What is the difference between a cine lens and a regular still camera lens?

[jamescooper18]

What is the difference between a cine lens for a 35mm camera and a regular still camera lens? Can anyone give any details on this?

 

[Destin]

What is the difference between a cine lens for a 35mm camera and a regular still camera lens? Can anyone give any details on this?

Generally the cine lenses have focus ring gears on them. Other than that, I'm also not entirely sure.

Following for answers from more informed members.

 

[480sparky41 40]

Cine lenses are also 'de-clicked', meaning the mechanical detents at major f-stops on the aperture ring have those detents removed so the aperture ring moves smoothly. This is so the aperture ring can be adjusted while recording without having those click-stops cause camera movement as well as abrupt changes in exposure.

 

[table1349]

Difference? About 1/3 more expensive.

 

[fmw]

Also they are likely to be manual lenses on your camera.

 

[FotosbyMike]

Also cinema lens have a true f-stop reading meaning, say a lens is F-2.8 that is a really good estimate but not exact it can be more like F-2.9 or f- 3.0. Good cinema lens have T-stops ratings like the Canon Cinema Prime CN-E24mm T1.5 L F Lens.

 

[chuasam]

Zoom Cinema lenses are also parfocal.

 

[Bill The Lurker]

there's a whole pile of differences, geez.

the focal length doesn't change when you change focus distance (no focus breathing)
the focus distance doesn't change when you change the aperture
the focus distance doesn't change when you zoom (that's what parfocal mean)
the rings are all clickless, as noted
some of them may have points to attach various accessories to make focus pulling easier

basically you can change any aspect of the lens' configuration without messing up any of the others, and nothing makes any noise when you change it, and it's easier to change stuff

this all impacts both mechanical and optical design in expensive ways, which is why they cost more. often much much more than "1/3 more".

 

[Solarflare]

What is the difference between a cine lens for a 35mm camera and a regular still camera lens? Can anyone give any details on this?

- No errors that are perfectly OK on a still lens but would disrupt a video recording. This means changing one parameter may not change another. The main examples are: changing the aperture changes the focus, changing the focus changes the focal length, and for zooms changing the focal length changes the focus. This MASSIVELY complicates lens design compared to still lenses.

- T-stop instead of f-stop. Cine lenses need to have exact same transmission, the depth of field question is a perfectly secondary question. Thus they use T-stop (T for transmission) instead of f-stop. As mentioned in the video, the T-stop is also constant over the range for zoom lenses.

- Manual focus. Only manual focus is truely reliable focus. If you spend thousands, tens of thousands, hundreds of thousands or even millions on the actors, you cannot have unreliable focus. Thats also why there are always two people operating the camera - one exclusively manages perfect focus.

- Constant size. Cine lenses will often have the exact same external size in order to be able to quickly swap lenses.

- Geared. Cine lenses might be geared in order to drive them more comfortably, precisely or even electronically (as mentioned in the video, for example for smooth zooming).

 

[The_Traveler]

is cine focus by distance on a scale or by eye?

 

[Dave442]

is cine focus by distance on a scale or by eye?

Usually both, however the focus puller is not the one looking through the camera for most cinematic productions. And distances are usually those established beforehand so the focus puller knows where to set the focus of the lens during the scene.

 

[The_Traveler]

is cine focus by distance on a scale or by eye?

Usually both, however the focus puller is not the one looking through the camera for most cinematic productions. And distances are usually those established beforehand so the focus puller knows where to set the focus of the lens during the scene.

How is focus maintained when zooming or when the subject is moving?

 

[chuasam]

is cine focus by distance on a scale or by eye?

Usually both, however the focus puller is not the one looking through the camera for most cinematic productions. And distances are usually those established beforehand so the focus puller knows where to set the focus of the lens during the scene.

How is focus maintained when zooming or when the subject is moving?

The distance to the camera does not change.

 

[Piotr FOX Wysocki]

distance ring on cine lens has way more travel, than regular lens. so you can precisely set the distance.
good focus puller can set focus just looking at the distance between camera and actor, and this distance can change constantly and he still will be able to keep everything sharp.
but this is a topic for a book

cine lenses could have quite few gadgets, like:
continuous remote readout of the precise focus setting, T stop and depth-of-field from electronics inside the lens
record lens settings accurately, frame-by-frame,
standardized size of the lenses so for example lenses from 18mm to 135mm are the same size,
so when you change from 32mm to 75mm you don't have to re-rig whole follow focus system and matte box etc.

 

[jamescooper18]

Difference? About 1/3 more expensive.

Its undoubtedly an important information for me!