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Sony a7S Full-Frame Mirrorless Camera, Part 3: Video Camera Review

In the last two articles in this 3-part series on the Sony a7S, we covered a lot of ground discussing what to look for in video lenses and lens adapters for the Sony e-mount that is native to the Sony a7S. Now it is time to take a deeper look at the Sony a7S as a video camera, with comparisons to the Canon 5D MKIII and Panasonic DMC-GH4.

Clean Image Zoom

The sensor zoom is is one feature I wish I had on my FS700 and is borrowed from the Sony NEX-EA50 video camera that unfortunately was built around a photo sensor. In practical use, I find that working with 3x zoom DSLR lenses can be very limiting and I have previously written about this challenge and the EA50 here. Often, 3x zoom is sufficient, but because frequently I can't control my position relative to my subject, I find myself wanting a lens in a different focal range. Sometimes this is just a matter of switching between my 16-50mm f/2.8 lens and 28-75mm f/2.8 lens, but at other times I want the range to be 50-150mm. While such a lens does exist in Sigma’s lineup, it isn’t a parfocal lens. You can read the previous articles in this series (see related article links below) for more detail on parfocal and non-parfocal lenses.

It used to be that a full-frame camera was useful when you wanted to shoot extra wide but was useless when you needed additional focal length range, assuming you have the same lenses to choose from. This is no longer the case with the full-frame Sony α7S because you can get the best of both worlds: full-frame wide, APS-C or Super35mm crop sensor telephoto, and now an additional 2x clear image zoom.

New E-mount Lenses

Sony’s new 18-105mm f/4 power zoom E-mount lens and soon to be released 28-135 f/4 power zoom full frame E-mount lens will do nicely to cover a wider focal length range in a single parfocal lens, but imagine the versatility when you combine a 2x sensor zoom with the ability to change between APS-C mode (which should be called S35mm mode for video) and Full Frame mode. Whereas 3x zoom used to be the best you could do if you wanted a true parfocal DSLR lens, when you combine APS-C mode and 2x sensor zoom on the new 4.8x Sony 28-135mm f/4 lens, you get an unprecedented 14.4x zoom range. Otherwise stated, the Sony 28-135mm f/4 FE lens on the α7S can cover a 28-405mm range at f/4. That is ENG zoom lens range territory and not full-frame range territory. The best part about this pairing is that you can cover this entire range without the use of teleconverters or lens adapters.

During my review I took photos of the moon on different days in different modes. On the left I shot in full frame with a 600m focal length and on the right I shot in APS-C mode and 2x clean image zoom for an equivalent focal length of 1,800mm. Vivitar 120-600mm f/5.6-8 lens. Click the image to see it at full size.

Less is More

I know that as my lens collection grows I grow increasingly concerned about the safety of carrying so many valuable lenses with me that I inevitably leave somewhat unattended as I film. There will always be a use for specialty lenses and the desire and reason to shoot with multiple lenses, but for me, one of my FS700 kits consists of four zoom lenses, two prime lenses, two lens mount adapters, and two teleconverters, and this full kit is getting out of hand.

I look forward to reducing my kit to a much more manageable 28-135mm f/4 zoom lens, two prime lenses for when I want a razor-thin depth of field, and one small wide-angle zoom lens like the Sony 11-18mm f/4 E-mount lens. All would be native E-mount lenses so I can sell the adapters and teleconverters to another shooter who hasn’t yet figured out this more efficient lens workflow.

The full-frame Sony α7S, when paired with a fast prime lens, can achieve a razor thin depth of field and out of focus bokeh look. Minolta Rokkor-X 50mm f/1.4 lens. Click the image to see it at full size.

As a video camera, the α7S isn’t perfect, and despite its impressive 14.4x zoom range potential when paired with a single lens, it leaves room for Sony to release a camera around the same sensor on a more traditional large-sensor video camera body. (That is, if I'm allowed to say "traditional" and "large-sensor form factor" in the same sentence, as this whole form factor is so new, and arguably there are more misses than hits when it comes to the actual form factor, which includes ergonomics, LCD and/or viewfinder placement/articulation, and ability to be both handheld and shouldermounted.)

Some easy fixes that Sony can implement to improve the intuitiveness of the camera as a video camera would be to allow the user to assign the video record button to the shutter button when the mode dial is turned to video mode and to extend the lower range of the zebras so you can meter proper exposure when paired with SLOG2. Personally, I'm waiting for Atomos to release the Shogun 4K recorder and monitor with built-in look up tables (LUTs) before I begin to test and shoot in either 4K or SLOG2 on the α7S.

Related Articles
People are buzzing about the Sony a7S, so Streaming Media Producer is launching a comprehensive three-part review. In this first part, we'll examine lens options for the Sony a7S and related cameras, as well as what to look for in a video lens.
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