ACADEMY
ULTIMATE GUIDE TO LENSES
CINE ZOOMS
If you want all the handling advantages of a cine prime such as T-stops, long-throw focusing rings and de-clicked iris rings, but don’t want to carry a bagful of lenses around, the latest cine zooms might be just what your filmmaking needs. But there are some disadvantages – the lenses are larger and more pricey than a single cine prime, for example. They also require larger rigs as there is an additional control needed for the zoom ring. Optical quality is slightly compromised as the lens has to perform at various focal length settings, and the maximum aperture is far less than a prime, so super-shallow depth-of-field is far less easy to attain. Of course, they do offer the advantages of more precise framing, no time wasted changing lenses between shots, and are significantly less expensive than a full set of primes. Compared to DSLR-type zoom lenses, cine zooms are designed to minimise focus
“Compared to DSLR-type zooms, cine zooms minimise focus breathing and zoomshift”
breathing and zoom shift. When zooming a conventional DSLR lens, the focal point shifts so you have to refocus, and often the image skews slightly off centre. This makes reframing slower, and zooming during shooting impossible. Cine zooms are built to minimise focus shifts and off-axis changes by driving the front focus group and the zoom group independently, either optically or mechanically. Thanks to this, there is no lag of the type you’ll often find with fly- by-wire lenses. Most cine zooms have a large, 200° focus rotation angle, more than double most DSLR lenses; three mechanical lens rings control the focus, zoom and iris. The iris ring is stepless for greater precision when changing exposure, and as it’s clickless, there is no vibration or noise as you alter settings. Standard cine lenses like follow focus rigs all fit easily due to the 0.8M standard-sized gear pitch on the focus, zoom and iris rings. At the top end of the cine zoommarket is the Zeiss LWZ, which stands for Light Weight Zoom. It’s for Super35 sensors, has a 21-100mm range, weighs 2kg/4.4lb and costs £8484/$10,400 – so it’s not really light or cheap. However, it is around half
the price of Zeiss’ premium cine zooms. It uses all of the legendary Zeiss know-how and build quality, just in a lighter package. At far more affordable price points are zooms from Sigma and Fujifilm. Sigma has the High Speed Zoom Line to cover the Super35 frames and the full-frame FF Zoom Line, which has a £4800/$4999 24-35mm T2.2 in EF and E mounts. The Super35 High Speed Zoom Line comprises an 18-35mm T2 and a 50-100mm T2 at £3899/$3999 each. The Sigma bodies are all metal construction, with standard 0.8M ring gearing, and are splash and dust resistant – including a weather seal on the EF lens mount. The body is reasonably compact, given the speed of the lens. Colour balance has been standardised across the range of lenses, as has the 95mm front diameter and the 82mm filter size, plus the ring gear positions. The focus ring has 180° of travel, the zoom 320°, and the iris has a constant angle between stops. On some versions, the aperture setting is fed to the mount so on suitably equipped cameras you can see the value set in the viewfinder, and it will be recorded, along with zoom and focus information, in metadata.
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PRO MOVIEMAKER SPRING 2020
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