The Sony Alpha a7S Mirrorless Digital Camera features a full-frame 12.2MP Exmor CMOS sensor and BIONZ X image processor to enable notable video and still image quality with an expansive dynamic range, low noise, and extended sensitivity to ISO 409600. At the sensor level, this full-frame sensor features a unique on-chip gapless lens design, which incorporates small lenses between neighboring pixels in order to increase light-gathering effectiveness and promote greater image quality across the entirety of the sensor plane.
Check Out: Best Lenses for Sony A7S
Sony Alpha A7S: Price
The sensor and processor combination also avails a wealth of speed throughout the camera system, including a top continuous shooting rate of 5 fps, support for 4K video recording, and a fast 25-point contrast-detection AF system with sensitivity to -4 EV.
Beyond its still image performance, the a7S is also quite adept in regard to recording video. It is able to output uncompressed 4:2:2 UHD 4K video to an optional external recorder over HDMI, as well as record full HD 1080p video in the high-quality XAVC S format at 50 Mbps in multiple frame rates.
Extending the video recording capabilities is support meant for S-Log2 gamma, which helps to increase the effective dynamic array during recording, and also picture profile options, time code, and zebra marker display aids. Sound can be recorded in the AAC/Linear PCM format via the internal stereo microphone, with a built-in headphone jack for on-board monitoring, or via an exterior microphone.
Rounding out the a7S’s imaging capabilities, both a 3.0″ 921.6k-dot tilting LCD monitor and 2.36 million-dot OLED electronic viewfinder are available for image monitoring and review. Built-in Wi-Fi connectivity, with support for NFC, is available, too, for instant sharing of imagery from the camera along with remote camera control from a linked mobile device.
Full-Frame Exmor Sensor and BIONZ X Image Processor
Incorporated within the sleek body design is certainly a 12.2MP full-frame Exmor CMOS sensor and BIONZ X image processor, which work together to allow an expansive powerful range with minimal noise and notable sensitivity. The a7S includes a native sensitivity range from ISO 100-102400, which is further expandable to ISO 50-409600. Coupled with the large individual pixel size the 12.2MP sensor affords, this camera is well-suitable to use in low-light conditions.
The sensor’s design also features a new-generation RGB color filter array, as well as a gapless on-chip lens design. Together, these two technologies enable truly efficient light-gathering capabilities that additionally reinforce the low noise, high-sensitivity style. Furthermore, an anti-reflective coating has also been applied to the seal glass of the picture sensor to minimize surface reflections, glare, and ghosting for contrast-rich, color-neutral imagery.
The sensor and processor mixture also avail an abundance of performance-related benefits to still shooting, including a Swiftness Priority continuous shooting rate of 5 fps, or a 2.5 fps shooting rate with continuous AF. The contrast-detection AF system employs 25 distinct points to quickly and exactly acquire focus in light levels as low as -4 EV to support working in a wide variety of shooting conditions.
Full Pixel Read-Out with Clean HDMI Out for 4K Recording
Line-Skipping offers been the Achilles Heel of video recording DSLR and Mirrorless cameras since video recording was first introduced. Most full-frame and APS-C still digital cameras have extremely high pixel counts, which is great for still digital photography, but makes utilizing the whole sensor technically infeasible when documenting video since scaling down, say a 36-megapixel image in real-time would require a much more expensive image processor and generate more heat than such a compact body could handle.
So traditionally these cameras skip lines when recording video, leading to major aliasing and moiré from the large sample gaps in addition to decreased resolution and increased noise. However, the lower quality sensor of the a7S is created for video recording and features a full sensor readout without any line skipping. This means you will see a sharp image devoid of major aliasing and moiré whether documenting internally at 1080p or externally in UHD 4K.
For times when the high quality 50 Mbps XAVC S Codec is not enough the a7S is able to output uncompressed UHD 4K (3840 x 2160) at a 4:2:2 color depth over HDMI to compatible third party recorders. Or, if recording internally to a memory space card the HDMI can output 1080p at 4:2:2 for external recorders or HD monitors that don’t support 4K inputs.
Sony Alpha A7S: Key Features
- 12MP full-frame EXMOR CMOS sensor
- Focuses at light levels to -4EV
- 1080 footage at up to 50Mbps (XAVC S)
- Extensive movie-focused capture options: S-Log2, Black Level, time code
- Video ISO Range 100 – 409,600
- Uncompressed 4:2:2 Full HD and 4K video output over HDMI
- 2.36M dot OLED viewfinder
- Mic and headphone sockets
- 720/120p option for slow-mo capture
- Wi-Fi with NFC
Sony Alpha A7S: Pros
- Impressive image quality
- Superb, detailed, essentially moiré-free 1080p footage
- Outstanding 4K (UHD) video when used with external recorder
- Useful, high resolution electronic viewfinder
- Completely silent shooting available
- Microphone and headphone ports
- Useful tools, such as focus peaking and zebra pattern (work well with non-native lenses)
- Picture Profile/S-Log2 mode allows lots of DR capture for color grading
- Exposure compensation dial makes Auto ISO usable in manual mode
- Solid Wi-Fi system allows for remote shooting and easy photo sharing
- Classic Sony features (HDR, Sweep Panorama) work well
- Charging via USB can be convenient
- External charger makes it easy to keep second battery charged
Sony Alpha A7S: Cons
- Limited to contrast-detect AF, while a7/II siblings have on-sensor phase-detect AF
- Lower dynamic range and resolution than immediate competitors
- Sony’s Raw compression scheme can lead to posterization at high contrast edges
- Small battery can be restrictive, especially for video shooting
- Lack of touchscreen
- Fixed Auto ISO behavior (no programmability or rate-of-change options)
- 4K (UHD) video requires external recorder
- SLog2 profile only offers a rather high minimum ISO, which can be limiting
- 4K footage from APS-C region of sensor is disappointing
- Overly sensitive eye sensor (also stays active when screen is tilted)
- Lacks a built-in flash
Sony Alpha A7S: Conclusions
The more I use the a7S, the more I am sure it was made for recording. It has big pixels and creates clean and informative video even in low light. A stills camera is less convincing than a video camera, and its ergonomics aren’t a perfect fit for videography. It doesn’t have 4K footage. What it does have is a lot of video and picture shooting modes, and what it actually does is cram a ton of video and photo-taking capabilities into a tiny frame.
Film photographers, film stars, and indie filmmakers will find a lot to appreciate in this camera. The a7S offers an undeniably dramatic look that’s incredibly difficult to attain without walking up to a more expensive frame.