New Sony Alpha A7S Full-Frame Mirrorless Camera With 4K Video & Sensitivity To ISO 409,600

Posted by on April 9, 2014

Sony Alpha A7S With 12-MP Full-Frame Sensor

This week at the annual NAB (National Association of Broadcasters) tradeshow in Las Vegas, Sony unveiled a new full-frame mirrorless interchangeable lens camera capable of capturing 4k video and able to shoot at sensitivity levels up to ISO 409,600. The new Sony Alpha A7S is based on the groundbreaking Alpha A7 and A7R, introduced last fall, the smallest full-frame cameras currently on the market. What makes the A7S different from its predecessors is a new 12.2-megapixel full-frame sensor, 4k video, and a host of other features targeted at the professional video market.

I was lucky enough to be invited to Sony’s Alpha A7 press launch in Nashville, last October. During those three days I got a good feel for both the 24-megapixel A7, and the 36-megapixel A7R full-frame mirrorless cameras (read my A7 review and A7R review). I was really skeptical when they were first announced because I believed the larger sensors would defeat the purpose of the mirrorless platform. For me, mirrorless cameras are about compact, convenient portability. However, I was surprised to discover that the A7 cameras really did put full-frame image quality in a very compact package. And I left Nashville convinced I would buy an A7 (or something comparable) in the next year.

Sony Alpha A7S Main Features & Specs:

  • 12.2-megapixel full-frame Exmor CMOS sensor
  • BIONZ X image processing
  • Sensitivity: ISO 100 to 102,400 (expanded: ISO 50 to 409,600 / ISO 200 to 409,600 for video)
  • 4k 30p/24p video output
  • Full HD video at 60p (50p), 60i (50i), 30p (25p); and 720p at 120 FPS
  • XAVC S professional video format
  • Built-in Wi-Fi with NFC
  • Electronic viewfinder
  • 3-inch tilting LCD display

Sony Alpha A7S With 35mm f/2.8 Zess Lens

Enter the new Sony Alpha A7S. Built on the same platform as Sony’s previous A7 cameras, it has an excellent electronic viewfinder, tilting LCD display, built-in Wi-Fi, and it’s way easier to carry around than any full-frame DSLR. Because of the relatively large pixels on the 12-megapixel full-frame sensor, the A7S will have far better low-light performance than the A7 or A7R – both of which are totally useable up to ISO 6400. The native sensitivity of ISO 102,400 (two stops higher than the A7 and A7R) should be a world of difference for low light photography. Expanded, the A7S goes all the way up to ISO 409,600. That’s the same as Nikon’s new D4S professional digital SLR, although the A7S is expected to be even better because of its larger pixels. There’s also talk of improved dynamic range, although information on that front is vague right now.

The A7S does not get the impressive hybrid auto focus system from Sony’s A7, which combines contrast detect AF with phase detect pixels embedded in the sensor. Instead, it uses the same Fast Intelligent AF contrast detect system as the A7R. The A7R’s auto focus is quite good, although definitely not as good as the A7 – especially not for moving subjects. Because the A7S pixels are so much larger, the auto focus performance should be better than the A7R; and the A7S will deliver the best low-light auto focus on the market – useable down to -4EV with an f/2.0 lens.

Sony Alpha A7S With Pro Vide Rig

With 4k video and an NAB tradeshow launch, it’s clear Sony had the video market in mind when they designed the A7S. Besides being able to capture 4k video (30p/24p), it also records full HD video in either AVCHD or Sony’s XAVC S professional format; and in “Super 35mm-equivalent” mode (APS-C crop) it can capture 720p video at 120 frames per second. Just to be clear – the A7S can’t actually record 4k video to a memory card – it doesn’t have the processing power for that. Rather, it streams uncompressed 4k video from the camera to an external recording device via the HDMI connector.

Other notable video features on the new Sony A7S are a special S-Log2 tone curve for dramatically increased video dynamic range, zebra display, time code, synchronization, and Sony’s proprietary Multi-Interface Shoe, which offers XLR audio input if you add the optional XLR-K1M adapter. And of course, the built-in electronic viewfinder means you can don’t need to buy an accessory viewfinder like you would with an HD DSLR.
I’m primarily a still photographer so forgive me if I glossed over the A7S video features a bit. Feel free to add your thoughts or anything that I might have missed in the comments section at the end of this article. I’d especially like to hear from pro videographers who can tell us how the A7S fits into the 4k video camera landscape. Is it an important addition- and if so, why? If it’s not a significant camera, tell us why not.

Sony Alpha A7S With 24-70mm f/4 OSS Zeiss Lens

My personal interest in the A7S, and the reason I got excited about it, was the potential for really high quality event shooting – and possibly low light sports photography. With the compact footprint of the Alpha A7 body, great low light image quality and useable AF in very low light, the A7S could be the best concert, tradeshow, party, street and photojournalism camera ever. Unlike a comparable pro DSLR, it’s small and discreet – but it can still perform. The only area where it doesn’t really measure up is serious sports shooting. With only contrast detect AF and a max burst rate of 5 FPS (single shot), it’s not going to really cut it for high-level action photography. But for almost any other low-light environment, the A7S looks like a ground-breaking camera. Yes, you do have to give up some resolution for the improved performance. But I think it will be worth it.

So far, pricing and availability information have not been announced. But I’ll be watching closely and let you know as soon as Sony makes those details available. There’s also talk of a new 28-135mm f/4 lens with power zoom in development. That would make sense since it would be a perfect all-purpose lens for the Alpha A7R. Once again, I’ll let you know when more information materializes.

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