Correct shutter speed for fast moving cars
 

Hello,

When I use the recommend settings (for 25 fps -> 1/50) the video of fast moving cars is not fluent but like... it was recorded with 10 fps or so. So when I start the recording, the cars at big distance moving fluently, but as they come closer to me, it goes wrong.

Let me show you 2 situation I make films. Sorry about the bad paintbrush knowledge.

Can you suggest a good shutter speed for such situations, please?

Just a few thoughts here.

It depends on the effect you want and how you are distributing.

Cleanest shot would be 720 50p 1/100 PAL, shutter or 60p shutter 1/125 NTSC.

Are you panning with the car or locked down?

If you carefully pan with each car then you could shoot 25p shutter 1/50 PAL, or 30p and shutter 1/60 NTSC. The background will then blur but the car will be clear.

If you are not panning. The cars will blur. You could try a higher shutter speed, it would have a strobing effect.

I would experiment a bit and decide what you like.

That shutter speed is recommend based on narrative film, where the fastest thing happening is someone walking quickly on the screen. As Olaf has stated, the shutter speed must change based on what is happening on the screen.

Thank you Olof. I use tripod, static position, so I am not following any car with the 7d. I shoot in Pal mode, the final result should be 25 fps.

So if I choose like 1/100 the I get fluent move, right ? Is this stobe effect can be seen on daylight, or it is not matter if it is morning or evening ?

Tans, yes try the 720P 50 and 1/100, it will be a lot cleaner than 1080P 25 1/50.

But it may not be exactly what you are looking for so try some faster shutter speeds as well.

There is what is called the 7 second rule for film 24fps. For a clean looking image (minimal blur) it should take 7 seconds for anything to cross the entire frame. So for a clean 50fps 3.5 seconds would be pretty clean. But faster than that and it will still blur.

Just move your hand in front of your face while concentrating on something in the back ground, you will notice the hand is almost invisible, just a blur. But if you move your head or eyes with the hand the hand is sharp and the background blurred. So our eyes do this as well. At least that is how I am wired.

Just go out and try different settings until you find what you like. The above setting will get you started.