Sony α7 II v Sony α7 S

Sony launched the α7 II last month and α7 S last June. Both are reasonably priced full-frame mirrorless cameras, but they are targeted at completely different users.

Main differences

The a12.2-megapixel count of the α7 S full-frame image sensor might appear humble, but it is able to accommodate high sensitivity settings of up to ISO 409,600.

In contrast, the α7 II, with its 24.3-megapixel full-frame image sensor, has a maximum ISO setting of 25,600, which is four stops fewer.

The α7 S is able to shoot 4K (4,096 x 2,160 pixels) videos with a compatible 4K recorder aadaptor. But it is disappointing that you still require a 4K recorder adaptor, when Micro Four Third mirrorless cameras, such as the Panasonic Lumix DMC-GH4, can shoot 4K natively.

Both α7 cameras, however, can record full high-definition (FHD) videos in XAVC S codec, which has better details and fewer compression artefacts because of its 50Mbps bitrate.

The α7 II uses a 117-point phase-detection autofocusing (AF) system along with 25 contrast- detection AF points and an advanced algorithm that speeds up its AF responsiveness by 30 per cent, according to Sony.

The α7 S has only a 25-point contrast-detection AF system.

Moreover, the α7 II is the first full-frame mirrorless camera to have an in-body optical 5-axis image stabilisation system.

Build and handling

Both cameras have tough bodies of magnesium alloy which resist dust and moisture. Both are equally compact, in comparison with full-frame cameras.

The α7 S has essentially the same body design as the original α7, whereas the α7 II is slightly bigger - 12mm thicker, and heavier by 110g because of some cosmetic changes.

But the α7 II has a larger grip and a more contoured rear thumb rest that allows for a more secure hold on the camera. The rear is also slightly thicker.

The button layout is slightly different from previous α7 models. The metallic front and rear command dials are gone. Instead, there is a rubberised command dial in front of the grip, where the index finger usually rests, while a rubberised rear command dial is sited near the thumb rest.

The α7 II's shutter release sits atop the grip instead of on the right of the body. This puts all the important controls within easy reach and you can change settings more quickly.

On the camera's top right, there are now two customisable function buttons instead of one, to accompany the Mode dial and the exposure compensation dial.

The rear button layout, with its intuitive clickable wheel dial, sees only minor changes. The α7 II's right wheel dial click is for ISO settings instead of white balance.

I prefer the α7 II even though it is heavier and thicker, because it provides a better grip and its button layout is slightly more intuitive.

Operation

Though the α7 II is supposed to power up faster, both cameras seemed to start up in about 1.7sec (from turning on the power to the LCD screen lighting up) and shut down in about 1.4sec.

Most mirrorless cameras usually power up and down in around 2sec.

Using the same SD card with a writing speed rated at 30MB per second, the a7 II captured 27 RAW images in 5.7sec before the buffer ran out. The α7 S came close, with 28 RAW images in 5.8sec.

With the same Sony FE 24-70mm f/4 lens, both α7 cameras lock on to a focus almost instantaneously in bright sunlight. In dim conditions, the α7 II took about 1sec to focus with the aid of AF Assist light, while the α7 S took about 2sec.

With its additional 117-point phase-detection autofocusing (AF) system, the AF of α7 II feels faster in tracking moving objects.

I tried shooting at a slow shutter speed of 1/6sec, with both cameras handheld using the same aperture and ISO setting to test the in-body image stabilisation. There was less camera shake in the α7 II pictures.

Image quality

Both cameras have fantastic image quality with sharp rendition of pixels and smooth skin tones. The details rendered are just incredible, especially when you zoom into the picture. You can see the leaves on a tree clearly even when they are at the side of the frame. Corner-to-corner sharpness is superb.

The only advantage of the α7 II - with its bigger megapixel count - is that you can have a bigger printout of the same scene.

In terms of image noise, both did equally well. You cannot find any noise artefacts even at ISO 3,200. At ISO 6,400, the α7 S images exhibited fewer noise artefacts, possibly because of its lower megapixel count.

Video quality

In the FHD video recordings, both cameras did equally well. Both also picked up a big chunk of ambient and wind audio. During video recording, both cameras re-adjusted their AF within 2sec when panning to a new scene. Videos shot with the α7 II showed less camera shake.

Battery life

The α7 S wins this test by a small margin. On a full charge, it amanages about 380 still images, while the α7 II is able to shoot only 350 still images.

By mirrorless camera standards, their battery life is decidedly average. You will probably want to carry an extra battery with you, if you plan to shoot for a whole day.

• If I had to choose between these two Sony cameras, I think the α7 II would represent greater value for money because of its lower price, better handling and in-body image stabilisation system.