Weird scanning issue on Muzzle flashes...

[bzada]

Just shot a couple days with the Red Cam and for the most part got great looking ftg.
One odd thing that did happen was on some of our gun fire/muzzle flashes. On some of the shots, the flash actually recorded, but about 40-50 lines above the muzzle. So the camera basically moved the location of the flashes up, but still recorded what it thought was a correct picture. So it did not just record a partial flash, it actually moved the entire star shaped flash up.

It did not do it on every shot, but probably on 30 percent.

I'll post stills in a bit when I get the ftg. transcoded.

It didn't ruin anything for us but I could see how this could be an issue on another shoot.

 

[Jeff Kilgroe]

RED only records what it sees optically. It can't just defy the physical laws of the universe and transpose a muzzle flash to a different location in your image. We have to ask just what type of firearms were being used, their angles to the camera, etc.. Many high power firearms actually produce visible muzzle bursts in airspace a few inches in front of the muzzle break. Could be other things too such as flare properties of the lenses being used. But post your stills, I'm curious to see what you're talking about.

 

[Kyle Presley]

Could it be a rolling shutter issue?

 

[Harry Clark]

My guess would be rolling shutter for sure.
I'm sure the muzzle flash exists above and below the height of the muzzle as well as at its level.
The rolling shutter defect simply would not allow the whole thing to appear in frame.
But posting a still might help clarify.
Cheers,
Harry

 

[Steve Sanacore]

I didn't see Che yet, but didn't they have lots of muzzle flashes in those two films?

 

[Ryan Manes]

I don't recall any funky muzzle flashes in Crossing the Line.

 

[Charles Angus]

They were probably done in post...

 

[Jeff Kilgroe]

There were indeed split-frame muzzle flashes in Crossing the Line. And no, they were not done in post. I asked that same question over a year ago. I still have never seen the full CTL short -- only the 2K ProRes trailer version.

 

[J. Eric Camp]

\So it did not just record a partial flash, it actually moved the entire star shaped flash up.

Not rolling shutter if the whole flash is there with no hard edge cutting it.

Sounds like a combination of the muzzle venting in the particular barrel and the physics behind "kick."

 

[Dan Hudgins]

Re-coil?

Re-coil?

Just shot a couple days with the Red Cam and for the most part got great looking ftg.
One odd thing that did happen was on some of our gun fire/muzzle flashes. On some of the shots, the flash actually recorded, but about 40-50 lines above the muzzle. So the camera basically moved the location of the flashes up, but still recorded what it thought was a correct picture. So it did not just record a partial flash, it actually moved the entire star shaped flash up.

It did not do it on every shot, but probably on 30 percent.

I'll post stills in a bit when I get the ftg. transcoded.

It didn't ruin anything for us but I could see how this could be an issue on another shoot.

If you have an exposure where the gun goes off, the flash will record like a strobe, but if the hand re-coils back and comes to rest for 1/60sec you will get the flash in one place, and the gun and hand in another, the slight blur of the hand moving quickly on the recoil would not be obvious, maybe.

If you set the shutter to 360 degrees, you may get more of the motion of the hand in the exposure if the hand was in motion before the shot, and right after, that way the flash would be mid way along the blur of the gun moving.

Try locking the gun in a vice and firing it to see if there is no possable motion of the camera or gun the same thing happens.

The camera man may also jerk the camera on the sound of the gun, so lock the camera and gun down to see...

With the shutter to small angles there should be frames without a flash at all, just as happens with movie cameras?

 

[Jarred Land]

Just shot a couple days with the Red Cam and for the most part got great looking ftg.
One odd thing that did happen was on some of our gun fire/muzzle flashes. On some of the shots, the flash actually recorded, but about 40-50 lines above the muzzle. So the camera basically moved the location of the flashes up, but still recorded what it thought was a correct picture. So it did not just record a partial flash, it actually moved the entire star shaped flash up.

It did not do it on every shot, but probably on 30 percent.

I'll post stills in a bit when I get the ftg. transcoded.

It didn't ruin anything for us but I could see how this could be an issue on another shoot.

Im going to state the obvious.. but did you using a real theatrical blank firing gun or just a cheap off-caliber replica pistol... the cheap firearms exhaust out the top of the gun usually ( or the side ) so the flash doesn't actually come from the barrel..

 

[Brook Willard]

Jarred speaks the truth. The $100-off-the-internet 8mm blank guns generally have a completely plugged barrel... resulting in a significant discharge out of the ejection port or breech.

A "true" theatrical weapon [modified from a life firearm with a conical partial barrel plug] will maintain a "real" muzzle flash. That said, there is still a very good chance that a camera [RED, film, otherwise] will miss the muzzle flash... as the camera is only recording half of the time [180˚ shutter]. Particularly since people have fallen in love with the narrow shutter for action sequences, the number of actual muzzle flashes caught on digital/film has decreased [shooting with a 45˚ or 90˚ shutter will result in proportionately fewer muzzle flashes captured when compared to a 180˚ shutter].

 

[tj williams]

Remember the good ole days when the optical viewfinder and spinning mirror shutter, showed you when you were getting the flash.... If you saw it you didn't get it.... since the shutter open equaled not seeing the image during that part of the shutter rotation

 

[Andrew Walker]

I need to do some tests on this when I go out to the desert next time. I was also hoping to see if the original poster was going to post some frames of what he got so we could all see what he's referring to. My problem is that suppressors get rid of most of the flash and sound. Guess I'm going to have to make my weapons loud for a little bit.