Flicker at 120fps on 5k

[Mohamed Younis]

Anyone knows how to solve this?

 

[Michael Lindsay]

Solve as in:

Repair the footage?

Make sure it doesn't happen again?

Ps I am assuming you where not shooting with daylight?

 

[Nick Gardner]

Depends on the cause of the flicker. Most likely you need to use a different light source.

 

[Casey Green]

Adjusting the shutter to match the frequency of the flickering light is the typical practice.

If the footage is already shot, then you would have to probably process individual frames. A difficult trick. Also, you could remove the under exposed frames, and live with footage that is not as slowed down. But this would not necessarily work, depending on the pattern of the flicker.

Hope this helps.

 

[Mohamed Younis]

It's like a shutter flicker. I think it has to do with the light source. I was wondering how to make sure it doesnt happen again since it was barely visible on the 5inch display.
Thanks

 

[bjonsson]

This goes to an issue of Time base. 120FPS is technically a safe speed, but when you are using a time base of 23.98, it does not fall into the safe window. Only safe speeds based off a 24.00 time base will be safe. This is true for lighting under both Tungsten (with smaller-filiminted-lights) and HMI - EVEN WITH FLICKER FREE BALLASTS.

I could go off on my soap box on how 23.98 is a compromise - but that's another post

This was brought up a while ago here:
http://reduser.net/forum/showthread...olling-shutter&p=763046&highlight=#post763046

 

[Mohamed Younis]

This goes to an issue of Time base. 120FPS is technically a safe speed, but when you are using a time base of 23.98, it does not fall into the safe window. Only safe speeds based off a 24.00 time base will be safe. This is true for lighting under both Tungsten (with smaller-filiminted-lights) and HMI - EVEN WITH FLICKER FREE BALLASTS.

I could go off on my soap box on how 23.98 is a compromise - but that's another post

This was brought up a while ago here:
http://reduser.net/forum/showthread...olling-shutter&p=763046&highlight=#post763046

so I just need to change my time base to 24fps?
What's wrong with 23.98 though?

 

[Mohamed Younis]

so I just need to change my time base to 24fps?
What's wrong with 23.98 though?

i was using a Kino 4 bank btw

 

[bjonsson]

Mohamed,

After reviewing your posts, I think I have been talking apples and you oranges (we have been mis-communicating). Are you shooting in Eqypt? If so, I believe Egypt uses a 220V, 50HZ system. If this is true, then you should be using a 25fps TimeBase not a 23.98 nor a 24. What made me review, was that you mentioned elsewhere that 100fps seemed to work for you.

So, you should be shooting with a 25 time base, and the safe speeds under flickering light (flourecsents, hmi, some smaller tungsten lamps) will be 1,2, 4, 5, 10, 20,25, 50, 100.

You will NEVER have flicker under the sun.
It runs the same in Eqypt and the US and everywhere else - there is a good lesson for all of us in that fact.


Let me know if that helps
Good shooting!

 

[Stephen Williams]

I shot 120 all day with a time base of 25 , however I used a shutter speed of 200. However I have shot 120 fps on film many times, not even crystal & never has an issue with larger lights.

 

[Mohamed Younis]

Mohamed,

After reviewing your posts, I think I have been talking apples and you oranges (we have been mis-communicating). Are you shooting in Eqypt? If so, I believe Egypt uses a 220V, 50HZ system. If this is true, then you should be using a 25fps TimeBase not a 23.98 nor a 24. What made me review, was that you mentioned elsewhere that 100fps seemed to work for you.

So, you should be shooting with a 25 time base, and the safe speeds under flickering light (flourecsents, hmi, some smaller tungsten lamps) will be 1,2, 4, 5, 10, 20,25, 50, 100.

You will NEVER have flicker under the sun.
It runs the same in Eqypt and the US and everywhere else - there is a good lesson for all of us in that fact.


Let me know if that helps
Good shooting!

Film is 24fps everywhere I think. So I should change the timebase to 25 and shoot 24fps?
You seem to be right about shooting 100.