What is a Cine Lens?
Simply put, cine lenses or cinema lenses are lenses that are designed specifically for cinematography. Where photography lenses are designed to control focus and aperture for a single picture, a cine lens is designed to have manual control over both focus and aperture in order for filmmakers to change values more easily while shooting video.
There are 3 main distinguishing features cine lenses have compared to conventional photographic lenses
1. "Clickless" or "Declicked" aperture ring.
Some of you familiar with photography lenses may be reading saying "Aperture ring?"
While most modern photography lenses have focus rings, and in the instance of zoom lens, a zoom ring. Older photography lenses and cine lens has an additional ring, an aperture ring that controls the amount of light entering the lens. This is in contrast to modern photography lenses that control aperture electronically. The reason this ring is clickless or declicked is because older photography lenses would lock in aperture for single photos. Photography lenses used for film are often modified to be declicked so that they can achieve a smooth aperture transition.
Why should a cine lens have this? Say you have a shot that starts with a subject in an interior, going out to an exterior. Instead of shooting inside where there's lower light and then cutting to outside because you have to change your settings for the exposure change, you can simply close your aperture in camera for a single shot smooth transition. To make this as smooth as possible, you want your aperture to be measured as accurately as possible, which brings us to T-stop
2. Cine lenses use T-stops over F-stops
“But I only have F-Stop?”
F-Stops are calculated purely by geometry, it is the ratio of the aperture opening to the lens size. lower numbers are a higher ratio giving a theoretical maximum speed for a lens. Hence why people prefer faster lenses which also provide a shallow depth-of-field. However, this does not account for a number of factors that change the way light passes through. The better the glass, the design, the coatings and the construction, the more light actually passes through it.
T-Stops (Transmission Stops) are a much more accurate gauge of how much light is actually transmitted through the lens and arrives at the sensor. Why should a cine lens have this? Most photography lenses can lose ¾ or more of a stop of light, making the F-Stop label misleading in the real world when making focus marks. T-stop accounts for this providing an more accurate measure, which results in more accurate aperture. This can be critical when filming scenes that have various light sources. filmmakers may need to adjust aperture in order to ensure subjects are exposed correctly and consistently during a single shot
3. Similar Form Factor
Cine Lens kits often come in a series of primes, or a pair of zooms, that cover a variety of focal lengths. These series or kits are often built to the same size and specs, in order to maximize interchangeability, lenses within a series of cine lenses are often identical in transmittance of light (maximum T-stop). You'll also notice that cine lenses have gear like rings for focus pulling.
Why should a cine lens have this? Besides the visual aesthetic, lenses with a similar form factor save time during filming. Camera rigs and kits take time to set up depending on location and movement in a scene. When a lens change happens, lenses with similar form factors and attributes can be swapped out quickly.
Can you find photography lenses that can do the same things that cine lenses can? Yes.
Faster apertures, declicked older lenses, and third party gears are all methods and tools to close that gap and save a few bucks on expensive glass. All that said, I would love a good parafocal lens, but I’ll save that for a future blog.
Watch the latest Vlog below to see what my favorite lens right now is.
