Viewfinder and Rear Screen
The A7 III’s Electronic Viewfinder (EVF) is a 2.3 million dot finder with an expansive 0.78x magnification. The panel is the same resolution as the one in the A7 II, but the optics receive the same bump that the older A7R II received when it was released. While the resolution of the A7 III’s finder doesn’t match the upgraded 3.4 million dot finder in the A7R III, I find that it still looks quite good, and the large bump in magnification from 0.71x to 0.78x is a very welcome upgrade. The view is clear and absolutely huge. Unlike the A7R II’s viewfinder, however, the A7 III’s EVF maintains a clear view when using the magnifier for critical manual focus. The A7R II’s view became quite soft when magnifying the EVF image, but the A7 III maintains a nice crisp view. It would be nice to have the even clearer EVF that is included in the A9 and A7R III, but I suppose costs need to be cut somewhere.
The rear screen of the A7 III gains limited touch functionality, but in a cost-saving measure actually has a slight downgrade in resolution. The rear screen’s 921,000 dot resolution is a reduction from the A7 II’s 1.2 million dot screen. The screen is 3″ in size and can tilt up a bit more than 90 degrees and down by 45 degrees. The screen is a touch screen, but the touch implementation is quite limited at the moment. You can touch to select your focus point, and also double tap to zoom in while reviewing images, and then pan using the touch screen. However, menus can’t be operated by touch, and even a simple thing like swiping between images in playback mode isn’t supported. Still, it’s better than nothing, and it’s nice to see Sony finally start putting touch screens in most of their cameras. The rear screen is a bit of a letdown as far as quality is concerned, though…it’s middling resolution could be overlooked, but it’s also a bit dimmer and has fairly poor dynamic range, such that evaluating wide gamut scenes on the rear screen is somewhat inaccurate.
Autofocus
Perhaps the A7 III’s biggest upgrade from the A7 II is the autofocus system. When the A7 II was released, I praised its autofocus system as being one of the better ones in the mirrorless space at the time. However, after using the A7 II for nearly three years, some of the warts began to show with that system, and autofocus on mirrorless has come a long way. Upon release, the A7 II was OK at tracking motion, but certainly not excellent. It struggled at times in dimmer light, and it lacked the ability of later cameras to combine continuous autofocus and facial / eye tracking.
With last summer’s A9 release, Sony showed that mirrorless autofocus could truly be world-class, crafting what is likely the best AF system on any mirrorless camera, and putting the A9 on par with the best autofocus systems on ANY camera. In perhaps the biggest shock at announcement time, the A7 III inherits most of its autofocus DNA from the A9.
The A7 III has the same 693 phase detect AF points as the A9, albeit with a slower sensor readout. These AF points cover a whopping 93% of the image frame. Additionally, 425 contrast detect autofocus points help manage the excellent algorithms for face and eye detection while providing exceptional accuracy. The slower sensor readout does have an impact on the AF system, and as such, the A7 III isn’t quite up to the astonishing speed and accuracy that is featured on the A9. However, it is still very, very good.
In single shot autofocus, the A7 III locks very quickly and very accurately in most any light, with only minor slowdowns in very dim light. It’s a massive upgrade from the A7 II in lower light. Where hunting would occur with the earlier camera, the A7 III locks focus confidently and swiftly.
Continuous autofocus is also quite good on the A7 III. Lateral action is a breeze, and the A7 III can maintain accurate AF with this type of motion without breaking a sweat. In the more challenging motion toward the camera, the A7 III also does a very nice job, with around 90% accuracy on subjects moving towards the subject at reasonable focus distances. However, at very close focus distances (around 2.5m and closer), the slower sensor readout makes accuracy in this range far less predictable, while the A9 handled this situation without complaint. The change in motion is just a little too fast and the change in focus distance too far for the A7 III to maintain a solid lock on fast moving close objects. Those situations aren’t the norm, though, so in most real world situations, you’ll find no issues whatsoever.
Like with the A9, the standout feature of the A7 III’s autofocus system is the excellent Eye AF. EyeAF will find the nearest eye on your subject and track it, even in motion. The result is great accuracy for portrait or event work, as the EyeAF works very well in continuous AF, tracking the eyes even as a subject moves across the frame. It just ‘sticks’ to the eye. Honestly, it’s a revolutionary feature that leaves DSLR systems in the dust for ease of use and accuracy.
Performance and Dual SD Card Slots
While the A7 II never felt like a high performance body, I did feel that it had good performance, and was a relatively low lag body. The A7 III, however, makes the A7 II feel slow. Shutter lag is dramatically reduced from the A7 II, with extremely low lag and a quick, crisp shutter actuation. General operation of the camera is quick and sure, and doesn’t leave you waiting on the camera in most situations. Only if you’re a little quick on the image review button after snapping a shot will you have to wait a very short time to allow the file to be written to the SD card.
The A7 III receives a big boost in continuous shooting performance over its predecessor, with the camera able to shoot at 10 frames per second for over 110 compressed RAW files before the buffer fills. While the 10fps burst mode is certainly nice to have, I think most will opt for the slightly slower 8 frame per second mode when shooting action. When set to 10 fps, the camera will not show a live view, but rather a 10fps slide show of the previous image taken. This is fine for bursts of relatively stationary action, but it isn’t great for those where you’re tracking motion. At 8 fps, the camera shows a live view with minor blackout at each shutter click, and allows you to naturally follow the action. The large buffer ensures that you will always be ready for more shooting as well. In a nice touch, the camera can shoot at the same speeds when using the electronic shutter as you can with the mechanical shutter.
Sony’s two card slots sit behind a nice locking door in the hand grip. Like most cameras with dual card slots, you can choose how the files are written to the cards. You can have the second card as an overflow card, where the camera will begin using it once the first card is full; you can have the card set for backup use, where the same data is written to both cards. And you can have RAW written to one card and JPEG to the other. As one who shoots RAW+JPEG on Sony cameras (mainly to allow for WiFi transfer, which I’ll discuss on the next page), I choose this last option, with RAW files written to the first slot and JPEG to the second slot.
In many cases, it does pay to pick up a (rather expensive) UHS-II card for your new camera if you don’t already own one. The A7 III writes files to UHS-II cards dramatically faster than with older UHS-I Class 10 cards. I tested the burst rate with two different cards to determine both how many shots at 10fps in compressed RAW could be taken in a single burst, as well as how long it would take to write that full burst to the card. The results are as follows:
Sandisk Extreme Pro UHS-II (300MB/s): 111 frames, 24.8 seconds total (13.7 seconds to write buffer after it became full)
Sandisk Extreme Pro UHS-I (95MB/s): 84 frames, 31.9 seconds total (23.5 seconds to write buffer after it became full)
As you can see, having a UHS-II card not only allowed for nearly 30 more frames to be shot before slowdown, but once the buffer was full, it cleared nearly twice as fast.
However, when shooting with both cards in the camera, and writing JPEGs to the slower card in slot II, write times are slowed down to match the UHS-I speeds. A 10 fps RAW+JPEG burst could rattle off 78 frames before the camera slowed down, which then took 36.5 seconds total (including the burst), which is 28.7 seconds to clear the buffer. There was no difference when using two UHS-I cards.
As such, if you write data to two card slots simultaneously, you entirely lose the benefit of the faster card slot. It is somewhat baffling why Sony would only equip one of the two slots with UHS-II capability. However, the huge buffer nullifies this issue for most people, as the only time I ever filled the buffer and had to wait a few seconds before shooting again at full rate, even when using both card slots, was when I was intentionally testing how big the buffer was.
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