This summer we're re-running some of our most popular articles - just in case you didn't see them first time. Here's Phil Rhode's look at how to understand Waveform and Vector displays
If the recent review of Blackmagic's SmartScope Duo is anything to go by, there's a significant amount of interest in test and measurement equipment. Gone are the days when a light meter and a trained eye was enough; to do better, we need technological measures – test and measurement equipment, and in this article I'm going to discuss a few of the most common approaches and why some may be more useful than others, depending on the circumstances.
Traditionally, digital stills cameras provide a Histogram display which indicates what proportion of the image is at various levels of brightness. While useful, a histogram is a very different – and arguably less comprehensive – way of analysing an image than the more traditional Waveform Monitor, which has its roots as a piece of test equipment used in video facilities and television studios. It provides not only a guide to brightness, but also information on the position of the subject which is at that brightness, as well as other features. Finally, the Vectorscope is a colour analysis tool which was originally intended to allow engineers to fine-tune the performance of analogue tape decks with reference to colour bars, but which may still find application both on set and in the grading suite as a means of assessing whether colours are oversaturated or poorly matched from shot to shot.
We'll use this image of a city street at night (from our NEX-EA50 review) as an example, as it has high contrast and saturated colours: