p.1 #1 · Cine lens vs photo lens. Can someone educate me?
I've been looking mainly at the rokinon/samyang line of lenses for video and I see that they offer cine lens versions of their popular photo lenses. Other than price, is there any advantage to buying the photo lenses over the cine lens? As I understand it, their cine lenses have the same optical construction and quality. Also their aperture rings are click less making them smoother in operation. Is there anything else I have missed? Is there any other reason to buy the photo lens other than price?
p.1 #3 · Cine lens vs photo lens. Can someone educate me?
Not a video person, but I can think of two characteristics of a video lens that are different than a photo lens.
1) When you change focus on a photo lens, it may change the effective focal length of the lens slightly. This doesn't effect photos much as you take one instant in time with the focus fixed. In a movie, it is highly distracting to have the periphery of the shot move as the focus follows a subject in frame, or switches from one subject to another. Good cine lenses minimize this effect.
2) A cine lens aperture is rated in transmission stops (T-stops) This is like a f-stop, but takes into consideration how much of the light actually makes it through the lens. Better lenses (better optical coatings on the elements) transmit more light. Rating lenses this way allows a director to swap between types (or brands, or quality) of lenses and set the lens to allow the same amount of light through. When shooting on film, and having multiple camera vantage points, this allows cutting between views without the light level changing in the finished product.
I don't know a thing about the lenses you are considering, so perhaps someone with experience with them can chime in.
p.1 #5 · Cine lens vs photo lens. Can someone educate me?
Those samyang lenses are just re-bodies stills lenses with de-clicked aperture (for smooth iris up or down during recording), focus gears built in and smooth focus throw. They would potentially be worth it if you intend to use a follow focus or want better build.
They are not purpose-designed PL mount hand made cine lenses in the tradional sense (with prices ranging from $5k-$30k per lens). Lenses like the Cooke S4 primes are in another category all together. Those are really rental items.
p.1 #6 · Cine lens vs photo lens. Can someone educate me?
A good cine lens will have a long "focus throw". That means that the focus ring (for manual focus) has to be turned much farther around the lens for the same amount of focus change. That way you can get smoother focus pulling and smoother follow focus.
This is in addition to points mentioned by other posters.
p.1 #7 · Cine lens vs photo lens. Can someone educate me?
Basically, a cine lens is made for video production.
They have measured T/stops. Not sure what the T stands for, but it's an actually measured amount of light, not just a mathematical formula describing how big the iris is.
The focus ring will generally have a larger play for you to get perfect focus.
And lastly (as I am aware), the aperture control is ALWAYS manual, and smooth. No clicks.
p.1 #9 · Cine lens vs photo lens. Can someone educate me?
JesseShotland wrote:
They have measured T/stops. Not sure what the T stands for, but it's an actually measured amount of light, not just a mathematical formula describing how big the iris is.
T = Transmission
That way shots can be matched from shot to shot within a scene even if they were shot with different lenses.
It was critically important in the days of film, less so today with digital post-production but even now it saves time and fuss.
