What exactly is Rec. 709?
One of the problems facing camera people is the huge number of ways in which pictures are provided, with every manufacturer developing its own cleverly-named approach to encoding colour and brightness. Beneath all this, acting to some extent as a lowest common denominator is the Independent Telecommunication Union’s Recommendation BT.709, which is commonly referred to in-camera configuration menus and casually thrown around in technical writing, as if its absolute characteristics were a matter of sheer instinct to most people. Its absolute characteristics, though, aren’t widely discussed in everyday language. It’s not that hard to find claims that Rec. 709 provides no more than five stops of dynamic range, but that’s a bit of a leap, as we’ll discover here.