PART 5: THE SHUTTER

About 15 years ago when CCD chips were first launched they had a design fault. If the camera was pointed at a bright light, like a car head lamp, a red line (smear) would appear above and below the light source. Eventually the boffins managed to partially solve this problem by introducing a shutter.

Today the red smear has been eliminated by redesigning the CCD chips but unfortunately the shutter has remained as a gimmicky extra.

The shutter speeds available are: 1/3, 1/6, 1/12, 1/25, 1/50, 1/60, 1/100, 1/120, 1/150, 1/215, 1/300, 1/425, 1/600, 1/1000, 1/1250, 1/1750, 1/2500, 1/3500, 1/6000, 1/10,000 (of a second).

With the shutter on, the camera views the scene, the way your eyes would, if it was lit by a stroboscopic light such as at a disco (remember those!). Fast moving objects take on a juddery, edgey look. Take a look at the explosions on Steven Spielberg's Band of Brothers or Saving Private Ryan. You'll see every brick, every clod of earth as it it flies though the sky - that's because a high shutter speed was used. Fast moving objects look much more distinct - but remember that's not how the human eye sees the world - so, your subject will look different, strange, not quite real.

As the shutter speed increases, the amount of light entering the camera effectively decreases, so if you do want to use the shutter ensure you have sufficient light.

DARKER PICTURES<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>> BRIGHTER PICTURES

1/10,000..........1/6000..........1/1000..........1/300..........1/150..........1/100..........1/50

INCREASED PICTURE "JUDDER" <<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>DECREASED PICTURE "JUDDER"

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SETTING THE SHUTTER MANUALLY

Set the AUTO LOCK switch to the middle position
Press the SHUTTER SPEED button and the speed indicator will appear in the viewfinder/LCD screen.
Turn the SEL/PUSH EXEC dial to select the speed you want.

Leave the shutter speed at 50 if you want to see no shutter "effects". Or press the SHUTTER SPEED button again to return to automatic.

Professional camera operators use the shutter for three main reasons:

When shooting sports matches. As the slow motion action replay is played the fast moving ball will appear in sharp(ish) focus rather than a blur.
For interesting visual effects - such as showing the individual water droplets of a fountain.
To reduce flicker when recording a scene with computer screens.

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SHOOTING COMPUTER SCREENS WITHOUT FLICKER

It was originally thought that it was impossible to shoot a "clean" computer screen (ie no rolling black or white bars) with a PD150 and PD170 - because the shutter speed only goes up in chunks ie 50, 60, 100, 120, 150, 215, etc. Non of which are any use in getting a computer screen without flicker. However, some bright spark at the BBC noticed that if the camera is in auto shutter - it is variable - like a clear scan shutter. So, you can fool the camera into giving a clean computer screen - no black or white bars. Here's how...

Frame a shot of the computer screen
Start with the camera set to 0dB gain and auto shutter
Use auto iris to get the correct exposure
Once you are happy with the exposure press the iris button so, the camera is now in manual iris.
VERY SLOWLY tilt the camera up, then down, until you see the flickering on the computer screen disappear.
Once the screen has completely stopped flickering - press the shutter button IMMEDIATELY.
Going into manual shutter mode - holds the correct shutter speed.
Done!

If you have a VX2000 here's a method you can use coutosy of Tom Hardwick member of the VX2K forum

Select AEA (aperture priority auto) via the top button marked 'program'
Now point at the computer screen and of course the sync bars will be there.
Move the camera gently away from the PC screen into a darker surrounding - as you're trying to slow the shutter speed.
When the bars stop rolling you push the 'exposure' button, effectively locking in this shutter speed.

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Move on to...: Part 6: BATTERIES
Or back to...: Part 4: WHITE BALANCE

Christina Fox