The Sony a7R IV is the latest high-resolution full-frame mirrorless camera from Sony, as is evident from its R suffix. It is targeted more at portrait, commercial and wedding photographers. For this review, I used the camera with a Sony FE 24-70mm f/4 lens.

Major improvements over its predecessor, the a7R III, include an image sensor with a megapixel count of 61 megapixels (up from 42.4 megapixels), an electronic viewfinder (EVF) with a resolution of 5,760,000 dots (up from 3,686,400 dots), and an updated autofocusing (AF) system that is better at tracking faces and eyes for both humans and animals.

Previously, only one of the two SD card slots supports the faster UHS-II format. Both support the format now.

Otherwise, the a7R IV still offers the same 10 frames per second shooting speed, 4K 30p video recording and in-body image stabilisation of its predecessor.

The design also does not differ much from its predecessor's, especially in terms of button layout. This is a good thing, as all the buttons and dials are all within easy reach of your fingers, making it easy to operate the camera. For instance, the joystick, sited just above the rear command dial, allows you to move the AF point quickly.

However, the grip is more pronounced and contoured than its predecessor's, which makes it a joy to hold the camera. On the flip side, if you are using a big lens, your fingers might rub against the lens when using the grip.

Still, it provides superb handling. If you want even better handling, get the vertical grip VG-C4EM ($549). Not only does the vertical grip offers a quick and easy way to switch to portrait orientation, it offers an additional battery slot for longer battery life.

Operation is pretty swift. The camera starts up in 1.1 seconds and shuts down in 1.3 seconds. Most mirrorless cameras take around two seconds for each operation.

Using an SD card with a writing speed rated at 299MB per second, it was able to shoot 124 RAW images in 7.7 seconds before the buffer ran out. This shooting speed and buffer capacity put many high-end DSLR cameras to shame.

Not to mention, the a7R IV achieves sharp focus on subjects almost instantaneously under bright sunlight. In dim lighting conditions, it takes at most one second to secure a focus with the aid of the AF assist light.

The Eye AF feature works superbly, even with animals. I was able to capture a beautiful stray cat in sharp focus even though it was moving around.

As you might expect from an a7R series camera, the still image quality is excellent with sharp rendition of details. Colours are vibrant and skin tones are accurate.

And to take things up a notch, there is its Pixel Shift Multi-shot mode, which combines 16 shots to create a 240-megapixel image. But the subject has to be absolutely still, or you will get artefacts caused by moving subjects.

Noise performance is on par with its predecessor, which is stellar. Image noise is non-existent until ISO 3,200. At ISO 6,400 and above, detail loss is more evident, especially in the dark areas. But even at ISO 12,800, images are still good enough for social media use. However, images shot at above ISO 12,800 looks washed out with distinct detail loss and clear chromatic noise artefacts.

Using the a7R IV with Sony's ECM-B1M shotgun microphone ($479) to record interviews for a recent story I was working on, I found the movie and audio quality to be top-notch.

On a full charge, the a7R IV can shoot around 530 still images, around the same as its predecessor and better than most mirrorless cameras, which average around 300 shots.

I also like that the camera can be charged via a USB-C port, which means one less charger to bring along for your travels.

The a7R IV costs $300 more than its predecessor, which really isn't much considering all the improvements.

Still, at nearly $5,000 for the camera body alone, it is a serious investment. But if you can get past its hefty price tag, thisa is one camera that will not disappoint.