Sigma has announced that it will showcase the prototype of a new cine zoom lens at IBC 2024. Unusually for a cinema lens, it will also feature autofocus.
Proof of concept
In a press release published yesterday, Sigma confirmed it will be exhibiting at IBC 2024. IBC 2024 is a professional imaging equipment exhibition in Amsterdam, the Netherlands. This show runs from the 13th to the 16th of September 2024. The press release also announced that Sigma will showcase a new proof-of-concept autofocus cinema lens. It will be based on Sigma’s popular 28-45mm F1.8 DG DN | Art lens. This was the world’s first full-frame zoom lens with a constant maximum aperture of F1.8.
T-stops
Sigma said that the new lens will be a prototype 28-45mm T2 Cine zoom lens. Cinema lenses use T-stops rather than F-stops to indicate the aperture on a lens. F-stops are a ratio calculated from the focal length of the lens and the diameter of aperture. However, T-stops are a measure of the actual amount of light passing through a lens. T-stops tend to be a little lower than F-stops due to the light losses which occur because lenses cannot transmit light with 100% efficiency.
Autofocus
The new 28-45mm cine lens will be Sigma’s first-ever cinema lens with autofocus. Cinema lenses are normally manual only, designed to be controlled by a follow focus mechanism. On larger productions, a dedicated focus puller will be responsible for focus, separate from the camera operator. However, on smaller film shoots, where the camera operator also has to focus, an auto option could be useful at times.
Other features
Sigma has revealed that the new lens will have a focus ring with a distance indicator. Cinema lenses usually have a much longer focus throw than autofocus lenses. This delivers finer control for manual focus. In addition, the shorter focus throw on an autofocus lens means that the mechanism can respond more quickly. The new cine lens will also have a click-free aperture ring. This is important to ensure that exposure can be adjusted smoothly while filming. Sigma also said that the new lens will be compatible with 95 mm matte boxes.
What we think
Sigma’s 28-45 mm Art lens was the world’s first F1.8 full-frame mirrorless zoom. The company also claims it delivers sharpness and clarity comparable to that of a prime lens. Therefore, a lot of film makers will be happy to see that Sigma is working on a cinema version of the lens. It’s also interesting that the prototype will retain the option for autofocus. Even if the performance is slower than the regular version of the lens due to the longer focus throw, it will still be a useful feature for solo shooters.
