DPP Solutions: The Lingo

Canon CN-E14mm T3.1 L F

For Canon, Micro Four Thirds, Nikon and Sony mounts, Rokinon has been producing a number of very affordable cinema lens alternatives to lenses produced by the major manufacturers. Several are available as bargain-priced collections of essential primes on Amazon, like the Rokinon Full Cine Lens Kit with 85mm, 35mm, 24mm, 14mm and 8mm lenses, or the Super Fast T1.5 Cine Lens Kit with 35mm, 24mm and 8mm focal lengths.

Lux

In still photography, we don’t use the term lux that often. It’s a measure of illumination. We tend to use EV (Exposure Value) or lumens more than we use lux, but it’s frequently used in filmmaking. It’s a measure of light over a given area. As a unit, lux is equal to one lumen per square meter.

Shutter Angles

With film-based motion cameras, the shutter is a rotating semicircular disc. As it spins, the film is exposed as it passes through the camera gate. This also determines the shutter speed. By adjusting the shape of the semicircle, the effective shutter speed changes. That’s the shutter angle.

With digital cameras, the shutter works differently, but you’ll still hear motion people discussing shutter angles. It’s the key adjustment for controlling blur in the footage. In motion capture, some blur is frequently desired because it gives the footage a smooth and more pleasing look.

T-Stops

You’re intimately familiar with an ƒ-stop, and a T-stop is pretty much the same thing. T-stops are more common in motion capture, and are particularly familiar to filmmakers who have used film cameras. T-stops are more accurate than ƒ-stops for determining exposure because T-stops are ƒ-stops that are adjusted to account for light-transmission efficiency. In an optical system, the components hinder the amount of light passing through by a slight amount. For motion capture, where consistency between lenses from shot to shot is critical, T-stops are preferred. That doesn’t mean you can only use lenses with T-stops, of course, but be aware that when you’re shooting motion and you change lenses, even if you set the same ƒ-stop, the exposure likely will shift slightly.

These are a few of the particular differences between still photography and motion terminology. There are plenty of other semantic obstacles between the two worlds, but at the end of the day, the motion and still worlds are more similar than you may think.

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