

 

 

[Photoworks]

16 minutes ago, LocalHero1953 said:

The e-shutter can cause just as many problems outdoors as indoors - distortion of moving objects - and I am sure it is not intended mainly for outdoor use. The disadvantages of e-shutters have been recognised for many years and mitigated by photographers all that time. To be honest I was surprised that you (and I assume you are an experienced photographer) were not aware of it. But then I still get taken by surprise as well (e.g. I assumed the yellow colour of my early Barnack rangefinder was deterioration, when it is actually a 'feature') so you have my sympathy. Since it is such a simple thing to identify before taking lots of photos, I'm not surprised technological advance has focused on reducing the read-out time rather than adding new functionality ('Das Wesentliche' and all that).

Actually many sports photographers have the same issues in outdoor sports arena.

[FrozenInTime]

Sounds like there would be a market for a 50/1.7 Q3 variant ( with OIS or IBIS )

[Jean-Michel]

The SL2's sensor has 8368 lines of pixels across and 5584 lines of pixel up and down. I have no ideas of how the lines are read – across or down. Each line takes a really small amount of time to readout (1/30 second divided by either 8368 or 5584) before moving to the next. Quite incredible speed, but it still takes a whole 1/30 of a second to complete the exposure. Things, and light 'flicker' will have changed between the start and the end of the 1/30 second — you cannot fix that. Just like you cannot fix the elongation or shortening of a fast moving object caused by the moving slit of a focal plane shutter. The electronic shutter has some real advantages when one wants to photograph wide open in bright sunlight, but that's about it. A 'global' electronic shutter would be more like a leaf shutter and would be amazing; but how to you readout 47 or whatever megapixels instantaneously?!

[hansvons]

Sorry to hear that your images were damaged. Your pictures weren't damaged by your camera but by the lighting. To put things in perspective, in cinema land, the most expensive and poster child of all cine cameras, the Arri Alexa, would have the same problems. Thus, the light's frequency would be adjusted to the camera's needs to prevent that. It's the modern world's technology that not only covers with its LED technology everything in colours that are an ugly fad (magenta, anyone?) but also creates sync problems on many levels. Leica cannot fix that without a global shutter sensor. But if they used one, many would complain about slow frame rates, reduced sensitivity and other issues that come with that technology. Something has to give. And this time, it was your shoot. I know how much that would bother me. Deeply sorry.

Edited November 22, 2022 by hansvons

[geotrupede]

the problem is sadly common in contemporary lighting technology, as pulse width modulation is used almost all the time to dim output. basically the apparent reduction of light output is achieved by switching on and off the source very quickly. keeping the source more off than on achieves lower levels of output (less light) and vice versa. 

What this means is that when images are recorded the frame is read line by line and at each line a different status of the source could occur, on or off. and thus the dark bands followed by lit bands in the resulting image.

a cheap way to check the frequency of this on/off is to drag an exposure with a slow time, for example 1/15th, aiming at a light source. if you can see the light blinking along the trail then by counting the dots you can tell how many times was on/off within 1/15th of a second and so the frequency.

a note, this has nothing to do with the power supply, if it not the old school flicker that was seen in magnetic ballasts or incandescent lighting of small power. it is with LEDs. 

good news is that high end lighting systems should be able to address the issue by using hybrid version of the pulse width modulation, but not always.

so one always need to test few shots and see what happens before setting on a shutter speed/iso/f.

G.

 

 

[Photoworks]

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11 hours ago, Jean-Michel said:

The SL2's sensor has 8368 lines of pixels across and 5584 lines of pixel up and down. I have no ideas of how the lines are read – across or down. Each line takes a really small amount of time to readout (1/30 second divided by either 8368 or 5584) before moving to the next. Quite incredible speed, but it still takes a whole 1/30 of a second to complete the exposure. Things, and light 'flicker' will have changed between the start and the end of the 1/30 second — you cannot fix that. Just like you cannot fix the elongation or shortening of a fast moving object caused by the moving slit of a focal plane shutter. The electronic shutter has some real advantages when one wants to photograph wide open in bright sunlight, but that's about it. A 'global' electronic shutter would be more like a leaf shutter and would be amazing; but how to you readout 47 or whatever megapixels instantaneously?!

that is true with Leica SL2. evermore evident on M11.

But Sony has quicker readout , so it must be possible to avoid flicker .

Solution is the concert places should use better lights. well that would only fix one location  LOL. many cities are going LED for the street illumination.

[Bikie John]

20 hours ago, Jean-Michel said:

The SL2's sensor has 8368 lines of pixels across and 5584 lines of pixel up and down. I have no ideas of how the lines are read – across or down. Each line takes a really small amount of time to readout (1/30 second divided by either 8368 or 5584) before moving to the next. Quite incredible speed, but it still takes a whole 1/30 of a second to complete the exposure. Things, and light 'flicker' will have changed between the start and the end of the 1/30 second — you cannot fix that. Just like you cannot fix the elongation or shortening of a fast moving object caused by the moving slit of a focal plane shutter. The electronic shutter has some real advantages when one wants to photograph wide open in bright sunlight, but that's about it. A 'global' electronic shutter would be more like a leaf shutter and would be amazing; but how to you readout 47 or whatever megapixels instantaneously?!

As far as I understand "global electronic shutter" (and of course I could be completely wrong) you wouldn't need to read all the data simultaneously. The idea of global shutter is that there is an extra layer in front of the sensor which can be opaque or transparent depending on the charge applied. So in effect it works like a mechanical shutter:

1. Turn front layer opaque.

2. Flush all data from sensor.

3. Turn front layer transparent for the duration of the exposure, then turn it opaque again.

4. Read data from sensor at your leisure.

Since all the data on the sensor was exposed at the same time, this would avoid rolling shutter and similar effects.

It will be nice when it works, I think it is under development but feel we may be waiting a while.

John

[Almizilero]

An unfortunate combination of light frequency and readout speed. I don't know any camera that is completely immune to this, but the Sony A1 and A9-series come close. Their readout-speeds are very fast and I almost never have issues like this. Additionally, they warn of flicker and have the ability to go into a special mode where you can adjust the shutter speed in the tiniest increments to match the light flicker. I never got into the science of this because it was basically never necessary. This is one of the reasons I still keep my old A9 around. AF-speed and accuracy and flicker resistance for concerts. But I use the SL2-S whenever I can, the ISO performace and colours are just something else! But I do take a couple of test shots at every venue just in case. If I see this, out comes the A9!

Edited November 23, 2022 by Almizilero

[BernardC]

13 hours ago, geotrupede said:

a note, this has nothing to do with the power supply, if it not the old school flicker that was seen in magnetic ballasts or incandescent lighting of small power. it is with LEDs.

It has to do with the electronic design of the lights, and ultimately with saving a few cents. Flicker can be reduced massively with a cheap smoothing capacitor that maintains voltage across the LED. Using a higher frequency for pulse width modulation also helps. I'm surprised that the issue showed-up so dramatically in a professional venue, it's something that is more common with cheap LED fixtures, or very old CFL fixtures.

[MRJohn]

7 hours ago, Almizilero said:

An unfortunate combination of light frequency and readout speed. I don't know any camera that is completely immune to this, but the Sony A1 and A9-series come close. Their readout-speeds are very fast and I almost never have issues like this. Additionally, they warn of flicker and have the ability to go into a special mode where you can adjust the shutter speed in the tiniest increments to match the light flicker. I never got into the science of this because it was basically never necessary. This is one of the reasons I still keep my old A9 around. AF-speed and accuracy and flicker resistance for concerts. But I use the SL2-S whenever I can, the ISO performace and colours are just something else! But I do take a couple of test shots at every venue just in case. If I see this, out comes the A9!

thanks for this, happy to read that Sony does have a function to warn about flicker, so Leica might be able to do the same, if they wanted

[MRJohn]

6 hours ago, BernardC said:

It has to do with the electronic design of the lights, and ultimately with saving a few cents. Flicker can be reduced massively with a cheap smoothing capacitor that maintains voltage across the LED. Using a higher frequency for pulse width modulation also helps. I'm surprised that the issue showed-up so dramatically in a professional venue, it's something that is more common with cheap LED fixtures, or very old CFL fixtures.

it is interesting that at another venue I had zero issues with the same settings

[MRJohn]

Just wanted to say "thank you" to the constructive input in this thread, learned a lot. 

[Simone_DF]

1 hour ago, MRJohn said:

thanks for this, happy to read that Sony does have a function to warn about flicker, so Leica might be able to do the same, if they wanted

Yes, but they also need to know about it. Maybe you could write an email with your samples and your proposed solution to implement a warning and send it to Leica.

[SrMi]

Page 213 of SL2-S manual:

Problem: Horizontal stripes

Cause: Picture was taken with electronic shutter under a light source like a fluorescent lamp

Suggestion: Try shorter shutter speeds

[Jean-Michel]

3 hours ago, SrMi said:

Page 213 of SL2-S manual:

Problem: Horizontal stripes

Cause: Picture was taken with electronic shutter under a light source like a fluorescent lamp

Suggestion: Try shorter shutter speeds

“Try shorter shutter speeds” is confusing. Shutter speed never varies, that is the time it takes for a shutter to open or close. What varies is the exposure time. So do they mean a shorter exposure time or do they mean a lower denominator, eg.: 1/250 rather than 1/4000 ?

The incorrect une of “shutter speed “ to describe the exposure time is one of my pet peeves. That term should be banned!

[SrMi]

29 minutes ago, Jean-Michel said:

“Try shorter shutter speeds” is confusing. Shutter speed never varies, that is the time it takes for a shutter to open or close. What varies is the exposure time. So do they mean a shorter exposure time or do they mean a lower denominator, eg.: 1/250 rather than 1/4000 ?

The incorrect une of “shutter speed “ to describe the exposure time is one of my pet peeves. That term should be banned!

Good point. Unfortunately, the use of shutter speed is much more common than exposure time (e.g., shutter speed priority, shutter speed setting dial).

[Photoworks]

the shutter speed is not a valid argument  if you are shooting moving subject.

You can't shoot below 1/60 . well you can but the result maybe undesired .

this cheep lights once they are dinned they flicker and any shutter speed.

I did I shoot at the philharmonic , they had flicker everywhere .

[LocalHero1953]

It's not just dimmed lights - many lights that have insufficient buffering show flickering with mains frequency: fluorescent, LED. The high pressure sodium lights in my church also produce this effect - they are undimmable.

Traditional incandescent light bulbs don't show flickering because their illumination is produced by a hot element and gas that cannot cool down between AC cycles. 

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[SrMi]

16 hours ago, SrMi said:

Page 213 of SL2-S manual:

Problem: Horizontal stripes

Cause: Picture was taken with electronic shutter under a light source like a fluorescent lamp

Suggestion: Try shorter shutter speeds

The point of this post was to show that Leica does warn about horizontal stripes.