The a7R is a strong performer in most respects, with responsive autofocus and reasonable continuous shooting speeds (for its resolution). On the other hand, it's quite slow to start up, and battery life is comparatively low.
While most mirrorless cameras start up in under a second, the a7R isn't ready to shoot for a little over two. We've also noticed that if the power is quickly cycled, the delay can be twice that. Interestingly enough, the camera is ready to shoot in nearly half a second with no lens attached, so the delay may have something to do with initializing the lens.
As one would expect, there's no noticeable shutter lag on the a7R. In terms of shot-to-shot speeds, you'll wait around 0.8 seconds between Raw+JPEG shots, and slightly less if you're sticking to JPEG.
AF System & Performance
Unlike the a7, which has a 'hybrid' autofocus system, the a7R sticks with a more conventional contrast detect setup. The camera has a total of 25 focus points to work with, and from our experiences, its focusing performance is on-par with DSLRs in good light, and a bit slower than the best mirrorless models.
In low light, however, the camera can struggle to focus - unless you are mindful to set the AF point over a contrasty area. If you do so, we've been very pleased by the camera's autofocus accuracy in shot after shot.
The a7R offers two different continuous shooting modes: standard (1.5 fps) and speed priority (4 fps). As its name suggests, speed priority mode shoots faster than regular continuous, but for a much shorter duration.
Here's what kind of performance you can expect from the two burst modes on the a7R. We used a SanDisk Extreme Pro (95Mb/sec) SDHC card to measure the speed.
Large/Xtra Fine JPEG
|Frame rate||1.6 fps||1.6 fps||1.6 fps|
|Number of frames||37 shots||35 shots||22 shots|
|Buffer full rate||1.0 fps||1.0 fps||0.8 fps|
|Write complete||15 secs||8 secs||14 secs|
The a7R hits its advertised speeds in its standard continuous mode, and its large buffer size allows you to shoot at full speed for quite a while. Clearing the buffer can take some time, during which time you cannot enter the menus or playback mode. For JPEG shooting, this delay depends on the number of photos you've taken. For example, the a7R is locked up for 15 seconds when forty-three JPEGs are taken. This gets worse or better depending on the speed of the card. We recommend using the fastest card you can find, as the a7R's files are understandably large.
The view on the LCD/EVF is in real-time when shooting in standard continuous mode.
Speed Priority mode
The speed priority continuous mode lets you shoot at rates of 4 fps according to Sony. By default, the camera locks focus on the first shot, but on the a7R you can turn on continuous AF, if you wish. Here's how the Alpha 7R performed at its faster speeds:
Large/Xtra Fine JPEG
|Frame rate||4.3 fps||4.1 fps||4.3 fps|
|Number of frames||15 shots||16 shots||14 shots|
|Buffer full rate||1.1 fps||1.0 fps||0.9 secs|
|Write complete||14 secs||8 secs||14 secs|
The a7R also beat Sony's estimates in Speed Priority mode. The number of shots per burst is about half that of in regular continuous mode, but the buffer-full rate and 'locked up' times are the same. The a7R does not provide live view in Speed Priority mode.
The a7R uses the same NP-FW50 InfoLithium battery found on many other Sony cameras. The NP-FW50 has 7.7Wh of energy, which Sony claims will provide 340 shots per charge. That's very low, considering the a7R has no built-in flash, which is normally included in the CIPA battery life numbers. Do note that using Wi-Fi frequently will put extra strain on the battery.
Despite the cost of the a7R, Sony does not provide an external charger. Rather, you use an AC-to-USB cable (or just your PC) to fill up the FW50 battery. Charging via the USB adapter takes a whopping 310 minutes, so it makes a lot of sense to pick up one of the BC-TRW or BC-VW1 external chargers, which are both considerably faster (especially the latter).