Sony a7R IV: What you need to know

  by Richard Butler

Intro

The Sony a7R IV is the company's fourth-generation ultra-high-resolution full-frame mirrorless camera. It's built around a new 61MP back-side illuminated CMOS sensor. It's the first new sensor in an 'R' camera since 2015.
The new chip has 567 on-sensor phase detection points, which cover 99.7% of the sensor's height and 74% of its width, meaning you get depth-aware focus across a huge range of the sensor.
The camera uses the same front-end LSI and Bionz X processor as the a7R III. Sony says it knew there was a 61MP sensor coming from Sony Semiconductor, so was able to design these chips in anticipation of it.
The higher resolution of the chip means you still get 26MP images, even if you use an APS-C crop. Naturally, you get fewer PDAF points (325 in this case), but in exchange you get nearly 100% frame coverage.

AF Improvement

In addition to having more AF points than its predecessor, Sony has also added improved tracking modes to the a7R IV. The camera will now track subjects as soon as you half-press the shutter button, whether it's looking at eyes, faces or a subject you've selected. It can do all while shooting 10 fps bursts or when capturing video. In addition to people, the a7R IV can also detect animals.
As you'd expect from a pro-grade camera, there's a menu option to hide any AF area modes you don't regularly use. And, given our experiences with the latest tracking modes, that should mean 'most of them.'
A couple of small changes we're pleased to see are the choices over whether the AF point appears as white or red (it was a rather recessive grey on previous models), and how the camera controls its aperture as it focuses. A new 'Focus Priority' mode prompts the camera to acquire focus with the aperture wide open, which is especially useful when shooting a small apertures in low light conditions, where the camera could otherwise struggle. This comes at the cost of slightly increased shutter lag, since the aperture still has to stop-down when you fully press the shutter.

Multi-shot modes

The Sony a7R IV builds on the multi-shot high-res mode offered on the previous model. The latest version will shoot up to 16 images. It moves the sensor by 1/2 a pixel each time, with the net effect being that it shoots four groups of four images: four images to fill-in the color gaps left by the Bayer color filter pattern shot in four positions to increase the overall spatial resolution.
This means capturing 960MP-worth of images to produce a 240MP final image with full color information at every pixel (and the tonal information/noise gain that comes from shooting 16 images).
The a7R IV also offers the simpler, quicker, four-shot, Bayer-cancelling mode offered by its predecessor.
Both modes use the camera's electronic shutter. Both require the resultant Raw files to be assembled using Sony's Imaging Edge software, so you can't preview the results on the camera.

Ergonomic changes

The first thing you'll notice about the a7R IV is that it has a higher-resolution viewfinder. It uses the 5.76M-dot finder we've seen in a number of cameras, such as the Panasonic S1/S1R. As with previous Sony cameras, you have to choose whether to prioritize resolution or refresh rate of the finder, depending on the demands of what you're shooting.
Other ergonomic changes include a deeper, more substantial grip, a redesigned rear dial on the top plate of the camera, along with more substantial AF-On button and rear joystick 'nub'. There's also now a lock on the exposure comp dial, to prevent accidental operation. It's a toggling lock, so you can leave it popped-up when you're using the camera, then lock it down when stowing it in a bag, with the certainty that you won't dial any extra compensation in, as you grab the camera to use it.
As with the A7R III, the IV has dual card slots, but now both of them support UHS-II. It also has a USB-C port, which you can for charging or tethering to a PC.
The a7R IV is also the first Sony Alpha to accept a digital audio input. This is achieved via a new version of the Multi-Interface Shoe (the series of connection pins at the front of the hot shoe). For now, this can be delivered by an external shotgun mic and updated version of Sony's XLR adapter that have analogue-to-digital converters built into them.

Construction changes

Like its predecessors, the a7R IV is made primarily from magnesium alloy. However, Sony says it's done work to enhance the dust and moisture resistance of the new body. There's a foam gasket around the battery door and the edges of the card door, to prevent water ingress.
The rubber port covers have also been redesigned: the ports now have lips around them, which engage with the port covers. This is designed to create a more complex pathway that water would need to work its way through, to enter the camera. We wouldn't go so far as to call it labyrinth sealing, but it's still and improvement.
The Mark IV uses the same NP-FZ100 battery as before, and is able to match its predecessor's 530 shots-per-charge battery life figure when using the EVF. Shooting with the rear LCD actually sees a 20 shot-per-charge jump compared with the a7R III, now achieving a pretty respectable rating of 670 shots. As always these numbers don't necessarily reflect how many shots you'll get (it's not uncommon to get double the number of shots), they're best thought of as a yard-stick for comparing cameras.

Video

What's most interesting is how little has changed in terms of the camera's video capabilities. On the plus side, the a7R IV can shoot both 24p and 30p footage from the full width of its sensor. This doesn't use full-pixel readout (multiple pixels are 'binned' together), but it means you get to retain the full angle-of-view offered by the lens, notwithstanding the crop from 3:2 down to 16:9.
As with the a7R III, you get more detailed 4K footage by shooting in Super 35 mode. The good news is that the 24p footage is now taken from 6K footage (1.5x oversampling in each dimension). The not-so-good news is that the 'Super 35' mode now has a 1.6x crop for 24p and a 1.8x crop for 30p (ie a 1.1x crop and 1.2x crop, relative to what you'd expect). This has at least some negative effect both in terms of achieving a wide angle-of-view and in terms of image quality.
So, not only is there no 4K/60p on the a7R IV but the camera remains a strictly 8-bit video camera. Most rivals now offer 10-bit capture or output: something that gives a significant boost in terms of editing flexibility to Log footage, so it's odd not to see it here.

What's not changed

We're a bit disappointed to see little work done on the camera's menu structure. It still features very little in the way of signposting, to help orient you in the menus and find your way to the options you're looking for. You'll frequently need to simply memorize where settings live, which ideally wouldn't ever be the case. Like its predecessor, you can at least create a 'My Menu' tab to cluster-together all the settings you use most often.
One definite improvement is the ability to define different Fn menus for stills and for video shooting. Oddly, though, the Fn menu still isn't touch-operable, which still catches us out the first couple of times we pick up the camera, partly because the Fn menu looks like a series of buttons waiting to be pressed, but mainly because this is how modern cameras work.
There's also no change on the Raw side of things. The camera offers 14-bit uncompressed Raw (that '15 stops of DR' figure Sony is advertising is with downscaled, 8MP images) or compressed Raws that use Sony's potentially destructive compression. There's still no lossless or visually lossless compression option.
Another function that pretty much all of Sony's rivals offer but is missing here is the ability to process the camera's Raw files in the camera. This isn't a feature everybody's going to need, but there are times it'd be helpful to be able to try applying different color or sharpening settings to a file before outputting it.

What this says about the future

At the risk of attempting tasseomancy, it's perhaps interesting to read into the a7R IV and assume that the changes we're seeing here are likely to be reflected in the next generation of Sony cameras.
The decision to stick with 8-bit video output could indicate that competitive space is being left for the long-expected a7S III. Or it could simply indicate that Sony doesn't believe there's demand for more extensively editable 10-bit video from its audience.
The relatively minor changes to the camera's UI, despite the recognition of the need to update the ergonomics, is also something that's likely to get carried-over to other forthcoming cameras. Again it looks like Sony is more focused on adding attention-grabbing new features (and, to be fair, Full-time Eye AF / Full-time Tracking are very impressive), rather than resolving existing quirks and foibles.
While the a7R IV helps nudge Sony to the front of the pack, it doesn't look like as big an upgrade as we're used to seeing between whole version numbers. Equally, it perpetuates a handful of irritations that have persisted for multiple generations, now.

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