Shooting blank firing weapons with RED.

[Kevin Rasmussen]

I shot a feature last year that involved a number of action sequences including explosions and blank firing guns.

I had real problems with the rolling shutter when it came to the blank firing weapons, I was prepared for this and figured it might be an issue but on our budget there was little I could do about it. We tried various shutter angles, smaller loads in the blanks, and in the end, I found that if the over all brightness of the image was high enough it minimized the effect of the split screen/rolling shutter artifacts and made the footage usable. When combining a 90 degree shutter and a 1/4 load blank in the full auto weapons for day exteriors, the rolling shutter effect would only be noticeable to a cinematographers eye.

We ended up scrapping half a sequence in a dark tunnel set with a blank firing AK-47 because the drastic lighting change from the muzzle flash was wreaking havoc with the electronic shutter and the split frame effect made the footage un-usable.

I also had numerous problems with the hard drives dropping frames when the cameras where within 15 ft. of an blank firing automatic weapons. This was solved by switching to CF cards, forcing me down to RC36 but eliminating the drop frame issue.

Since we've been greenlit for a sequel to that film, and we'll be using our trusty RED M-X again, I'm wondering if anyone has had similar experiences and whether there are any clever work arounds or solutions to making blank firing guns and RED actually work together?

My first thought last year when prepping was to shoot the gun fight sequences on 2-perf 35mm and now that I've got a budget that can afford to actually go that route it's looking to me like the best option. I guess another other option would be to pump way more light in the darker sets and bring things down in post, treat it like I'm shooting really high speed or something but I still think the muzzle flash from a weapon like an AK-47 is so massive it's still going to end up splitting frames..

I'm feeling the 2-perf 35mm at the moment since I could really use the extra latitude for all our explosion/fireball SFX photography as well.

Thoughts? Suggestions?

Cheers,

Kevin

 

[Alexander Ibrahim]

Was that M or MX that gave you all the fits and such? Have you tried Epic?

I usually shoot stuff with various sorts of beam weapons, all added in post - so I can't really help you too much cause its never come up for me.

 

[John Marchant]

Muzzle flash versus cmos rolling shutter is purely down to the duration of the flash, just as with lightning effects, camera flashes / strobes. Lowering contrast between the flash and the surroundings will make it less apparent, as the flash will be more local in the frame, and hence give you a greater possibility of lucking out with the timing. That said, if you then pull your curves in post to separate the flash intensity from the background, you'll be back at square one, revealing the split across a large area of the frame.

Shutter angle and settings will never truly solve the problem, as the ramp up in brightness from the flash happens fast enough to occur by chance part way through a frame whatever you do...

Contrary to what you might expect, it might be better to go with a blank load thats bigger rather than smaller - it should burn outside the barrel longer and give you a slightly better chance, even though it'll be brighter and larger.

SSD's have you covered now for the shock/vibration side of things, if you can get them

 

[paulherrin]

have you thought about some post solutions to supplement troublesome shots? way cheaper than film, and you don't have to worry about trying to match formats.

 

[Adam S]

You can do a couple of things to capture the full muzzle flash. You can extend the amount of time the shutter is "open" or you can set the camera to have a faster reset time. So the first option is to set your shutter to beyond 180deg, which I'm never a fan of because of the motion blur, but it is an option. Take to 270 or 360 degrees and it should help capture more of the flash.

To make the camera have a faster reset time change the resolution to a lower resolution. Try dropping down to 3k or if that still doesn't help drop to 2k and it shouldn't be a problem.

You're trying to basically sync the muzzle flash to the shutter so that might be why your 90deg shutter may have worked, but try the lower resolutions so you can maintain a standard motion characteristic.

 

[Uli Plank]

I'd second the post solution. Not so hard to do these days, with all those excellent trackers and pretty good re-lighting and particle solutions.

 

[J. Eric Camp]

A little clarification:

Read reset on a sensor level is not affected by capture resolution. It is a fixed value. However the translated skew time to the final image is affected as suggested. Think of it this way:

The front edge of the read reset is moving at a constant speed. Lets call that a car racing across a football field at constant 60mph. A full sensor read is the time it takes the car to get from one goal to the other. Lets call it 8 seconds (to make it analogous to the true ms read reset). A 2k read would be from the 25 yard line to the next 25 yard line. While the cars speed (rolling shutter read reset) did not change, it crossed the sampled area in 1/2 the time because the area is 1/2 the distance.

So windowing in to 2k will give you a smaller window to see rolling shutter effects, the speed of the shutter does not change

 

[Adam S]

Excuse me, yes you are right, the reset time is fixed. But the read time can change based on the resolution/sensor area recorded. I've tested this many times and rolling shutter artifacts are minimized as you lower the area of the sensor being read. So if you don't have the budget or the post personal capable of doing it in post this is a cheap easy solution.

 

[paulherrin]

that would be cool if someone designed a wireless electronic to go inside the weapon of choice to sync it's firing to the camera...

otherwise, post.

 

[John Marchant]

Not very visually stylish, but its worth noting that live rounds make very little muzzle flash compared to blanks - big Arnie-worthy flames are something of a giveaway that nothing's really going on

 

[Kevin Rasmussen]

It was an M-X but hard drive was at fault not body.

We supplemented a good number of the muzzle flashes in post. This isn't really a concern it's very easy to do, the problem is getting the interactive lighting changes of muzzle flashes without getting the split frame effect.
Fixing it in post might be cheaper and easier but if we did everything in post we'd lose the unique lighting interaction of the muzzle flashes, smoke and cartridge ejection which are things that take too much time in post and never look right in the end anyway.

Besides our mandate with these films is to bring back the action feel of the 80's and 90's so every special effect we do is done in camera, no CGI.

I think it's going to be 2-perf 35mm. I remembered reading an article recently about this in AC magazine so I pulled that issue out and read the Sundance 2011 piece for The Devils Double and like I thought DP Sam McCurdy BSC had the same issues I did. His solution was 35mm for action sequences because like me, he didn't want to compromise by shooting a 360 degree shutter or use CGI SFX.

Thanks for sharing your thoughts.

 

[Kevin Rasmussen]

big Arnie-worthy flames are something of a giveaway that nothing's really going on

But boy does it ever look cool

"HOLLYWOOD IS SO INACCURATE! HOW DO THEY WALK AWAY IN MOVIES WITHOUT FLINCHING WHEN SOMETHING EXPLODES BEHIND THEM!??? THERE'S NO WAY!!! I CALL BULLSHIT ON THAT!!" - Will Ferrel

 

[paulherrin]

I understand, not a bad choice. If you've got the budget, I'd say do it... but just remember it is possible to get what you want in post (not just muzzle flashes, but the lighting). With the right team, you'd never tell the difference. But it would also be nice to not have to worry about that at all. Happy shooting

 

[Michael Romano]

I've had to splice frames together with still camera strobe flashes done poorly on set before. Taking the top of one frame and bottom of the next, its a real nightmare and is noticeable in even some of the best circumstances. Shoot on film if the 360Degree shutter isn't going to work for the sequence. Do it right! Lighting up a set with muzzle flashes in post has few truly happy endings outside of the most talented VFX houses, and sometimes not even then.