Using a larger, more expensive cinema style lens on your camera when you're filming will do more than just get you a ton of likes on your behind the scenes Instagram photos.
There are a lot of reasons you’d rent or buy a cinema lens instead of filming videos with a still photography lens.
Let's discuss the main differences.
The first thing you’ll probably notice other than how much larger cinema lenses are is how they’re geared for both pulling focus and changing the aperture. The opening through which light reaches your camera’s sensor, or aperture, on most still lenses can usually only be controlled electronically by the camera you’re using. You change it in increments of one third an f stop at a time. f2.8, 3.2, 3.5, 4.0, and so on.
With a cinema lens you can get more precise, manual changes in aperture and do so smoothly, like when you’re going from a bright outdoor setting to a dim indoor environment. Some still lenses like the Sony G-Masters now allow you to de-click the aperture ring though.
The gears on the side of a cinema lens allow the addition of a follow focus system for you or a 1st A.C. to smoothly change focus or aperture with either a wheel next to the lens or a wireless remote system, which is most helpful when using a gimbal or a drone.
Pulling focus on a cinema versus a still lens is way more precise and smoother too. Some still lenses from Sony or Zeiss use fully electronic “focus by wire” systems, where the faster you move the focus ring, the more it changes focus. A cinema lens on the other hand is completely analog, with markers on the side for the focus distance.
A cinema lens also has a much larger focus “throw”, or how much you have to turn the focus ring to change focus. On a still lens you might only have around a quarter of a turn on the barrel to rack focus. On a cinema lens, you may get two or three hundred degrees of rotation. The focus ring on a cine lens also has built-in hard stops at infinity and the closest distance it can focus. This makes it much easier to get critical focus when preparing a shot, which is getting more and more important when filming in resolutions like 4K, 8K, and beyond.
Another focus related feature of a cinema lens is they typically have less focus “breathing”, or changes in how much is in your angle of view. If you watch the edges of your frame while you change focus on a still lens, you’ll see more or less visible in the frame, which can be quite distracting while racking focus between two objects.
On a cinema lens, you’ll get less or no focus breathing on the edges of your frame when changing focus.
Parfocal Focusing on Zoom Lenses
One more focus related feature is that if you’re using a zoom cinema lens, it will be parfocal, which means as you zoom in and out, the focus distance will stay exactly the same. This isn’t the case with a still lens and you’ll need to re-focus ever so slightly after zooming in or out.
Bokeh Shape & Size
Another feature of cinema lenses is they have more blades on the iris that opens and closes as you change aperture. Inside this Canon Cinema Prime lens is an 11 blade iris, which leads to rounder bokeh in a blurred background and rounder lens flare shapes.
A Canon L-Series lens only has 8 aperture blades, leading to less round, or even octagon shaped bokeh or lens flare.
Similarity of Lens Sets
Another benefit of filming with cinema lenses comes when you’re shooting with multiple lenses. First off, a set of cinema lenses from the same company is created together and the glass is coated to make sure all of them are color matched.
Next, they are usually all the same physical size no matter which focal length you use, which means the gears for changing aperture, zoom, and focus are in the same place. They also have the same sized barrel and threading for add-ons like neutral density or diffusion filters. This makes changing between lenses way easier and faster when using rails, matte boxes and follow focus systems.
T vs F stops
Another major difference between stills and cinema lenses are T and F Stops. Without getting too technical, an F-Stop is the ratio between the diameter of the aperture in the lens (a.k.a. The size of the opening) and the focal length of the lens (like 35, 50, or 85mm). The issue with F-stops on stills lenses is as you change between lenses and different focal lengths, the amount of light let in through the lens changes. Even if you use the same F-stop and camera settings your exposure values will be different on different lenses, ever so slightly.
On the other hand, T-stops used on cinema lenses measure how much light is being “transmitted” (hence the T) to the sensor. This means if you used the same T-Stop on multiple cinema lenses even at different focal lengths, the exposure should match exactly on all the lenses used from the same set.
Lens & Glass Quality
Other considerations and benefits of cinema lenses are usually better controlled chromatic aberration (which is the color fringing you may see on edges during a bright scene), less barrel distortion at wider angles, and more consistent edge to edge sharpness. Cinema lenses are also almost always heavier, which makes run and gun filming or traveling with them a bit more difficult too.
As far as cost, you’re generally going to spend 4 to 5 times as much for a cinema lens from a major manufacturer like Canon or Zeiss as you would on the stills equivalent. The reason for this is not only the better construction and materials, but also the coating and the testing precision in machining and assembly that goes into making sure all the lenses in a set match.
Some of them even use the same exact internal glass you’ll find in their stills lenses, just housed differently. So if you don’t need the benefits we’ve been talking about, you can save some money. Also, you may want to use the lenses for dual purposes of photo and video, so that may influence your decision as well.
There are some companies like Rokinon that make cinema style versions of their lenses that are close in price to their photography counterparts though, just know you won’t get autofocus abilities when using cinema style lenses.
It typically comes down to your project size, its budget, and weight for whether you choose still or cinema style lenses, but now you’re ready to make the right choice when doing so. And once you get into the higher end cinema glass your choosing it for a specific look and feel not just the build.
Be sure to go check out the other video we made on the Lens Pro To Go channel where we compared a $2,000 Camera to a $20,000 Camera too.
And subscribe to the Lens Pro To Go channel for more video and photo gear reviews, comparisons, and tutorials.
Equipment Used To Film This Video
Here is the other video Greg and I filmed together as well.