Sony Breaks New Focal Length Ground in Professional Video--and No One Notices

On February 3, 2016, Sony announced a new camera, three new lenses, and two teleconverters. The media jumped all over the specs on the new Sony a6300 mirrorless camera, and with reason, but they all skipped over the big announcement. For live producers, the big news only partially concerns one of the three new lenses, the 24-70 f/2.8 GM FE, 70-200 f/2.8 GM FE, and 85mm f/1.4 GM FE, that are the initial offerings in Sony’s new line of G Master lenses (Figure 1, below).

Figure 1. The Sony A6300 and new GM FE lenses

For the photographic press, the a6300 and the new faster GM lenses are the main story. But as a professional video producer who has been enjoying the benefits of filming on Sony’s Super35 sensor professional video cameras since Sony introduced the FS100 in 2010, Sony’s new e-mount teleconverters, when paired with Sony’s new FS5 (Figure 2, below), are the big story that isn’t being talked about. This new combination has allowed Sony to break the telephoto barrier that was stuck for the longest time at the equivalent telephoto range of a 10x zoom camcorder. Professional video producers who film wildlife, conferences, and many live events needed more telephoto range, and this is a big reason many have had to maintain professional camcorders alongside their Super35 interchangeable-lens video cameras.

Figure 2. The Sony PXW-FS5

Breaking the 240mm Barrier

When Sony launched the e-mount lens line, the company’s engineers weren't sure how they would design a zoom lens that would have a focal length beyond 200mm and even lenses that were faster than f/4. Last year they broke the 200mm barrier by a paltry 20% with the Sony FE 24-240mm f/3.5-5.6 lens and today they broke the f/4 barrier with a pair of f/2.8 zoom lenses.

Video professionals who use the professional line of Sony video cameras--the FS100, FS700, FS7, and FS5--require lenses with a constant aperture; otherwise the iris closes while you zoom in. Granted, Sony e-mount lenses have a trick up their sleeves that Canon and Nikon SLR lenses do not. Because Sony uses an electronic iris on their e-mount lenses, when zoomed out to the widest focal length, if you first stop-down a variable-aperture lens to at least the smallest aperture in the lens’ variable range (f/5.6 for the above 24-240mm lens), when you zoom in, the lens holds that aperture through the entire zoom range. When using this technique, the variable-aperture 24-240mm f/3.5-5.6 lens can act like a constant-aperture 24-240mm f/5.6 lens.

I know, 20% extra telephoto zoom range with a loss of an entire stop of light sensitivity isn’t that exciting. But stick with me, because at this same f/5.6 level of light transmission, Sony just demolished their new 240mm barrier to an incredible 1200mm, enabling true long-lens work on Sony Super35 video cameras for the first time. This also means that in some cases, video producers can finally ditch their traditional small-sensor camcorders with fixed lenses.

Focal Length Explained

Even the Sony professional camcorder with the most modest camcorder zoom lens, the 1" sensor Sony X70 (Figure 3, below), has a 12x zoom. This translates into a longest full-frame equivalent (FFE) focal length of 348mm. By comparison, a 200mm lens on a Super35 sensor camera, which has a 1.5x crop factor, maxes-out at 300mm (FFE), which is what a 10x camcorder would typically deliver, and that just isn’t enough on the telephoto end. Every camcorder has a slightly different FFE at its widest zoom but the ones I will discuss here are between 26-28.8mm.

Figure 3. The Sony PXW-X70

The $2,800 1/3" sensor Sony NX3/1 has a 20x zoom lens that has an FFE of 28.8-576mm, and the Sony X160 ($3,749) and X180 ($3,995) both have the same 1/3” sensors and a FFE of 26-650mm on their 25x lenses. I contend that for most work, a 25x zoom range provides enough zoom to film a presenter from the back of even the largest of conference rooms. But if you already own (or desire to own) a large-sensor video camera like the Sony FS5, because of the creative opportunities it affords with a wider exposure latitude thanks to SLOG3 and a shallow depth of field thanks to its larger Super35 sensor, then you’ll be excited to hear that now you can have your zoom and keep your large sensor too.