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Frame rate to capture bullet?


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#1 Matthew Rogers

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Posted 08 February 2011 - 10:22 PM

Hey gang, I am possibly going to do a job where you will see a bullet entering an object. I haven't found out how slow they want it yet, but am going ahead and getting some ideas so I can be ready to tell them what we will have to do to capture what they want. All I've been told is they want to see objects being hit by a bullet. I am thinking I should be aiming for 6000 to 10000 frames per second. Am I anywhere close or crazy off?

Matthew
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#2 Adrian Sierkowski

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Posted 08 February 2011 - 11:17 PM

I'm pretty sure Vision Research has some clips up of bullet impacts which list the FPS. Not 100% though; but yeah, very very high speed.
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#3 Mark Dunn

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Posted 09 February 2011 - 11:43 AM

I don't know your muzzle velocity (presumably you can find out) but assuming it's around 800 m/s yes, around the 10000 mark. That's the highest rate we needed to use for ballistic research a while back. The bullet will still move 8cm. per frame, though, even then.
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#4 Mitch Gross

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Posted 09 February 2011 - 11:51 AM

It depends on the size of frame, how many frames of action in which you wish to see the bullets travel, type of gun for muzzle velocity, etc.

I can tell you that I think your numbers are probably way too low. For most work we find that a frame rate closer to 30,000fps gets the imagery people are looking for. I've even seen 1,000,000fps bullet hit material, which looks way cool.

We have the Phantom v12.1, which can shoot incredibly fast frame rates at HD resolutions. Likely your best bet.
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#5 Diana Fiori

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Posted 02 March 2011 - 04:25 AM

Here is an example of bullet shot at 40 000 fps using Phantom v12 prototype in a clear summer day, lit by sunshine only:



You will probably need several tests before choosing the right speed for your specific needs, depending on bullet type/speed (pistol or rifle) and the amount of powder, available lights or sunshine, required resolution, framing (super-close-ups need higher frame rate), etc.

For certain type of bullets (980m/s or more) even 120 000 fps might still not be enough... Up to about 100 000 fps sunlight can provide you with nice even (and flicker free :)) light source. For higher speed you might need big mirrors (curved/parabolic mirrors are better, as it can concentrate the beam).

If you are aware about the exact camera trigger moment, you can use a time machine: http://www.bmumford....to/camctlr.html

If color image is not a must, you can also have a look into different black&white high-speed camera models. Here is an example of bullets captured up to 1 million fps:


My reply came a bit late... but hope is still helping.

Diana - Phantom technician
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