Flickering images at DVinfo.net

Edsard Keuning · January 22nd, 2012, 06:02 AM

Hi,

I own the xf300 since a couple of days now. And when i'm filming there is flickering "banding" visible. (See sample)

I tried playing with the hertz setting. Arround 50 since i'm living in a PAL area, but also 60 and some lower values. However it doesnt seem to help. I also tried filming with different CP files, flicker reduction turned on and off but nothing removes these bandings.

I hope you guys have some tips.

Check the file overhere. Its raw straight from the camera
hotfile.com/dl/142955493/f89c4e6/AA020601.MXF.html

Chris Dickinson · January 27th, 2012, 09:31 AM

Hi - can you post something on Vimeo as that would be easier to view rather than expecting us to download stuff.

Cheers,

Chris

Edsard Keuning · February 3rd, 2012, 04:26 PM

I uploaded it to a download site because vimeo compresses the material. This way i can show the raw footage

Edsard Keuning · February 3rd, 2012, 04:31 PM

Here is a Vimeo link. Hope somebody knows the answer.

Chris Soucy · February 3rd, 2012, 05:23 PM

Hi, Edsard............

Did you have both the shutter speed and the aperture fixed for this shot? White balance?

What's interesting (on my screen at least) is that most of the flickering seems to be perfectly in time with the strobes firing on both right and left of the performers.

Not having the camera, anyone know of anything else that can simply go "walk about" unless it's told not to?

OR, given the speed with which the lighting was changeing, is this a symptom of the dreaded CMOS "flash" problem? (there, just to show my ignorance - is it a CMOS sensor?).

Best I can do for now.

CS

Matt Ford · February 3rd, 2012, 05:39 PM

So does this happen under normal lighting? or just under rapid stage strobes?

Edsard Keuning · February 4th, 2012, 04:27 AM

Everything was fixed, nothing was set on Auto.

As far as i know the strobe wasn't used in this shot. Everything that you see flickering are moving lights. (The strobe overthere is so strong that you can't miss it)

I have a feeling it is being caused by the refresh rate of LED lights and thats why i tried different Hertz settings.

I also have an XH-A1 and that camera didn't had the problem so i guess its the CMOS sensor that causes this problem.

@matt
I've also seen it flickering in my room but i didn't record that

Matt Ford · February 4th, 2012, 08:39 AM

Ok. I shot for 6 weeks in the US on a PAL 305 last summer. The 2 occasions I had problems were firstly industrial lighting, and tweaking syncro solved that one. The other issue which I think you are having is flicker reduction banding during under exposure. The EX3's would do this also. I was shooting a guitar player and when I went in close to his hands on his very black guitar I got this distinctive banding, as I was shooting PAL and moving locations at speed I had FR on. A quick google took me to a Sony forum and the solution. These sensors really need good exposure especially if shooting with high gain and keep FR off. Do some tests and let us know but nail the exposure!

PS the lights that are flickering in your shot are so fast that is what we mean by strobing, they are not the long burn pulse of old they are high speed short duration, and there are several which will give a strobe affect.

Edsard Keuning · February 4th, 2012, 09:26 AM

I also noticed it happens more when I'm zoomed in. The demo shot was also shot zoomed in at like 70%.

I'm gonna do some more tests in the next weeks. But if i understand you correct there is nothing to do about this problem if you don't have enough light. I only shot at 3dB gain. I'm gonna try if it makes any difference when I'm shooting at 0 or -3dB.

When i find out more I'll make another post. It could take a while since I'm not at these locations every day ;-)

Matt Ford · February 4th, 2012, 04:01 PM

Dont be afraid of gain up to 12 db in this kind of situation, exposed correctly the noise/grain is ok, atmospheric even. Exposure is the key!

Edsard Keuning · February 4th, 2012, 09:26 PM

I'm allergic for noise ;-), but I'll make some test shots with different gain settings.

Thanks for the info!

Chris Dickinson · February 14th, 2012, 09:50 AM

Yup, looks to me that its a problem with frequency of the flashing light v's the CMOS. I really don't know what the point of flicker reduction is bcs whenever I've tried it, it's caused flicker..! So keep that off...

One idea may be to shoot at a slower shutter speed of 1/25th... might help to smooth things out a bit...

You may also have to experience with camera angles, fields of view etc, to find the best compromise.

Some problems we can't solve, we can only minimise.

Cheers,

Chris

Uli Mors · February 21st, 2012, 10:40 AM

It COULD stand in relation of LED Light (likes to flicker at 60Hz) vs. 50Hz recording CMOS.

Always when I film stages I ask the light engineer to go thru all light scenes while Light/Soundcheck.
Use a small 9" (or bigger ) monitor to review, small lcd screens also tend to calm down flickering problems.

br

ULi

January 22nd, 2012, 06:02 AM	#1
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Flickering images Hi, I own the xf300 since a couple of days now. And when i'm filming there is flickering "banding" visible. (See sample) I tried playing with the hertz setting. Arround 50 since i'm living in a PAL area, but also 60 and some lower values. However it doesnt seem to help. I also tried filming with different CP files, flicker reduction turned on and off but nothing removes these bandings. I hope you guys have some tips. Check the file overhere. Its raw straight from the camera hotfile.com/dl/142955493/f89c4e6/AA020601.MXF.html

January 27th, 2012, 09:31 AM	#2
Chris Dickinson Regular Crew Join Date: Dec 2008 Location: Singapore Posts: 38	Re: Flickering images Hi - can you post something on Vimeo as that would be easier to view rather than expecting us to download stuff. Cheers, Chris __________________ Chris D www.chrisd.tv

February 3rd, 2012, 04:26 PM	#3
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Re: Flickering images I uploaded it to a download site because vimeo compresses the material. This way i can show the raw footage

February 3rd, 2012, 04:31 PM	#4
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Re: Flickering images Here is a Vimeo link. Hope somebody knows the answer. Untitled on Vimeo Last edited by Edsard Keuning; February 3rd, 2012 at 05:19 PM.

February 3rd, 2012, 05:23 PM	#5
Chris Soucy Inner Circle Join Date: Feb 2007 Location: Fairfield, Dunedin, New Zealand Posts: 3,691 Images: 18	Re: Flickering images Hi, Edsard............ Did you have both the shutter speed and the aperture fixed for this shot? White balance? What's interesting (on my screen at least) is that most of the flickering seems to be perfectly in time with the strobes firing on both right and left of the performers. Not having the camera, anyone know of anything else that can simply go "walk about" unless it's told not to? OR, given the speed with which the lighting was changeing, is this a symptom of the dreaded CMOS "flash" problem? (there, just to show my ignorance - is it a CMOS sensor?). Best I can do for now. CS Last edited by Chris Soucy; February 4th, 2012 at 02:59 AM.

February 3rd, 2012, 05:39 PM	#6
Matt Ford Regular Crew Join Date: Dec 2010 Location: London Posts: 53	Re: Flickering images So does this happen under normal lighting? or just under rapid stage strobes?

February 4th, 2012, 04:27 AM	#7
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Re: Flickering images Everything was fixed, nothing was set on Auto. As far as i know the strobe wasn't used in this shot. Everything that you see flickering are moving lights. (The strobe overthere is so strong that you can't miss it) I have a feeling it is being caused by the refresh rate of LED lights and thats why i tried different Hertz settings. I also have an XH-A1 and that camera didn't had the problem so i guess its the CMOS sensor that causes this problem. @matt I've also seen it flickering in my room but i didn't record that

February 4th, 2012, 08:39 AM	#8
Matt Ford Regular Crew Join Date: Dec 2010 Location: London Posts: 53	Re: Flickering images Ok. I shot for 6 weeks in the US on a PAL 305 last summer. The 2 occasions I had problems were firstly industrial lighting, and tweaking syncro solved that one. The other issue which I think you are having is flicker reduction banding during under exposure. The EX3's would do this also. I was shooting a guitar player and when I went in close to his hands on his very black guitar I got this distinctive banding, as I was shooting PAL and moving locations at speed I had FR on. A quick google took me to a Sony forum and the solution. These sensors really need good exposure especially if shooting with high gain and keep FR off. Do some tests and let us know but nail the exposure! PS the lights that are flickering in your shot are so fast that is what we mean by strobing, they are not the long burn pulse of old they are high speed short duration, and there are several which will give a strobe affect.

February 4th, 2012, 09:26 AM	#9
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Re: Flickering images I also noticed it happens more when I'm zoomed in. The demo shot was also shot zoomed in at like 70%. I'm gonna do some more tests in the next weeks. But if i understand you correct there is nothing to do about this problem if you don't have enough light. I only shot at 3dB gain. I'm gonna try if it makes any difference when I'm shooting at 0 or -3dB. When i find out more I'll make another post. It could take a while since I'm not at these locations every day ;-)

February 4th, 2012, 04:01 PM	#10
Matt Ford Regular Crew Join Date: Dec 2010 Location: London Posts: 53	Re: Flickering images Dont be afraid of gain up to 12 db in this kind of situation, exposed correctly the noise/grain is ok, atmospheric even. Exposure is the key!

February 4th, 2012, 09:26 PM	#11
Edsard Keuning New Boot Join Date: Jul 2011 Location: Groningen, Netherlands Posts: 10	Re: Flickering images I'm allergic for noise ;-), but I'll make some test shots with different gain settings. Thanks for the info!

February 14th, 2012, 09:50 AM	#12
Chris Dickinson Regular Crew Join Date: Dec 2008 Location: Singapore Posts: 38	Re: Flickering images Yup, looks to me that its a problem with frequency of the flashing light v's the CMOS. I really don't know what the point of flicker reduction is bcs whenever I've tried it, it's caused flicker..! So keep that off... One idea may be to shoot at a slower shutter speed of 1/25th... might help to smooth things out a bit... You may also have to experience with camera angles, fields of view etc, to find the best compromise. Some problems we can't solve, we can only minimise. Cheers, Chris __________________ Chris D www.chrisd.tv

February 21st, 2012, 10:40 AM	#13
Uli Mors Major Player Join Date: May 2006 Location: Germany Posts: 565	Re: Flickering images It COULD stand in relation of LED Light (likes to flicker at 60Hz) vs. 50Hz recording CMOS. Always when I film stages I ask the light engineer to go thru all light scenes while Light/Soundcheck. Use a small 9" (or bigger ) monitor to review, small lcd screens also tend to calm down flickering problems. br ULi