Sony A9 has random banding issues at ISO 100?!

[Don Haines]

Don,

Yes, problem seems to be not brand restricted. Canon anti-flicker won't help though as we deal here with multiple light sources flickering at multiple frequencies, sadly.
here is a similar case:

https://www.dpreview.com/forums/thread/4133297

p.s. I suspect that application of CPL may help to isolate frequencies in theory?

I rather doubt that this is a problem that is restricted to the Sony A9, and I think that it is a problem that will get bigger.

One has to understand how LED lighting panels work..... At full power, the LEDs are constantly on. To dim them, they pulse them on and off. For example, at half brightness, the LED will be turned on half of the time, and turned off half of the time. When you do that with an incandescent bulb, it takes tens of milliseconds to turn on and up to 100 milliseconds more to turn off, resulting as if you pulse it at 60hz the dimming is not noticeable to the human eye or to a camera.

LEDs turn on and off in Nanoseconds, so if you pulsed them at 60 hz, it would be a very noticeable flicker. The solution is to pulse them at a faster rate, say 1Khz.... At 1Khz, the human eye will not detect the flickering and the light levels will appear to be stable, but if you have a camera with a reasonably fast shutter, it will.

The same thing happens with florescent lighting.... older lighting flickers, some of the newer lighting is at a higher frequency and the flicker is too fast for the eye to detect...... BUT A CAMERA STILL CAN!

This is why Canon has been putting the anti-flicker software into every camera released since the 7D2. They realize that this is a problem and have taken steps to prevent it. I would suspect that other manufacturers will start giving the option.....

A decent algorithm for detecting flicker would also figure out the frequency and adjust accordingly, but that only works in simple cases where one source is the bulk of the light. You are right about the multiple sources, with each one at a different frequency or offset, the problem gets worse. It can still be detected and predicted in software (think spectrum analyzer), but the odds of finding a period when all the sources are stable gets more and more unlikely as the setup gets more complex...

 

[SecureGSM]

they do! Hence getting similar issues but not to that extent. we are going to come accross this issue more as LED lighting becoming widely adopted. electronic shutter is obviously most affected.

https://www.dpreview.com/forums/thread/4133297

guys discussed how LED lighting affects catwalk shoot with 1DXII at shutter speed 1/300s- 1/400s ( over x-sync, obviously).

Oh, c'mon. It's not like sports shooters shoot using shutter speeds faster than 1/250 s, right?

 

[neuroanatomist]

they do! Hence getting similar issues but not to that extent. we are going to come accross this issue more as LED lighting becoming widely adopted. electronic shutter is obviously most affected.

https://www.dpreview.com/forums/thread/4133297

guys discussed how LED lighting affects catwalk shoot with 1DXII at shutter speed 1/300s- 1/400s ( over x-sync, obviously).

Oh, c'mon. It's not like sports shooters shoot using shutter speeds faster than 1/250 s, right?

Sorry, I wasn't clear. I've edited my post to give the relevant bit a little more emphasis. Hope that clarifies! If not, I can add formal <sarcasm> tags.

 

[SecureGSM]

oops. my bad. 8)

they do! Hence getting similar issues but not to that extent. we are going to come accross this issue more as LED lighting becoming widely adopted. electronic shutter is obviously most affected.

https://www.dpreview.com/forums/thread/4133297

guys discussed how LED lighting affects catwalk shoot with 1DXII at shutter speed 1/300s- 1/400s ( over x-sync, obviously).

Oh, c'mon. It's not like sports shooters shoot using shutter speeds faster than 1/250 s, right?

Sorry, I wasn't clear. I've edited my post to give the relevant bit a little more emphasis. Hope that clarifies! If not, I can add formal <sarcasm> tags.

 

[ahsanford]

So just curious, if this impacts mechanical shutters as well, what does a sideline sports 1DX2 or D5 user do today to combat this lighting phenomenon? Anti-flicker can manage consistently flickering lighting, but under this mad blend of different lighting, what do they do?

Do they slow the shutter down? Do they keep snapping away at high shutter speeds and simply accept a certain percentage of banded shots?

- A

 

[Don Haines]

So just curious, if this impacts mechanical shutters as well, what does a sideline sports 1DX2 or D5 user do today to combat this lighting phenomenon? Anti-flicker can manage consistently flickering lighting, but under this mad blend of different lighting, what do they do?

Do they slow the shutter down? Do they keep snapping away at high shutter speeds and simply accept a certain percentage of banded shots?

- A

This might be a problem with no solution at the camera.... a choice between blur and bands.... A problem that will have to be solved by the lighting manufacturers....

I wonder if this phenomena will entice high-end LED lighting systems to change from time based modulation to percentage based modulation in the hope of evening out the lighting, or if they will go to a higher modulation frequency.....

 

[IglooEater]

So just curious, if this impacts mechanical shutters as well, what does a sideline sports 1DX2 or D5 user do today to combat this lighting phenomenon? Anti-flicker can manage consistently flickering lighting, but under this mad blend of different lighting, what do they do?

Do they slow the shutter down? Do they keep snapping away at high shutter speeds and simply accept a certain percentage of banded shots?

- A

From the sounds of it, this does not impact mechanical shutter. I would expect it not to do so, but I can be wrong. I think the sensor is read as a whole, with the shutter physically controlling the exposure time.

 

[9VIII]

So just curious, if this impacts mechanical shutters as well, what does a sideline sports 1DX2 or D5 user do today to combat this lighting phenomenon? Anti-flicker can manage consistently flickering lighting, but under this mad blend of different lighting, what do they do?

Do they slow the shutter down? Do they keep snapping away at high shutter speeds and simply accept a certain percentage of banded shots?

- A

This might be a problem with no solution at the camera.... a choice between blur and bands.... A problem that will have to be solved by the lighting manufacturers....

I wonder if this phenomena will entice high-end LED lighting systems to change from time based modulation to percentage based modulation in the hope of evening out the lighting, or if they will go to a higher modulation frequency.....

I bought some cheap LED bulbs for 99 cents a piece last month, they're probably on sale because of the flickering. I could never use those bulbs indoors every day, and now I'm starting to worry that CFL bulbs will stop being manufactured and getting "pure" light sources might become difficult.