Development of cine lenses on the market

In 2014 Samyang began producing lenses for use in the video field. Still on the market, these lenses are distinguished from purely photographic optics by the presence of a toothing for the follow focus both on the focus ring and on that of the diaphragms and for a ring of diaphragms that flows smoothly. The Korean company initially identified this line of lenses with the acronym VDSLR, underlining its vocation for use on digital SLRs capable of making videos. For marketing reasons, he then began to advertise these lenses as Cine Lenses , but distinguished them from the film lenses of the Xeen line, also of his own production, defined at that point.Professional Cine Lenses. This is how some confusion began to spread about what a Cine lens actually is.

Toothed rings, fluid and with hard stop

All the rings of the cine lenses have a standard 0.8mm toothing intended for coupling with the follow focus, a tool that can therefore be used to manage not only the focus but also the apertures and any zoom.

The aperture ring rotates smoothly so that you can set any aperture and change it without interruption during shooting.

The rotation of the focus ring locks at both ends of its excursion, so as to allow automatic calibration of the electronic follow focuses and favor the reliability of the markings on the mechanical follow focuses.

Wide range of fire and reliable and numerous distance indications

The focus ring of the cine optics is able to rotate at least 270 ° and the excursion is well distributed over the entire stroke, so as to allow adequate management of the focus both in terms of precision and speed.

Distance indications are factory calibrated to be reliable.

To allow the user to correct any discrepancies between the indications on the focus ring and the effective focus distance, cinema lenses are usually equipped with a shim set , a series of discs that can be positioned between the barrel and the bayonet in order to alter the draft of the system in use.

The distance indications on the cine lenses are much more numerous than on the photographic lenses, so as to provide the focus puller with more references to pull the focus, perhaps using ultrasonic meters.

In cine lenses, distance indications are often found on both sides of the barrel, so that the focus puller can read them regardless of whether it is to the right or left of the operator.

Possibility of shimming

Shims are thin washers fractions of a millimeter. Interposed between the barrel and the bayonet of an objective, they are used to alter the draft of the system in use, so as to make the distance indications present on the focus ring reliable if inaccuracies are noted. Each cinematic lens is designed to accommodate one or more shims dedicated to it. Some optics are sold together with an entire shim kit that can be easily used by an average user. To apply shims on more complex optics, instead, advanced skills are required and usually the intervention of specialized assistance is used.

There are also cine cameras that allow shimming behind the bayonet of the camera itself, using the shim kits sold as accessories by the manufacturers.

In the photographic field, the practice of shimming has only appeared in recent years thanks to the spread of adapter rings and modification kits. These tools, in very rare cases, are now sold together with a shim kit, mostly for the purpose of ensuring the user focus at infinity.

Indication of the actual brightness

In cine lenses, apertures are referred to as the T-value, a measure that takes into account the light absorption of the optical design. In this way you can be sure that always working at the same aperture, the exposure remains constant even when changing lenses.

Play-free mechanics and stricter quality controls

The mechanical quality of the film lenses must guarantee the absence of play and the repeatability of the results. If the focus ring were not precise and brought over a certain distance to focus sometimes a little further and sometimes a little further back, the markings on the follow focus would be unreliable. If there was a perceptible play between the helicoids, the frame would move visibly at each change of focus. In essence, cine lenses must offer the best in terms of build quality; any mechanical defect, in the cinematographic field, is evident. This is another reason why quality controls on cinematographic lenses are carried out on each individual specimen rather than on a sample basis, a factor that significantly affects the price of these tools.

Color rendering, aperture shape and maximum brightness uniform in each line

In photographic kits it is normal that lenses from different generations coexist and that they do not share the same anti-reflective treatment or the design of the diaphragm or the same type of glass. Such inhomogeneity is unacceptable in a cinematographic set, which must instead ensure the maximum uniformity of rendering between all the lenses that compose it so that the visual continuity of the filmic work is facilitated. Each cine lens therefore belongs to a specific line and when shooting a film it is normal that only lenses of a certain line are used.

In a film kit, even the maximum brightness is kept constant between the various models. The extreme focal lengths can be an exception, which in order not to deviate excessively in terms of price and size from the other lenses of the same line can have a more limited maximum aperture.

Dimensions and positioning of the ferrules uniform in each line.

Within a cine kit, all the barrels have the same dimensions in terms of length, width and front diameter and have toothed rings always placed at the same distance from the bayonet. This constructive typing allows you to change lenses without having to change the rig of the camera. The extreme focal lengths can be an exception but as a rule, within each kit, the physical dimensions and morphology of lenses with focal lengths between 20 and 90mm are identical.

Focus breathing and parfocality under control

In the design of cine lenses, the focus is on minimizing focus breathing, which is the fact that a lens changes its focal length based on the distance of focus. In practice, when the focus breathing is high, the focus changes are associated with a noticeable zoom effect.

In the case of zoom lenses, cine optics are always expected to have good parfocality, i.e. the ability to keep the focus distance more or less constant during zoom movements.

Focus breathing and parfocality are two parameters usually neglected in the design of photographic optics.

The original film optics and the rehoused

Cine lenses can be divided into two large groups: original and rehoused lenses. While the original lenses are designed for cinematic use right from the design stage, the rehoused lenses reproduce a photographic optical scheme inside a film barrel.

Taking advantage of pre-existing and already commercialized optical designs, rehoused lenses are decidedly cheaper than the original film models but are still sold at a price many times higher than that of the photographic counterparts. For example, the popular € 700 Sigma 18-35 / 1.8 becomes the € 4,500 Sigma Cine 18-35 T2. The enormous price disparity is linked not only to the best mechanical quality and the much smaller user base, but also to the theoretically much stricter quality controls.

The figures go up even further when original cinema optics are taken into consideration. The price of a Zeiss Master Prime, depending on the model, varies between €30,000 and €50,000; the entire Leica Summilux-C kit, consisting of 12 lenses, is sold for €400,000; the ARRI Anamorphic 19-36mm T4.2 alone sails around € 90,000. Clearly these goals are being sold to services, not end users.

The situation described so far changed in 2016 with the entry on the market of Xeen lenses, the first cinematic rehoused lenses marketed at relatively cheap prices. Since then, other brands and kits with similar characteristics have appeared on the market (DZOFilm, Meike, Irix…) mostly from China or Korea; in practice, a race to the bottom of prices has begun by these companies of the Rising Sun which has meant that today it is possible to buy a film lens, even if it is low-end, within € 1000.