Major components of the Sony aR7 II mirrorless digital camera

Teardown: Sony aR7 II mirrorless digital camera

Sony pushes the envelope but keeps things tight.

Mirrorless cameras make up an important growth segment for the digital camera market as it seeks to compete with the increasing photographic capability of smartphones.In simple terms, by rendering the preview image directly from sensors to displays - either small ones within a traditional form factor viewfinder or the larger ones already common on the back of a camera’s body - mirrorless products can be smaller, lighter and cheaper than their mirrored SLR equivalents. They nevertheless allow users to fit different lenses to the body (‘mirrorless’ is now the accepted name for what used to be known as ‘mirrorless interchangeable lens cameras’.

The NPD Group, one of the leading analysts tracking the segment, estimates that mirrorless products accounted for 26 per cent of all camera sales outside the US in the year to end-April 2015, but only 16 per cent within the US - hence the perceived opportunity for growth (although sales in Europe have recently slowed down).

Most mirrorless cameras are sold to casual photophiles, but as an emerging segment there is strong competition between the leading hardware players at the professional end. This serves to both establish broader technology leadership and meet the demands of hardened snappers for higher resolution, fidelity and quality, as well as lower excess baggage bills.

Sony’s a7R II body is one of this year’s most hyped entrants at the top of the mirrorless market. It costs £2,800, enough to make anyone but a semi-pro user baulk, but for those who need a camera that really does perform, the Japanese giant has thrown in just about everything.

Resolution for the updated Exmor R CMOS sensor is 42.4MP (the earlier a7 came in at 24MP). This is less than the 50MP offered by the Canon 5DS R, but Sony is claiming a first in boosting its sensor with full-frame backside illumination (BSI). BSI helps the sensor perform better in very low light and makes it quicker at offloading images for high-frame-?rate video and still bursts.

Similarly, Sony says that it has located the photodiodes on the new sensor much closer to the on-chip lens, further increasing the efficiency of light collection.

The sensor is then mounted on a five-axis SteadyShot stabilisation cradle. During its teardown, iFixit analysed the clever electronics involved to achieve this. It notes: “the central tray of the stabiliser holds the image sensor, and is home to three electromagnets, each a component of a voice coil, an electromechanical device used for incredibly fine positioning (voice coils are also found in platter hard drives, controlling the read/write arm).

“These coils live in the magnetic fields of their permanent magnet buddies - which means slight variations in power to the three coils generates forces in a variety of directions. Enough variety to adjust the sensor on five distinct axes. Not a small feat for a full-frame camera.”

Fidelity to real life via the viewfinder or display is carefully replicated. The viewfinder comprises a 1.3cm XGA OLED display cramming in 1,024×768 pixels, 2,560ppi to account for the much closer proximity of the human eye. The 6.35×4.44cm TFT LCD display has resolution at 270ppi, still high-density given, again, the likely viewing distance.

Auto-focus has been enhanced from 25 to 400 phase-detection points. Then, as is increasingly commonplace, the a7R II offers both Wi-Fi and NFC connectivity.

In terms of the hardware design, this is a complex beast with a lot of PCBs, and iFixit noticed scratchmarks hinting at a tricky assembly process. In pulling out the various boards that service RF, displays, image capture, image processing and mechanical functions, the teardown team encountered what felt like “every ribbon cable created since the dawn of time”. And as for putting the camera back together: “Answer: most likely unicorn magic.”

As such, iFixit scores the a7R II at just 4 out of 10 for repairability. “Accessing anything inside the camera requires removing the complex rear LCD panel first,” iFixit concludes. “Internal components are very intricately organised; repair without a service manual would be very difficult.”

Yet, it also describes the camera as a “mighty feat of modern engineering”.

We need to remember what Sony is trying to do here, pushing a relatively new technology to the next level, particularly with its use of BSI. Moreover, weight still matters, even for a professional camera.

The a7R II body comes in at just over 580g. Obviously lenses can add to that considerably, but if Sony and its rivals are to convince professionals to trade across to the new technology, heft remains a key differentiator. Every PCB has to be squeezed in to do its job at the minimum penalty.

Pro reviews for the a7R II have been almost universally positive, albeit with some caveats. Some moiré and noise effects have been noted, as have diminished highlights attributed to a trade-off needed to implement BSI. There’s some disappointment over battery life, but with the acknowledgement that Sony has stuck with the same cell as in earlier models: valuable for users who need to buy multiple bodies.

In short, it’s a benchmark-?setting camera. Just don’t assume it’s ruggedised, because fixing it won’t be a snap.

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