Good camera lenses don’t come cheap, but if you’re window shopping on Amazon or B&H Photo, you might notice some extreme outliers: cine lenses (or cinema lenses) designed specifically for filmmakers. While you can get a Canon 50mm f/1.8 for $125, the Canon 50mm T/1.3 cine lens is a cool $3,950. So, what sets this cine lens apart? Let’s find out.
Most lens manufactures offer multiple lenses with the same focal length at different price points. To continue the example above, Canon has a 50mm f/1.8 at $125, a 50mm f/1.4 at $329, a 50mm f/1.2 L at $1,299, and the 50mm T1.3 cine lens at $3,950. They all have the same focal length so the image will look similar regardless of which lens you use, especially if you use the same aperture. Still, there are some big difference between them.
One of the biggest differences between cheap photography lenses, expensive photography lenses, and cine lenses is the quality of the materials used. Canon’s 50mm f/1.8—an example that’s popular with amateur videographers—is made from plastic, while the f/1.2 and the T/1.3 cine lens are both made of metal. This means more expensive lenses tend to hold up better in the day-to-day abuse they receive from professionals.
It’s not just on the outside that the materials are higher quality. A lot of work goes into making cine lenses as optically perfect as is humanly possible. While a bit of distortion, chromatic aberration, or vignetting is common in even high end photo lenses, manufacturers go to great lengths to minimize it with their cine lenses. It’s a lot easier to fix a few small problems in post for a photo than it is in a 120 minute feature film.
While the difference in image quality between a photography lens and a cine lens will, in most cases, be too subtle for anyone but experts to notice, it’s experts who are making films.
T-Stops Instead of F-Stops
For photography, aperture is measured in f-stops. It’s purely a measure of the relationship between the size of the lens opening and the focal length of the lens. For videography, however, f-stops aren’t good enough: you also need to know how much light is being lost as it passes through the lens. This is where T-stops or transmission stops come in.
If you have two different lenses—say a 35mm and a 50mm—set to the same f-stop at the same shutter speed and ISO, the resulting image will have a very similar, but not identical exposure. This isn’t really a problem for photography, but it’s a big issue for filmmaking, where you’re often swapping lenses and need everything to remain otherwise identical. To fix it, cine lenses use T-stops.
If you take those same two lenses and set them to the same T-stop, shutter speed, and ISO, the resulting image will be identical. This is why Canon’s 50mm T1.3 cine lens has a series of sister lenses: a 24mm T1.5 and an 85mm T1.3. They’re meant to be used together as a set. T1.5 is identical across all three lenses.
More Precise Focus Control
The vast majority of photos are taken using autofocus. It’s gotten so good in modern cameras that the only time you really need to use manual focus is when you’re doing something super specific like astrophotography. This means that a lot of modern photography lenses have pretty poor manual focus controls. They often don’t have markings for focal distances and, even if they do, they have very limited “focus throw”—how far you can rotate the focus ring before being at the closest focus or infinity—which means you don’t have a lot of control.
Cine lenses are all manual focus and have clearly marked focal distance scales. There are hard stops at the closest focus distance and infinity with a big focus throw in between for super precise adjustments. They also have grooves on the focus ring, which can be used with automated and follow focus devices. This means film makers can quickly switch between two preset focus points or track focus on someone as they move through a scene. If the cine lens is also a zoom lens, then the focus point will remain the same while you zoom—something that isn’t necessarily true of still lenses.
All in all, cine lenses just give you far more control over focus, while photography lenses basically leave it up to your camera.
A Fixed Design
Cine lenses tend to be released in sets like the Canon 24mm, 50mm, and 85mm I’ve been using as an example in this article. All the lenses in the set share the same form factor, filter size, optical design, focus set up, and the like. This means that not only will the image be incredibly consistent between the lenses, but they can also be used with the same accessories. While this might sound like a minor point, it’s actually a huge benefit for filmmakers who are often working with complicated rigs that include follow focus devices, counter balanced gimbals, neutral density filters, and any other bit of kit they can strap on. If you can just swap lenses without having to change anything else, it makes it much easier to focus on the nitty gritty of making your movie.
Cine lenses are incredible pieces of glass, but their specific film making features mean they don’t come cheap. In face, most film makers don’t even own cine lenses (some of which can cost north of $100,000)—they rent them on a day to day basis for shoots. The good news though, is that if you ever want to try one out, you can probably rent it too.