Frame Rates/Shutter Speeds/ahh Help Me!

V

VaricamLife

Well-known member
Okay, I'll start off saying I'm not a DP, I'm an editor, so much help is needed. I'm just trying to investigate for the directors as the DP is out of town right now.

Here's the deal, we're shooting a fighter jet cable landing. This thing is coming in at some kind of ridiculous speed. We want to see the cable / hook connection clearly. Right now, even at using the best overcrank we have (with the Varicam) we still get a 'blur' when looking at the footage.

So we're wondering is can this kind of shot be done by a video camera at all? If so what video camera and do it and what kind of settings would we need? If not, I guess that means we're shooting film for this shot?

Cheers and thanks.
 
Well... you're probably pushing the limits of what you can expect a video cam to do. But setting it at 60fps, and then putting the shutter speed absurdly fast (like 1/1000 or 1/2000, or 10 degrees) will get you the crispest still frame you can get.

Film is an option, but most film cameras don't go much faster. You may be looking at needing a high-speed film camera or one of the special-purpose video cameras that can do hundreds and even thousands of frames per second.
 
Thanks

Thanks

Thanks Barry. I guess we'll have to start doing some test real quick here and see what we can get from the Varicam pushed all the way. And of course we want to be as tight as possible on it, so its quite the "whiz past" I have to say. Hopefully we can't find something that works, cause it will be a great shot if we can get it.

cheers.
 
Thanks Mack, I'll pass that along. I did run into that in my searches, but was got scared off frankly because of the web site. Its not umm very inspiring in design for what ought to be a quite high end/expensive piece of equipment.

cheers.
 
Changing the view angle might help. If you're looking dead-on from the side, try hitting it from closer to the rear or front.

If you're already looking from an angle...I've got nothing. :)
 
Just out of curiousity, what would the angle change do to improve chances of getting a clean set of frames of the connection between the cable and hook?

cheers.
 
No, but shooting from a 3/4 angle will keep the hook/cable within the camera's field of view longer, making for a more usable shot that allows the viewer to see what's going on.
 
VaricamLife said:
Just out of curiousity, what would the angle change do to improve chances of getting a clean set of frames of the connection between the cable and hook?

cheers.
Click to expand...

I'm just backward theorizing. If you shoot from a car, for instance, and you want to make things look like it's going fasterr than it really is, shoot directly out the side of the road. It just whizzes by, a big blur.

Shooting at an angle slows things down. Not really, but like dcarstens said, things are in view longer, making it seem slower, giving the viewer a better chance to see what is going on.

It probably wouldn't prevent blurring of the hook, etc., but it will provide more visual information for the brain to interpret what it's seeing.

No harm in trying it, anyway. :)
 
I think the angle of view change will be your best bet. Lets say you set up the camera near the bridge on the carrier. As the plane comes in, your shot will be almost straight on. As it approaches the cable it will be easier to track the hook from that angle. It may require a quick zoom out and focus adjustment. Being that you dont know which cable the hook will grab it would be hard to set up at 90 degrees to the point of hook up and if you did manage to get a shot from that angle you will almost certainly have a blur as you would need to pan very quickly. Check out the Discovery Wings channel. I remember seeing that sort of thing on one of their shows.
 
Is the blur in your STILL frames? Or does it appear when you playback at speed??

Your problem is that you need an exposure that is "very fast" in a camera technology that has practical limits on exposures.

She short answer: You need to "strobe it" with a very high EFFECTIVE shutter speed (faster even than overcranking) which requires broad daylight and/or megawatts of light.

You can also use a "strobing flash" at a smaller aperture (to reduce the ratio of natural light) to expose your overcranked film without upping the shutter speed. The reason this works is that a f/16 "strobe flash" can have a duration as brief as 1/2000 sec. If your natural/ambient meters at f/11, and you setthe strobe to meter f/16, then the natural light will still give a good background and other details, but the hook, while still showing SOME blur (1 stop underexposed natural light) will POP at the proper exposure from the strobe.

Now for the "practical" answer: Unless you are going to slow or freeze these frames, the motion blur of overcranked footage should entirely undetected by the eye of 95% of the viewers.

Is this a specific effect that is integral to the scene? and to what degree?
 
VaricamLife said:
Just out of curiousity, what would the angle change do to improve chances of getting a clean set of frames of the connection between the cable and hook?

cheers.
Click to expand...

it would change the apparent speed of the hook ACROSS the frame.

At a 45' angle, the apparent speed would be reduced to .707 of the actual speed (due to trigonometry).

Now for the bad news. At exactly 90', the depth of field is less irrelevant (as the object is not moving towards the camera (although for a landing it may vary from take to take, so you should still allow a fair bit of leeway). But at 45' the object is now moving TOWARDS the camera at the same speed it's moving ACROSS the frame, making the WIDE OPEN aperture needed to get such a shot (high shutter speed) a real challenge. Although, artistically, it sure might be cool if the hook were to COME INTO FOCUS as it catches the wire.
 
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