HPX250: flickering footage I just can't figure out

pkakert

pkakert

Member
I am getting flickering footage using my HPX250 and I can't figure it out. I have been shooting 1080i AVC-Intra 100/60i, shutter off. I see no flickering in the viewfinder or on my LCD on the camera, but when I view the footage on my MacBook Pro, there it is. I've tested other settings running the gamut down to 720p30 DVCPRO HD and it's always there. I'm on the road in the middle of a 3 week shoot and this is a problem. Also, I choose 1080i AVC-Intra 100 because I thought it was a higher quality than DVCPRO HD, but the footage I am seeing looks grainy and not better than what I normally see with DVCPRO HD 720p30. Looks great on the LCD and viewfinder when I'm shooting, but once on the computer, not crisp.

I've shot for years on my HVX200 and almost exclusively shot DVCPRO HD 720p30 and have never had a similar issue. I am lost on this and hope someone can help me out.
 
In a few shots in warehouses, I thought that was the problem, but most shots are not under fluorescent lights. I'm in my hotel now and trying different settings and no fluorescent lights in here and I get the flicker. Only time I don't get it is in PN mode or when I switch to 50i instead of 60i. I'm lost.

The Panasonic tech support says since it looks fine in my HPX250 LCD that the footage is fine it's just a problem with my MacBook Pro displaying the footage. I would love to believe that cuz it means I just didn't shoot 10 days of garbage.

Open to any ideas.
 
Are you in a place that uses 50 hz power if so even normal lights will flicker on video shot in 30p
 
Yes, in Europe. I had not realized that. So if I shoot at 50i instead of 60i, would that eliminate the flicker?

Any way to salvage the footage I shot at 60i that flickers?

It's still odd to me that it doesn't flicker when I play it back on my HPX250's LCD monitor, but since it flickers once I get it on the computer, I suppose it's there and there is no getting rid of it???
 
Yak said:
Final cut 7 has a Flicker filter that can help a bit bit.
Click to expand...

*facepalm*

That's not what the Flicker Filter is for. You use that on an image that might have sharp edges or fine lines which may induce a flickering effect on a CRT screen. Sharp text or graphics also induce flicker. I use the Flicker filter a lot when I make SD DVDs.

Flickering lights in your footage cannot be corrected, sorry. Use syncro scan in PAL countries to dial in a shutter that cancels it out.
 
pkakert said:
Yes, in Europe. I had not realized that. So if I shoot at 50i instead of 60i, would that eliminate the flicker?

Any way to salvage the footage I shot at 60i that flickers?

It's still odd to me that it doesn't flicker when I play it back on my HPX250's LCD monitor, but since it flickers once I get it on the computer, I suppose it's there and there is no getting rid of it???
Click to expand...

Well, it depends on how you are editing it and where you are editing it, as well as where your footage needs to be distributed to. If you shoot 50i, will the 50i flicker when you get back to the US? Because here it's a 60hz cycle... Thus the reason for different frame rates = different power. You could use something to conform the footage to the standard you need, or try dropping it on a 50i timeline and see if that helps.
 
Jarek Zabczynski said:
*facepalm*

That's not what the Flicker Filter is for. You use that on an image that might have sharp edges or fine lines which may induce a flickering effect on a CRT screen. Sharp text or graphics also induce flicker. I use the Flicker filter a lot when I make SD DVDs.

Flickering lights in your footage cannot be corrected, sorry. Use syncro scan in PAL countries to dial in a shutter that cancels it out.
Click to expand...

Thank you for clearing that up. I have used it where 50 hz incandescent lights created a flicker in a shot, while it did not fully remove the flicker the end result did look better but maybe that was due to other factors in the frame.
 
Depending on what you were shooting you may be able to fix or at least reduce the flicker by applying a bit of motion blur or by overlaying a second track of the video offset by one frame and with some transparency applied.
 
UPDATE: I've switched to shooting 50i and it has eliminated the flicker. To be clear, I don't see it in the HPX250 LCD and I don't see it on my MacBook Pro within FCP. Someone posed the question, will it flicker back in the US where electicity/lights run at 60Hz? I'm assuming not because there is no flicker in the footage itself. The only reason this flickered at all was because of the conflict of the HPX's 60i setting and the lights in the scene running at 50Hz (from my limited tech understanding of that). So it was recorded with flicker, the flicker didn't show up dependent upon where or how it was played back. In FCP, I've dropped the footage into a 60i timeline and it's fine. No difference if I also drop it into a 50i timeline. So I'm moving ahead continuing to shoot in 50i and feel confident the footage is just fine. Hope so, anyway.
 
If your final destination is the 60 Hz world and you are expected to release NTSC type footage you should shoot in 60i with the shutter adjusted to the 50 Hz of Europe.
To do this you need to set shutter to syncro scan and test it with a broadcast monitor.
 
You would have to use 1/100 to shoot 60i in a 50hz world under 50hz lights. You can't shoot at 1/50th in 60i, it's impossible; the camera would instead duplicate frames to give you effectively 30p. The shutter speed can never last longer than the duration of a frame.
 
You shot 12fps when at 1/12 and 6fps when shooting 1/6th.

Think about it -- when shooting film at 25p, each frame can only see the sensor for a maximum of 1/25th of a second. After that 1/25-second is gone, the frame moves on and the next frame comes into place.

When you hold the shutter open longer than the frame rate, the camera is forced to duplicate frames. It writes the same frame out multiple times. Go look at your 1/6-sec footage and you'll see that each frame is duplicated 4 times. You got (effectively) 6fps footage a 1/6th-sec exposure.
 
Yes thats correct but to come back to the problem of shooting in 50 Hz world with 30fps or 60i: isnt the right approach to adjust the syncro scan to eliminate flicker? and yes 1/100 would be the best solution but what if you would use syncro scan to shoot in 1/50 sec? If the final product is to be NTSC, would it be possible to use 1/50 sec?
 
If shooting 30p then sure. But you can't shoot 60i/60p at 1/50th, because it will force the camera to 30p anyway. If you want/need the 60i/60p look, 1/100 should work under 50hz lights.
 
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