
To say I was a bit surprised to learn that Sony's latest full-frame release was the a7R IV would be an understatement. There were plenty of other picks that I thought would be upgraded first (a7S III anyone?). Fortunately, this is no minor tweak, even though it may look like it on first glance. We are seeing a brand-new 61MP CMOS sensor, an updated physical design that signals it may be the fourth try that is charmed, and various other improvements that make this camera worth a look for many photographers.
Doubling Down on Resolution
When the original a7R was first launched, it was obvious the "R" stood for resolution. It had, at the time, a class-leading 36MP sensor. Keep in mind, this is back when Canon's flagship 5D Mark III was only boasting 22MP. Sony has nearly doubled that resolution in the relatively short time frame since that launch.

61MP can be overkill—stick with the a7 III if you need something more well-rounded. For photographers who can make use of the extra pixels, it is invaluable. We are talking studio or landscape and architectural photographers. The extra resolution isn't a negative in these situations, generally with good lighting and a tripod, and can come in handy when working on the images in post-production. It is still fun to snap a photo and then just keep on clicking that magnifier just to see how close in you can get before the image becomes pixelated.
Taking some quick photos on a tripod definitely shows off this extra detail. I would highly recommend this for studio use. There is also a massively upgraded Pixel Shift Multi Shooting mode that can create a 240MP image with full RGB color. This is the best you can get from any camera that uses a similar system. However, it requires a still subject and camera, meaning no exciting handheld shots with boosted resolution, though one could argue that there is no need for increasing the resolution with regular handheld shots, because 61MP is plenty.
With extra resolution are a couple of drawbacks. The most noticeable is to low-light performance, because the smaller photosites are not quite as sensitive as larger ones. You'll see noise creep into your images earlier than on the a7R III if you make a direct comparison. Sony still manages to keep noise very manageable, so as long as you don't work exclusively at night, you shouldn't be too concerned.

The other potential downside is the greater potential for camera shake to impact image quality. When you have greater resolution, you will notice smaller movements showing up in your images. The easy fix is to bump the shutter speed up a bit, though this means less light hitting the sensor, which compounds on the previously mentioned decrease in sensitivity.
On the other hand, dynamic range is outstanding. The newer sensor design and improved processing have led to the a7R IV being able to capture an incredible dynamic range, up to 15 stops if Sony's marketing is to be believed. Images look great and they are quite malleable in post.

A (Slightly) Redesigned Body
My first a7 series camera was the original a7S and, while its ergonomics weren't bad, they certainly weren't great. With each successive release Sony has made adjustments to make its cameras easier and more comfortable to use. The a7R IV is easily the best yet. The grip is larger and more contoured, the ports have better flaps that don't just hang in the way, and there are matching UHS-II SD card slots. Everything seems to have gotten a minor tweak for the better.
One thing Sony cameras have been dinged on in the past is weather sealing. While no company will give you some solid numbers or data about what exactly that means, Sony is saying that the a7R IV is top of the line when it comes to sealing and durability. Considering I haven't seen any issues since the a9 and gen III a7 series cameras, this is believable, and a huge plus if you are considering upgrading from an older model.
My favorite change comes to the electronic viewfinder because it now has a boosted resolution of 5.76m-dot and a high-quality setting for a refresh rate of 120 fps. Images are crisper and smoother, exactly what you want from an EVF. I think I can comfortably say that current top-of-the-line EVFs are better than the optical finders of DSLRs. This isn't an unprecedented resolution; many other camera makers have implemented it already, but it is nice to see it show up on the a7 series.
Another change comes to the Multi Interface Shoe. A little surprising, right? Well, it’s minor but important, because it helps those looking to use this for professional video applications who need a complete system with high-fidelity audio recording. Essentially, the new shoe will accept digital audio input directly from select devices for cleaner audio that no longer has to go through an analog-to-digital converter, or ADC. At launch, Sony has two accessories that support this function, the unique ECM-B1M Shotgun Microphone and a new XLR-K3M XLR Adapter.
Finally, the last thing I want to talk about is wireless capabilities. Built-in Wi-Fi and Bluetooth are here, as expected, with added support for 2.4 GHz and 5 GHz Wi-Fi. This enables wireless tethering and should open the door for cleaner shooting scenarios in the studio or on location.
Conclusions
I’m most definitely upgrading my a7R III to the new a7R IV—the extra resolution and modified body are enough to convince me. What about you? Are you going to upgrade your camera system or are you thinking about your first mirrorless? Be sure to let us know your thoughts in the Comments, below, and tell us if you want to see a longer review, which would include video performance, Pixel Shift, and many of other new features.
2 Comments
I shoot birds in flight. I have heard some bad things about the buffer in this camera. How about it. If I shoot of 20 to 30 images, will I have to wait for them to load before shooting again?
Bill, I have done a lot of wildlife photography, and some birds, formerly with Canon and more recently with Sony. I have the a7R4 and the a9 (waiting for the new a92). I have tried to used the a7R series for quick motion, including the a7R4, but this is not its best fit. The a9 and the new a92 are far superior... better at less light (i.e. high shutter speeds), much better at focusing and tracking moving subjects, etc. The images from the a9 are astoundingly sharp, and even at 24MP you can make amazing large prints. I generally use by a9 for action, motion, low light, and reserve the a7R4 for landscape, tripod, good light, etc. 61MP in a full frame is pretty extreme, and you really need everything to be perfect to fully take advantage of it. Note that the current a9 has the same sensor as the a92. The latter is an incremental upgrade so if price is a consideration you can get a great deal now on a used a9 that is almost as good as the a92. Price not too much of a concern try the a9. You may wish to rent each and give them a test drive.