Re: My "Days of Thunder" project

I've shot race cars for many years. 60i is actually the way to go with the shutter set at either 1/60 or 1/250. I would recommend that you try several different combinations, but remember that all NTSC TV is shot at 29.97 interlaced.

The shutter is almost always left at 1/60. If you are following the cars, you want the background to blur naturally. As you increase the shutter speed, the wheels will probably be the first thing that looks stuttery.

Try this for an experiment. Set your camera up and aim it at an ordinary house fan, set on low, med and then high. Then, increase the shutter speed and do the same.

Here are some hard numbers to consider: A NASCAR stock car normally uses a 3.90 rear end gear. They run 8000 rpm at 200mph, so... at 8000rpm (200mph) the axles are turning 2000 rpm or 33 revolutions per second. At 30 frames per second, your wheel should almost appear like it's not turning at all. However, because the shutter is automatically defaulted to 1/60 of a second, a still frame will have the wheel turning throughout the frame. Now, if you dial the shutter to 1/2000 of a second, you will see a completely different picture. the wheel will look like it's turning very slow.

That fan I talked about should be turning at 1850 rpm when it's on high (in the USA). At 1850, the fan blades are tuning about the same as those stock car wheels. Put a mark on one of the blades for even more fun.

When we put cameras in the drivers compartment of off-road trucks, we would set the shutter higher so we could see the mud fly instead of a bunch of blurs.

A word of Caution: As much as you'll want to, do not put your fingers in the spinning blades.

In lesson #2, we'll talk about shooting the muzzle blast on a machine gun.

Steve Wargo
Tempe, Arizona
It's a dry heat!

Sony HDCAM F-900 & HDW-2000/1 deck
5 Final Cut (not quite PRO) systems
Sony HVR-M25 HDV deck
2-Sony EX-1 HD .