Our team was recently hired to shoot a video for a country that uses the PAL encoding system. The project is set to be shot and edited in Canada and then sent overseas. The shooting specs for this project require 1080i50 in a .mov wrapper. To achieve this, we need to switch our camera’s mode from NTSC (60Hz) to PAL (50Hz). However, it’s not that simple. We need to understand why NTSC and PAL standards exist and how they affect video.
The United Kingdom, Africa, Australia, most of Asia, and Russia have an AC frequency of 50Hz, while North America and some other countries have 60Hz. This divide is due to historical economic factors. Manufacturers in America focused on producing 60Hz equipment, while those in the UK focused on producing 50Hz equipment, establishing their own monopolies.
50Hz and 60Hz are not arbitrary frequencies. They were chosen for specific reasons. For instance, certain lights tend to flicker when a low frequency current runs through them. If the frequency is sped up to 50Hz, the flickering goes unnoticed by the human eye, contributing to the popularity of 50Hz.
However, the camera’s eye (its sensor) can still see this flicker, in footage shot in PAL, 1080i50, 1/50 shutter speed, under 60Hz fluorescent lighting. Although our camera sees a clean, flicker-free image, the camera recorded a grainy, flickering effect over a curtain in the background.
To prevent flicker in your video, you need to synchronize your camera to the electrical frequency of the lighting. You can either change your camera’s frequency setting to match the electrical frequency of your environment or sync your shutter speed to the electrical frequency. We’ve provided tables with commonly used frame rates and corresponding safe shutter speeds/angles for shooting under 50Hz or 60Hz lighting.
In conclusion, understanding the difference between NTSC and PAL standards and the effect of household electrical frequency on video is essential in producing high-quality footage.
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