The shutter speed rule, again. at DVinfo.net

John McCully · July 25th, 2018, 11:05 PM

The Lumix G9 and the GH5 have a menu item titled ‘Flkr Decrease’ located at ‘MENU motion picture (camera icon) page 2’. The idea, according to the user manual, is that in order to reduce/eliminate flicker artifacts when shooting video the maximum shutter speed can be set. This function is seemingly only available when shooting in other than the ‘Motion Picture’ mode. When this function is set to a value other than 'off' the shutter will not exceed the value set when shooting video. The exposure is then controlled by increasing the aperture (or adding ND filters which is just a pain) whereas when Flkr Decrease is set to off exposure can be controlled by increasing the shutter speed which of course then enables wider apertures for shallower DOF and ‘possibly’ sharper video depending on the lens, perhaps.

I invariably shoot at 60p mostly in very bright sunlight and even at very high shutter speeds I have yet to see the dreaded flicker or striping in the motion picture. I should also mention I rarely seek to obtain shallow DOF but sharp is most often a must.

So, should I ignore the potential flicker or striping problem, select the aperture that enables maximum performance from the lens while controlling exposure with the shutter speed or should I really choose an aperture that enables correct exposure while keeping my shutter speed at 120 at all times, as the old golden rule would have it?

Many thanks for your input

Joe Wickert · July 27th, 2018, 12:04 AM

I'm in PAL format(Australia) so framerate is 25/50fps with shutter speed set at 1/50.

My experience with the GH4 is that setting shutter higher than 1/50 will give nasty flicker when shooting indoors with installed lights.

When i've forgotten my NDs and shot with high shutters I've been disappointed to see nasty brown bands rolling down the screen. They are slow, and faint, so luckily the average viewer does not notice them in standard playback. But if you scrub through the footage in fast forward they are really noticeable and once you've seen them you can't unsee them!

Maybe if you are in sunlight or only using your own lights you might be ok, but we tend to be filming in offices and schools with all sorts of lights on and get interference.

Don't know if it's flouros or other types of lights that cause issues, but it's real and it's ugly!

John McCully · July 27th, 2018, 03:57 PM

Thanks Joe, appreciate your thoughts. After more searching the Internet regarding this topic I have concluded, for now, that it all depends on the subject matter and the shooting conditions. For you and the constraints of varying lighting conditions you say it matters a lot while for me, shooting outdoors in bright sunlight mostly and shooting 60p 4k the subjects being landscapes, wildlife and sailboats out on the water I can not see any flicker no matter the shutter speed I choose.

I shall cheerfully ignore the setting Panasonic has included that enables one to set a maximum shutter speed and continue using the shutter to control exposure, where necessary.

Cheers.

July 25th, 2018, 11:05 PM	#1
John McCully Major Player Join Date: Oct 2003 Location: South Island, New Zealand Posts: 609 Images: 2	The shutter speed rule, again. The Lumix G9 and the GH5 have a menu item titled ‘Flkr Decrease’ located at ‘MENU motion picture (camera icon) page 2’. The idea, according to the user manual, is that in order to reduce/eliminate flicker artifacts when shooting video the maximum shutter speed can be set. This function is seemingly only available when shooting in other than the ‘Motion Picture’ mode. When this function is set to a value other than 'off' the shutter will not exceed the value set when shooting video. The exposure is then controlled by increasing the aperture (or adding ND filters which is just a pain) whereas when Flkr Decrease is set to off exposure can be controlled by increasing the shutter speed which of course then enables wider apertures for shallower DOF and ‘possibly’ sharper video depending on the lens, perhaps. I invariably shoot at 60p mostly in very bright sunlight and even at very high shutter speeds I have yet to see the dreaded flicker or striping in the motion picture. I should also mention I rarely seek to obtain shallow DOF but sharp is most often a must. So, should I ignore the potential flicker or striping problem, select the aperture that enables maximum performance from the lens while controlling exposure with the shutter speed or should I really choose an aperture that enables correct exposure while keeping my shutter speed at 120 at all times, as the old golden rule would have it? Many thanks for your input Last edited by John McCully; July 25th, 2018 at 11:46 PM.

July 27th, 2018, 12:04 AM	#2
Joe Wickert New Boot Join Date: Oct 2010 Location: Sydney, Australia Posts: 22	Re: The shutter speed rule, again. I'm in PAL format(Australia) so framerate is 25/50fps with shutter speed set at 1/50. My experience with the GH4 is that setting shutter higher than 1/50 will give nasty flicker when shooting indoors with installed lights. When i've forgotten my NDs and shot with high shutters I've been disappointed to see nasty brown bands rolling down the screen. They are slow, and faint, so luckily the average viewer does not notice them in standard playback. But if you scrub through the footage in fast forward they are really noticeable and once you've seen them you can't unsee them! Maybe if you are in sunlight or only using your own lights you might be ok, but we tend to be filming in offices and schools with all sorts of lights on and get interference. Don't know if it's flouros or other types of lights that cause issues, but it's real and it's ugly!

July 27th, 2018, 03:57 PM	#3
John McCully Major Player Join Date: Oct 2003 Location: South Island, New Zealand Posts: 609 Images: 2	Re: The shutter speed rule, again. Thanks Joe, appreciate your thoughts. After more searching the Internet regarding this topic I have concluded, for now, that it all depends on the subject matter and the shooting conditions. For you and the constraints of varying lighting conditions you say it matters a lot while for me, shooting outdoors in bright sunlight mostly and shooting 60p 4k the subjects being landscapes, wildlife and sailboats out on the water I can not see any flicker no matter the shutter speed I choose. I shall cheerfully ignore the setting Panasonic has included that enables one to set a maximum shutter speed and continue using the shutter to control exposure, where necessary. Cheers.