Choosing The Right Shutter Speed

How does shutter speed affect filming and where do these rules come from? The first rule we learn to start using our HD-DSLR cameras for video is double frame rate is the "normal" shutter speed. This comes from the film days of filmmaking when the camera shutters we half round and would expose half the frame at a time. We are using DSLR cameras that have a version of a focal plane shutter and to get the movement right during filming manufacturers have stuck to the basics that most fiilmmakers are familiar with, so in NTSC land we go at 30 frames per second so "normal" shutter speed is 1/60th second and at this rate (1/50th in PAL countries), everything is just fine.

So why do we want a different shutter speed, well the first idea is low light, you can drop your shutter speed one full stop from 1/60th to 1/30 and not really see a difference in image quality for filming average speed objects. The advantage to this speed is that we do not need to add ISO, or for camcorder speak ISO = gain, this low ISO keeps our image cleaner and crisper.

Next is fluorescent lights, LED lights or T.V. screens, these light sources have a frequency and either pulse or scroll, the job of your shutter speed is to synch with their frequency to remove the pulse. To add to complications, lights in different countries have a couple of frequencies depending where in the world you are. The frequency of lights will be affected by the power supply, so either 50Hz or 60 hertz (not the car rental company),  Here is a link to a directory of countries handy if you are traveling. These numbers look a lot like shutter speeds, so that is the point adjust your shutter speed to reduce the flicker or pulse. With the HD-DSLR you might have to go into the menu and turn your camera from NTSC to PAL or Vice-versa  to get a 1/50th or 1/60th shutter speed.

With DSLR video cameras we are stopped at 1/30th or 1/25th as the lowest shutter speeds, so we can go higher instead and why would we? Well have you seen those cool helicopter shots where the copter is flying yet you can see the individual rotor blades turning, not just a blurry circle. To get that turn your shutter speed to 1/1000 to 1/2000 and check on your cameras LCD display and see if you have frozen or synched the blades of the rotor or aircraft propeller. The other effect you will see is the jello effect as the blades will be curved as they are turning very fast. This technique is good for any fast moving object, think Hummingbirds etc.

So feel free to experiment and give some of your video clips a different look.