A peculiar type of banding on A7Rii

[z_b_h]

hello everyone,

 

i need help with a very peculiar banding problem i have observed with my A7Rii.

 

my lens is the e mount native sony zeiss 55mm f1.8.

 

when shooting indoors, there often is a dark band clouding part of the picture taken. if i take stream of pictures in continuous mode or single shots one after the other, this is very visible. band is moving up and down sometimes clearing the whole picture, sometimes blocking it all, sometimes wider, narrower, denser...

 

i suspected shutter frequency problems, like you would see when shooting a pc monitor but i think this is different.

 

please take a look at my pictures, i downsized them considerably for ease of download. one single picture does not tell much but looking at them in series will tell the whole story.

 

typically they were shot wide open and 1/250 but the results are not any different at f8 either. changing the iso does make a difference either.

 

i tried shooting with a sony rx10 and did not experience similar problems.

 

here are my links:

https://www.dropbox.com/sh/qkq2mlh46d1p3vr/AADU5mjRcQoZZ4NTZu6--Y0Sa?dl=0

https://www.dropbox.com/sh/kc1sfitf5836n1a/AAAHT0KMOuC5fnT3CVEy0MEHa?dl=0

https://www.dropbox.com/sh/uisyja5zp74ymuf/AAAsz-k-pJMIs1F74rC8Utwna?dl=0

 

attached the files on the first link directly:

 

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[Guest Peter Kelly]

It could be looked on as shutter frequency problems, but it's not a camera problem!

 

It's actually down to your lighting, which will flicker and vary to a degree, depending upon type.

Fluorescent and LED are notorious for it and the only way around is to slow your shutter, or use flash.

[lenoindex]

It could be looked on as shutter frequency problems, but it's not a camera problem!

 

It's actually down to your lighting, which will flicker and vary to a degree, depending upon type.

Fluorescent and LED are notorious for it and the only way around is to slow your shutter, or use flash.

happens to me occasionally out door dark environment too. My theory is could be a bug/limitation with E front curtain shutter.     

[VTC]

"happens to me occasionally out door dark environment too. My theory is could be a bug/limitation with E front curtain shutter."

Lighting fickers outdoors as well. Experienced this last Christmas rolling video at night with decorations in the background appearing as flickering even though the light, to the eye, looked constant and stable. Take photo of a flat screen computer monitor and you'll get the same banding. Slowing shutter speed eliminates it.

 

http://www.bhphotovideo.com/explora/video/tips-and-solutions/flicker-free-lights-and-why-they-are-important-you

[Guest Peter Kelly]

happens to me occasionally out door dark environment too. My theory is could be a bug/limitation with E front curtain shutter.     

 

That could be down to street lighting. It wouldn't take much to be apparent in otherwise low light. Of course, if you're out in the wilderness away from any artificial lights then I'd like to see what the bands look like, out of curiosity and so I'm ready for it if I'm in those situations.

[Golem]

Household LEDs

[z_b_h]

thanks everyone with the feedback..

 

my immediate reaction was the same.. taking pictures of pc monitors would result in multiple bands on each photo but in my example some shots are perfectly clear, some are completely dark while others have one gray band.. unlike the typical pc monitor example i never had multiple bands. tried the same shots back to back with my sony rx10 and no such problem.

 

any comments?

 

i have contacted the local sony.. they have the camera, i still have not heard their final reaction/feedback.

 

i will try to repeat these pictures  with a friend's a7rii as well. the problem is, not many own this new and expensive camera.

[Guest Peter Kelly]

I don't believe that the RX10 has the same type of shutter as the A7 cameras, which would explain the lack of banding.

 

Also, the number of bands will depend upon the frequency of the bulb and the resulting resonance.

[z_b_h]

thanks peter.

 

would the lens make a difference? if i were to repeat the same shots under the same lighting with a friend's a7rii but with a different lens (say 35mm instead of 55mm) ?

[Guest Peter Kelly]

No, the lens won't make a difference as the band is caused by the light being off, briefly, as the slot of the shutter moves down. The light will be uniform across the whole sensor, regardless of focal length.

 

Just in case you're unaware of what's involved, it's owing to the nature of most camera shutters in that they don't just open fully and then close fully after the set time; that would need far too powerful a motion for faster shutter speeds.

Rather they have two 'curtains', or edges. The first one begins to drop down to reveal the sensor and then, depending upon the shutter speed, the second one follows to close it. If you have set 1/200 then the edge of the second curtain passes over the shutter exactly 1/200 of a second after the first curtain. Effectively, if you watch it in slow motion, it can be a slot that moves down. The faster the shutter speed the quicker the second curtain has to follow and the narrower the slot.

 

As in:

 

 

If your flickering lights happen to be off at any particular time then that area of sensor will be darker, hence the banding. You can even have banding effects at the top of the frame when the shutter speed should be slow enough, as the light can flicker off just before the second curtained has travelled completely. It's all very frustrating and only checking the lights and testing will solve it, I'm afraid.

[Guest all8]

RX10 has a leaf shutter, imagine opening and closing aperture, rather than sliding curtain.

[z_b_h]

thanks peter. thanks all for the comments and feedback. you guys are great.

 

i do not have the camera with me. i will first wait for sony's response.

 

once i have the camera back, i will try to repeat the test with two cameras.

[Golem]

thanks peter.

 

would the lens make a difference? if i were to repeat the same shots

under the same lighting with a friend's a7rii but with a different lens

(say 35mm instead of 55mm) ?

   

  

You don't even need a lens. It's the shutter scanning the sensor

with the LED's "dead moment" occuring somewhere during that

scan. You could just put frosted paper over the camera's flange

instead of a lens. You should have no banding below 1/25 sec. 

   

BTW a leaf shutter doesn't scan. So it's immune to banding. But

at certain shutter speeds [above 1/25 sec] leaf shutters can still

have a problem. The exposure time might include a major piece

of the LED's "dead moment", resulting in underexposure. IOW

even with a leaf shutter, you may shoot a burst and see varying

exposures, despite using manual exposure and white balance.

[z_b_h]

finally tested other cameras in the same environment, same lighting: a sony a7rii and a nikon 800e..

 

the results are similar. maybe less severe. i had to push high shutter speeds (1/1000 or faster) on both to get the similar effect. 

 

my camera had issues even at slower shutter speeds (definitely at 1/250) but that s ok i guess. i still have not heard from sony. will call them today.

 

thanks again for all the feedback. you guys are great.

[Golem]

finally tested other cameras in the same environment, same lighting:

a sony a7rii and a nikon 800e..

 

the results are similar. maybe less severe. i had to push high shutter

speeds (1/1000 or faster) on both to get the similar effect. 

 

my camera had issues even at slower shutter speeds (definitely at

1/250) but that s ok i guess. i still have not heard from sony. will call

them today.

 

thanks again for all the feedback. you guys are great.

  

Sony customer service is notoriously near useless.

Lotsa luck. The facts are clearly in this thread. You

can call it "feedback" and wait for word from Sony .... 

[storyteller]

Have you tried turning off the EFCS?

[Golem]

Have you tried turning off the EFCS?

  

Mechanical both curtains, electronic 1st curtain,

electronic both curtains [a7R-II] ... it won't make

much difference. All those modes are scanning

across the format. Scanning makes bars when

the illumination is varying during the scan. Even

a global shutter will have a problem [as does a

leaf shutter] ... but it won't be shaped as bars. It

will be inconsistent exposure frame to frame.

[z_b_h]

Sony response: There is nothing wrong with your A7Rii..

 

I did not fight over it. I m happy to have my camera back.

 

As I mentioned before, I tried 2 other cameras, observed similar issues with both, maybe less pronounced. My mistake that I sent it over to Sony service in panic.

 

Sony service was not responsive at all. They did not tell me what they did with it, what the problem was.. All I got back is my camera with additional screwdriver marks on it.

 

I m not going to go in detail but my cumulative experience (including few other past issues..) with Sony service and communication is that they are useless, terrible, worst ever...

 

Thanks again for all the feedback.

[Poor Bokey]

Just picking up on the this old-ish thread as I've experienced the same problem. I theater I've been shooting in uses LEDs lighting along with other sources. I've had a hard time emanating the flicker ... last time I think I used 1/60th shutter speed (client has the clip ... can't check it at the moment, and it's been a while since I shot it).

 

I just came across this video:https://www.youtube.com/watch?v=rjHft9lYYc4 It recommends using a shutter speed that's double the frame rate; so 24fps equals 1/40 or 1/50 (he says 1/40) shutter speed.

 

I have yet to try it but I'm hopeful that this is the solution.

[Poor Bokey]

I just experimented with this technique under my kitchen led lighting ... I wasn't able to completely get rid of the flickering, and following the video tip I posted didn't help either (1/14th sec with 24fps). I don't like this. 

[markfireblade]

1/50th sec would be nearer....