Gear Reviews

Sony a7 IV v Sony a7 III: 9 key differences

How does Sony’s latest all-rounder full-frame mirrorless compare against the camera it replaces?

Sony’s a7 series arguably offers the best value camera from the brand’s range of full-frame mirrorless devices, serving up an excellent balance of resolution, speed and video specs. While Sony photographers have been enjoying the a7 III since 2018, we all know the brand updates its camera regularly and 2021 saw the launch of the new model – the Sony a7 IV. But how exactly does this new model compare against the a7 III? Well, to help you make a more informed buying decision, we’re diving deep into the specification sheets to compare the features and functions…

One – Resolution:

The Sony a7 III offered photographers 24-megapixels of resolution, which is a decent figure when you add in the speed of the camera’s burst rate (see below). However, Sony has managed to squeeze even more pixels out of the a7 IV’s full-frame Exmor R CMOS sensor, serving up 33-megapixels. This huge jump in megapixels is a big deal and opens up the camera to a whole new audience of photographers who demand higher resolution – for example landscape and wedding photographers, who will appreciate how the extra megapixels will allow for more tolerance when cropping images and will enable them to make bigger prints – well in excess of A3.

Two – Improved IBIS:

Sony has long championed In Body Image Stabilisation (IBIS) and the Sony a7 III did a fantastic job with its five-axis system, which delivered 5-stops of compensation. This can make a real difference out in the field – especially when shooting in low light conditions where longer shutter speeds can result in camera shake becoming an issue and frames suffering from blur. Well, the a7 IV sees an incremental upgrade in this area, increasing the compensation to 5.5-stops, a small improvement, but every little helps in this area. 

Three – Burst rate:

While no camera from the a7 series is able to match the lightning speed of Sony’s dedicated sports and wildlife action camera a9 range, the a7 really holds its own in the speed department and the a7 III delivered 10 frames per second, which should be enough to capture everyday sports and wildlife scenarios. Interestingly, the new a7 IV keeps the speed limit at 10 frames per second, but enables photographers to shoot much longer bursts. In fact, while a7 III users could shoot at 10FPS for up to 177 JPEGs (or 40 uncompressed RAWs), the a7 IV enables photographers to shoot at 10 FPS for more than 800 JPEGs in one massive hit – just think of the action sequences you could create with that sort of feature.

Four – Focus Points:

Speed is nothing without accuracy and Sony cameras are well known for their highly advanced autofocus systems. There is a big upgrade on the a7 IV, because while the older a7 II offered 693 AF points, the newer model increases this to 756. What’s more, the a7 IV adds the Real Time Eye AF for Birds to accompany Human and Animal AF detection – further reinforcing the a7IV’s claim to be a genuine option for aspiring wildlife photographers.

Check out the new Real-time Eye AF for birds feature on the a7 IV….

Five – LCD design:

While the a7 III featured a 3-inch LCD that offered a tilting design to make awkward low/high compositions even easier, the a7 IV goes further and introduces a full-articulating design to its 3-inch LCD. This offers users even more control to position the LCD to their liking and enables the screen to be flipped around for self-portraits or when filming Vlogs. The a7 IV’s LCD is also higher resolution (1,036,800 dots v 921,600 dots). Of course, both LCDs are touch sensitive, enabling the users to establish a focus point in the frame just by touching the screen.

Six – Video: 

Although professional videographers may look to the more video-focused A7S series of cameras, there’s no doubt both the a7 III and a7IV can certainly do a great job when it comes to movie-making. The a7 III can shoot ultra high-quality video up to 4K 30p, but the a7 IV increases this to 4K 60p and this is important, because it means videographers now have the option of using this detail-rich 4K footage at half speed for a slow motion effect. What’s more, while both cameras offer Sony’s S-Log 3 colour profile, the new a7 IV also includes the S-Cinetone profile found in Sony’s range of professional cinema cameras such as the FX3. Both cameras do feature ports for headphones and an external mic so enhanced audio can be both captured and monitored.

Seven – Storage:

Okay, while storage may not be the most sizzling of specifications on the list, it is very important and should always be looked into if you are thinking of buying a camera. The good news is that both cameras feature dual SD card slots – this is useful because it enables users to make an instant backup of files, just in case anything goes wrong with one card. Alternatively, it can help keep things organised as photographers can choose to record stills to one card and video to the other. However, there is a difference here because the new a7 IV has an SD slot that can also take a CFExpress card – these cards are a little pricey, but they can record data much faster so are more suitable for recording high resolution video files.

Eight – Viewfinder:

If you prefer not to use the LCD screen to compose your images, both cameras offer the option of an excellent Electronic Viewfinder (EVF) instead. Again there’s a difference between the two models as the newer a7 IV features an upgraded EVF that, whilst the same 1.3cm size, features higher resolution (3,686,400 dots v 2,359,296 dots) that should result in a better viewing experience.

Nine – Button layout:

Sony photographers who trade up from the a7 III to the a7 IV will notice a decent amount of changes have been made to the button layout. The main adjustments to the layout see the dedicated movie record button which is found on the rear of the a7 III relocate to the top plate of the a7 IV. What’s more, the ‘half’ command dial from the a7 III is now a full command dial that sits on the top plate. In fairness, it shouldn’t take existing Sony users too long to acquaint themselves with the button layout.