HELP! Need to de-flicker footage!!

[Mark Smith]

Were you shooting in the US or some country outside the US?

[Jenn Lindsay]

Thank you for helping. I was shooting in Greece.

My next shoots are in Uganda and Rwanda.

Thank you!!!

http://www.JennLindsay.com
iMac 27-inch, 3.5 GHz Intel Core i7. 4GB GPU.
FCPX

[Mark Smith]

Ok here’s the deal:

Where you went wrong- In Europe which includes Greece, the power line frequency is 50hz. In the US , Japan and some South american countries the power line frequency is 60Hz. YOur shutter speed of 1/120 would have worked in the US but NOT in a country with 50hz power line frequency. Fundamentally there is a relationship between power line frequency and shutter speed in video and film. The shutter speed must be a whole number multiple of the power line frequency. So in Greece the power line frequency is 50 so shutter speeds of 50 (50/50), 100 (100/50) 150. (150/50) would work . Your shutter speed was 120 which is not a whole number multiple of 50 but rather 2.4 *50 hence you have the flicker problem caused by phasing between the shutter frequency and the power line frequency.

If you want to shoot 23.98 in the other countries you are going to visit, set your shutter to either 1/50 or 1/100 and you should be good to go. This frame rate& shutter speed combo possible with the C100. Problem solved.

In Rawanda you may still get some subtle flicker because I find that power line frequency is often poorly regulated in some 3rd world countries, so 50 hz may actually be 49.8 hz or something close but not exactly 50. Florescent bulbs may also be a problem as they are often used way beyond their service life and develop flicker and pulsing in their old age.

[Joe Marler]

[Jenn Lindsay] “C100 Mk II to shoot a bunch of footage and interviews in rooms with halogen lights. I saw the flicker in the monitor and did some on-site googling, and turned my shutter speed to 1/120 and put on the “clear scan”…I was shooting in Greece….My footage is shot at a 23.98 frame rate”

Greece’s utility grid is 50Hz, so your shutter speed should have been 1/100. That will take care of many problems. However I think Clear Scan might override this and allow dialing the shutter speed smoothly up and down. Depending on how that was set it could help or hurt.

If the lighting was halogen they were probably 50Hz. Increasingly a problem is LED lighting which uses Pulse Width Modulated (PWM) dimming that can cause problems at various shutter speeds. For those Clear Scan might be appropriate, assuming you have time on set to shoot test footage and review it.

To fix the problem after it’s happened is difficult. The only tool I’ve seen that fixes a wide range of flicker and banding problems is Digital Anarchy’s Flicker Free. It’s expensive but relative to the cost of re-shooting, it’s cheap. It works well but is very compute-intensive and slow to run. https://www.digitalanarchy.com/Flicker/main.html

[Jenn Lindsay]

This is so helpful; thank you.

Out of curiosity, and professional necessity,
what are the ideal halogen light settings in the USA?

http://www.JennLindsay.com
iMac 27-inch, 3.5 GHz Intel Core i7. 4GB GPU.
FCPX

[Jenn Lindsay]

OK, maybe I will have to invest in that because I can’t go back and reshoot the footage. Dammit. I really hope it works.

http://www.JennLindsay.com
iMac 27-inch, 3.5 GHz Intel Core i7. 4GB GPU.
FCPX

[Mark Smith]

Here is another tip to kill off flicker when you shoot. This is especially helpful in those third world places where power line frequency is poorly regulated and or power is being provided by generators.

Set up a shot with the lighting you are going to use. Put something white in the frame where it is lit. Call up the waveform monitor on the camera’s LCD screen and observe the white something you put in the frame in the light. If you see the white area on the waveform ‘breathing” which is to say the white level is moving up and down slightly with a regular frequency , then your shutter speed and power line frequency are out of sync. You can use clear scan function to shift the shutter speed in small increments either up or down until the breathing stops. At this point your shutter speed and power line frequency are in sync and you won’t have flicker.

In the US where power line frequency is 60 hz your shutter speeds could be 1/30, 1/60, 1/120, etc.

[Jenn Lindsay]

Mark, thank you SO MUCH for taking the time to help me!

I will try the white object trick. Am I supposed to just leave clearscan and auto flicker reduction on all of the time? Also, clearscan has just an on/off setting, right?

Is there some sort of website where I can find out standard Hz in countries where I’m filming? On the docket after Uganda/Rwanda are Norway, Sri Lanka, the US and the U.K./Ireland.

If you have any thoughts on ideal frame rate I’m happy to hear them. It seems FCPX prefers 29.98 but I don’t know how that interacts with shutter speed.

Do you agree that my only hope for de-flickering in post is the costly plug-in?

So many questions. I appreciate your patience.

Thank you again.
Jenn

http://www.JennLindsay.com
iMac 27-inch, 3.5 GHz Intel Core i7. 4GB GPU.
FCPX

[Jeff Kirkland]

The easiest way to find the power frequency in any country is google. Something like “Sri Lanka power Hz” should get the result you need. I think the U.S. is your only destination that’s not 50hz.

I’ve not used a C100 but when you turn clearscan on, you should also be able to set the frequency. Clearscan on any camera essentially lets you set odd frame rates to minimise flicker so if say 1/50th isn’t working you can dial in something like 1/51.2, etc.

—-
Jeff Kirkland | Video Producer & Cinematographer
Hobart, Tasmania | Twitter: @jeffkirkland

[Mark Smith]

Here’s how I would approach your situation.
If you are in a 50hz power frequency country
1) set your shutter speed to 1/50 and check your picture for flicker under the lighting conditiond you’ll use. If you don’t see flicker then you are good to go.

2) If you do see flicker,Some times the AC power frequency can be a tiny bit off 50.00hz which will cause some phasing (Flicker) issues. This is a bit of a gray area which you may or may not be able to get perfect so be forewarned. Clearscan can help here but its really hit or miss. THis is where the white chip test can be of help though it can be hard to discern especially if the power line frequency and the shutter speed are very close – for example if the power line frequency is 49.9 Hz and the shutter speed is 1/50 the phasing or rise and fall of the white card on the wfm will be subtle and you’d have to watch carefully for maybe 30 seconds to see if it was happening.

HERE IS WHERE WE GET OFF INTO THE WEEDS, SO PROCEED WITH CAUTION. Unless you really know what you are looking for I’d default to a 1/50 shutter in 50hz countries and live with a tiny bit of flicker.
If the 1/50 shutter speed has very subtle flicker you can choose to accept it as it is very subtle or try to dial it out with clear scan. TO dial it out with clearscan first you turn on clear scan then use the function button to activate the shutter speed. Start with a shutter speed of 1/50 and then you can go up or down in fractions of a hz with the jog button. So you might go from 1/50 to 1/50.2 for example and check to see if the flicker is more or less pronounced, the goal being to find the shutter speed with the least flicker. I would not stray more than 1 Hz up or down from 1/50 because its unlikely the power frequency is THAT far off. So the range I would try would be shutter speeds between 1/49 and 1/51. All this said, tuning shutter speed with clear scan may not be perfect either, you may get lucky and find a setting that is perfect or just find settings that are closer to perfect but just a teensy bit off. Again I disclaim- we are off in the minutiae zone here.

3) I have a C300MK2 which apparently does not have “auto flicker reduction” so I can’t weigh in on that . The C100 manual was not particularly informative about this function so I’ll defer to anyone else here.

4) See this page for info about AC power in each country.
https://en.m.wikipedia.org/wiki/Mains_electricity_by_country

5) Shooting 1/120 shutter in Greece must have produced some major flicker . If you stick 1/50 in your 50hz countries you should be in good shape or so close that it really won’t matter that much.