Explosions!

[Forrest Burger]

I have a client that potentially wants to do a video testing a new product. It would involve submitting the product to explosive forces like improvised explosive devices (IED's) and gunfire.

How might I expect the EX series cameras to perform under these circumstances, taking into account the rolling shutter?

Thanks,

Forrest

[Noah Kadner]

Well the EX1 is tougher than a tape based camera but it's not bullet proof or hardened. Anything major would probably wreck it. Have you considered a more specialised industrial/medical camera system? There are also camera mounts and rigs specifically designed to survive bullets and bombs...

Noah

[Forrest Burger]

Noah,

I think you may have misunderstood my post, or I didn't make myself clear enough. The idea is to document how the client's product would withstand an explosion or being hit by gunfire.

The EX1 or EX3 would be a safe distance away, even behind plexiglass if need be. The test would be performed during the day. I'm just wondering how the camera's rolling shutter would perform in this scenario.

Forrest

[Daniel Weber]

Fast moving subjects don't lend themselves well to rolling shutters. You might want to go for a Progressive camera with a traditional shutter.

Something that shoots 720p60 would be great for that type of thing. It would give you great slo mo shots.

Daniel Weber

[Bob Grant]

Mentioned this in another sub forum here but worth repeating given the topic.

We rented an EX1 to a client for documenting a car bomb and suicide bomber.
Footage was shot at 720p60. Looking at it frame by frame the car / dummy was there in one frame and gone the next. Almost no flash or flames were visible. Modern explosives are incredibly fast and need a huge number of fps to really catch what's going on, even 1,000fps might not be enough depending on what you're trying to show. If all you want to show is effectively before, the event and what remains then the EX1 would be plenty fast enough.

On the other aspect, our EX1 didn't suffer and it was fairly close to the action. If the operator is safe so should the camera.

[James Brill]

I would recommend trying to rent a phantom camera in all honesty. It is going to be a difficult shoot no matter what.

[Forrest Burger]

Thanks, Bob.

The intent is to show the before and after as part of a product marketing video, basically to show the success of the product after being exposed to explosives. I've done these kinds of shoots several times with CCD based HDV cameras with fairly good success, but I don't have own those cameras any more, just CMOS cams.

My concern is the "half flash" effect from the rolling shutter that I've seen from video samples that contain flash photography. My thoughts were in fact to shoot it at 720 60p at fairly high fps.

Forrest

[Shaun R Walker]

Originally Posted by James Brill

I would recommend trying to rent a phantom camera in all honesty. It is going to be a difficult shoot no matter what.

I agree. A Phantom V10 can shoot 2000fps at 720p or 1000fps at 1920x1080. I can give you a contact if you like.

[Michael Maier]

I shot an action short film with the EX1 and it was a pain to see the muzzle fire of the blank guns. It took several takes. Sometimes there was no muzzle flash at all. I guess you need to be lucky that the shot/gun discharge happens at the exact right timing with the rolling shutter. But after several takes we did manage to record the muzzle flash in camera.
We were rolling 1080 at 24p. I haven't tried 60p, but I will next time around to see if it does any better.

[Noah Kadner]

Most definitely get a Phantom HD. You can certainly make an ok video about explosions with the EX1 but if you really want to show the true impact in a clear way, there's nothing better suited to 1000fps with a Phantom. Rentable easily in NYC and LA at Abel Cine Tech, and elsewhere.

Noah

[Bob Grant]

Originally Posted by Forrest Burger

Thanks, Bob.

The intent is to show the before and after as part of a product marketing video, basically to show the success of the product after being exposed to explosives. I've done these kinds of shoots several times with CCD based HDV cameras with fairly good success, but I don't have own those cameras any more, just CMOS cams.

My concern is the "half flash" effect from the rolling shutter that I've seen from video samples that contain flash photography. My thoughts were in fact to shoot it at 720 60p at fairly high fps.

Forrest

Looking through the explosion footage I really didn't notice anything wierd happening to the image at all. The very fast stuff is so fast that the motion blur from the shutter would mask it anyway. Also with modern explosives there's very little flash at all, checkout footage at Cordin to see what I mean, even at 1,000,000fps you don't see much if any flash.
The same goes for guns, most if not all of the powder burns before the bullet leaves the barrel.
What could happen though is the blast wave rocks the camera causing a few jello frames. Then again, the jello frames could add a certain impact that might look quite effective in this instance.

[Forrest Burger]

Originally Posted by Bob Grant

Looking through the explosion footage I really didn't notice anything wierd happening to the image at all. The very fast stuff is so fast that the motion blur from the shutter would mask it anyway. Also with modern explosives there's very little flash at all, checkout footage at Cordin to see what I mean, even at 1,000,000fps you don't see much if any flash.
The same goes for guns, most if not all of the powder burns before the bullet leaves the barrel.
What could happen though is the blast wave rocks the camera causing a few jello frames. Then again, the jello frames could add a certain impact that might look quite effective in this instance.

Thanks for the info, Bob.

Forrest

[Charles Young]

You need to have very specific information about the entire setup. The camera, EX1 or other, needs to have protection or distance from the blast. Zoom is good in this case. Long focal length, way far away. Inherent in the EX1's sensor is anti-blooming, that will help. I will suggest bright daylight, direct sunlight, and the fastest shutter possible to get a good exposure.

Exactly what is it that is your main interest in the scene. How fast is it traveling and how far away is it. How long will it take to pass your field of view. What is the resolution you need on the subject. All these issues need to be considered.

The EX1's 1/2000 is not the greatest for fast moving things. 1/10,000 is typical.

Originally Posted by Forrest Burger

I have a client that potentially wants to do a video testing a new product. It would involve submitting the product to explosive forces like improvised explosive devices (IED's) and gunfire.

How might I expect the EX series cameras to perform under these circumstances, taking into account the rolling shutter?

Thanks,

Forrest

[Forrest Burger]

Originally Posted by Charles Young

You need to have very specific information about the entire setup. The camera, EX1 or other, needs to have protection or distance from the blast. Zoom is good in this case. Long focal length, way far away. Inherent in the EX1's sensor is anti-blooming, that will help. I will suggest bright daylight, direct sunlight, and the fastest shutter possible to get a good exposure.

Exactly what is it that is your main interest in the scene. How fast is it traveling and how far away is it. How long will it take to pass your field of view. What is the resolution you need on the subject. All these issues need to be considered.

The EX1's 1/2000 is not the greatest for fast moving things. 1/10,000 is typical.

As I posted earlier, I've done several of these kinds of shoots in the past, most often with multiple cameras, so I'm very aware of protection, distance, shutter speeds, etc.

I'm really just interested in the performance of the rolling shutter on an EX1/EX3 in this particular scenario since I may be purchasing one in the near future.

Forrest

[Dave Morrison]

Doesn't the Long GOP file structure of our EX1's have as much to do with missing the "peak of action" issue as does the rolling shutter? I may be completely off-base on this, but I'd swear that I saw or read an explanation about Long GOP and how it has to "fill in" info between I-frames and if the, e.g. explosion, happens between I-frames, then the camera might not have the image? Somebody with a big brain....please set me straight on this. ;)