Sony A7R IV Underwater Review

Sony is known for being an innovator. And the truth is….they deserve it. The release of the Sony A7R IV is a testament to this fact. The A7R IV is no minor upgrade and it puts Sony at the top of the mirrorless camera market and potentially as one of the best underwater cameras available. And if you thought the Sony A7R III was already a top camera, well the A7R IV is almost 20 megapixels more advanced. The A7R IV features a 61 megapixel full-frame Exmor R CMOS sensor – the most megapixels of any mirrorless camera to date. And the specs don’t stop there. Despite huge file sizes, the A7R IV can still accomplish 10fps continuous shooting (7 second buffer), real-time AF tracking in video, and a Pixel Shift Multi Shooting mode that can create 240 megapixel photographs. For those photographers that might be put off by the rediculous number of pixels – the A7R IV appears to be a fairly versatile camera with plenty of capability for day-to-day underwater shooting. This isn’t a camera that was just made for specifications. This was a camera made to be a photographer’s workhorse.

We think the Sony A7R IV is the mirrorless camera of the future, and certainly a top choice for underwater photographers. Now that underwater photographers will have access to so much resolution, we can’t wait to see the caliber of art produced in the next few years. Macro photographers will especially be able to crop to their hearts desire! The well-roundedness of this camera makes it perfect for macro, wide angle, supermacro, pelagic shooting, and pretty much any other type of underwater photography you can think of.

Our team at Bluewater Photo was fortunate enough to receive a prototype Ikelite A7R IV housing to use with our new Sony A7R IV camera. We decided to take the set up on our trip aboard the Socorro Vortex - a new liveaboard running luxury trips to Guadalupe Island, Mexico - to go cage diving with great white sharks. After some spectacular underwater moments, we can safely say that the A7R IV is the camera of the year!

U.S. MSRP Sony A7R IV: $3500

Available Now!

One of the world's first underwater photos with the Sony A7R IV. Taken with the Ikelite A7R IV housing, dual Ikelite DS 161 strobes, and the Sony 16-35mm rectilinear wide lens aboard the Socorro Vortex liveaboard. 1/250, f/10, ISO 320

Comparison | Specifications | Features

Underwater Photo and Video | Lens Recommendation | Underwater Housings |

Sample Images | Final Thoughts

Sony A7R IV vs Sony A7R III

The Sony A7R III has is still one of the top cameras on the market for underwater photography. R means resolution. So of course the main upgrade to the A7R IV is a new 61 MP sensor from the A7R III’s 42.4 MP sensor. Sony is claiming that the A7R IV will maintain the same 15 stops of dynamic range at low ISOs that was available on the A7R III, and the ISO range is the same. We found that this was generally true in our underwater tests. Another nice feature, though not for underwater photography, is that the pixel shift feature has been updated to create 240 MP photos. Autofocus has improved on the A7R IV, which will be welcomed by underwater photographers. The A7R IV has almost 200 more phase detection focal points, covering 74% of the width and 99% of the height of the sensor’s surface. Both cameras still have a low light sensitivity of -3EV (@f/2). The AF system has been updated and includes touch tracking AF like on the a6400, as well as Eye AF in movie recording mode. When we took the A7R IV underwater, we could confirm that the autofocus system is lightyear's ahead of the A7R III! The EVF (electronic viewfinder) has been updated with higher resolution to 5.7M dots. So overall, I think it’s safe to say that the Sony A7R IV is an all-around better camera than the A7R III with an emphasis on resolution.

Sony A7R IV Camera Specifications

Key Upgrades from the A7R III

• 61 megapixel full frame Exmor R BSI CMOS Sensor vs 42.4 MP sensor in the A7R III

• Updated BONZX Image Processor

• Updated pixel shift feature can now combine 16 still photos to produce a 240 MP photo

• Improved autofocus capability – phase detection point coverage, and updated AF sytem including touch AF tracking and Eye AF in movie mode

• Eye Animal AF Tracking

• Updated EVF – now 5.7 M dots

• New Multi Interface Shoe (MI Shoe) – designed for audio

A tiny blenny stands out with detail that only a 61 megapixel camera could capture. Taken with the Sony A7R IV, Ikelite A7R IV housing, dual Ikelite DS 161 strobes, the Sony 90mm macro lens, and the Bluewater +7 diopter. 1/250, f/11, ISO 200

Sony A7R IV Complete Specs

• 61.0 MP Exmor R CMOS Sensor

• BIONZX Image processor

• 567 phase detection AF points, 425 contract detection AF points

• Phase detection AF points cover 99% of the height of the sensor and 74% of the width

• Autofocus tracking system updated with touch tacking AF and Eye AF in movie mode

• New Eye Animal AF Tracking!

• -3 EV lowlight AF sensitivity (w/ f/2 lens @ ISO 100)

• ISO sensitivity of 100-32000

• 15 stops of dynamic range at low ISO

• 4K video @ 30P

• S-Log2/3 and Hybrid Log Gamma picture profiles supported for video

• 3.0 inch LCD with 1.4 M dots – adjustable with 107 degrees up and 41 degrees down

• Zebra stripes and peaking MF available

• 1/250s flash sync speed

• Electronic shutter for silent shooting

• 5-axis in-body image-stabilization

• Continuous shooting Hi+: 10fps, Hi: 8fps

• Compressed RAW buffer of 68 frames, uncompressed RAW buffer of 30 frames

• 530 shot battery life

• Dual card slots – UHS-II

• Bluetooth and WiFi capability for image transfer

• Size: 5 1/8” X 3 7/8” X 2 3/4 “

• Weight: 1lb 7.5 oz/665 g

Sony A7R IV Key Features

Body, Build, and Ergonomics

The Sony A7R IV is a solid camera and with slightly improved ergonomics from the A7R III. The handgrip has been redesigned and made deeper. For the most part, the controls are unchanged from the A7R III so any Sony photographers looking to upgrade won't have to adjust their shooting style all that much.

The biggest improvement in ergonomics for underwater photographers is the electronic viewfinder. It maintains its size and 0.78X magnification rating, but it has a higher resolution at 5.76 million dots. And for underwater photographers that operate in extreme environments, often with low visibility, the more resolution the better. Battery life is the same as in the A7R III with about 530 images per charge. This is quite a bit better than competing full-frame mirrorless systems. Because of the size of the uncompressed RAW files, we actually found out that we ran out of space on our cards before running out of battery! The battery on the A7R IV is about good for four dives of hard shooting - which is plenty if you ask us!

If you’re picky about dual card slots, well you're in luck – two UHS-II slots. With such high resolution, you're going to need them.

Resolution and Image Quality

The Sony A7R IV’s 61 megapixels is an astounding upgrade from the A7R III’s already substantial 42.4 MP. 61 MP is enough resolution to crop anything you want and still have an amazing quality photo. This is a serious improvement for macro photographers. However, the size of the files you end up working with is something to consider - you're going to need a good computer to process your files and a lot of storage space. In three days of photographing sharks heavily we managed to fill up about 500 gb of space. It's definitely somthing to think about!

We found that sometimes it was hard to notice the benefits of increased resolution on moving subjects. Because there are so many megapixels on this sensor, it's important to shoot at higher shutter speeds. Improved detail is going to be more apparent on still subjects. Because motion blur increases at higher resolution, we found that our macro photographs benefited most from the A7R IV. Although our photos of great white sharks had extremely high resolution, they lost some detail due to motion blur. Our macro photos produced higher quality 100% crops than our wide angle images.

The engineers at Sony did a great job in maintaining the same great ISO sensitivity, dynamic range performance, and low light autofocus sensitivity as was available in the A7R III. Higher resolution sensors ten to take photos with a little more noise, even at lower ISOs. Fortunately, you can remove noise easily in post processing because the grain is very fine. Overall, we found the image quality to be better than the Sony A7R III, Nikon D850 , and Nikon Z7 – the A7R IV’s main competitors. This was particularly true in photos where the frame is frozen and without motion blur.

Beautiful image quality and dynamic range produced by the Sony A7R IV. Taken with the Ikelite A7R IV housing, dual Ikelite DS 161 strobes, and Canon 8-15mm fisheye lens w/ metabones in Loreto, Mexico. 1/160, f/18, ISO 200

Sony A7R IV 100% Crop Test

The only way to truly understand the value of 61 megapixels of resolution is to "pixel peep." With other cameras, pixel peeping can make you feel like you have a bad camera. But with the A7R IV, it brings out details that could not be captured with any other full frame camera. Macro photographers, in particular, can really benefit from 61 megapixels of resolution. Cropping lets you "recompose" your photo in post processing as well as bring out details beyond what your camera could capture with normal composition. Sometimes cropping is the only way to create a photo of an extremely small subject. Here are some 100% crops of macro photographs captured with the A7R IV, that show just how truly amazing 61 megapixels is. Be sure to click on each photo to view them in a larger size.

Autofocus System

Sony is known industry-leading autofocus capability. The Sony A7R IV has all of Sony’s updated autofocus technology which is nothing short of spectacular. We found that the A7R IV's autofocus system is far superior to that of the A7R III during our underwater tests. In fact, having this improved AF system is almost a more compelling selling point than the resolution update. When we shot great white sharks in the cage, the AF tracking system locked on focus every time and stayed wit hthe shark. We never had to worry that the focus point would lock on to anything else and all our efforts could be shifted to compostiion. When shooting in burst modes, some frames didn't keep up with quick movements, but it's clear that the AF system is one of the best on the market.

I often prefer to shoot in single AF, especially when shooting macro photos. However, the continuous AF system was so accurate that I was ok with letting the camera keep track of the AF point while I composed the shot instead of my usual "lock and pan" in single AF. Being able to trust the AF system is a big deal for an underwater photography as it frees up attention for focus on other, more important, aspects of photography.

Nudibranchs may be slow but quick autofocus is a huge help when the current is high. Taken with the Sony A7R IV, Ikelite A7R IV housing, dual Ikelite DS 161 strobes, the Sony 90mm macro lens, and the Bluewater +7 diopter. 1/250, f/14, ISO 200

Sony’s AF tracking system is one of the quickest AF systems in the world topside. The A7R IV is being used to also introduce Eye AF in movie mode and touch tracking AF – both won’t have much use in underwater photography.

Autofocus sensitivity in lowlight is still -3 EV (w/ f/2 lens @ ISO 100). This is pretty great considering the upgrade in megapixels. Although the lowlight AF performance could be improved a bit, it is certainly in line with the Nikon D850, Nikon Z7, or Canon EOS R - and better than the A7R III.

A quick and intelligent AF system is perfrect for capturing quick subjects. Taken with the Ikelite A7R IV housing, dual Ikelite DS 161 strobes, and Canon 8-15mm fisheye lens w/ metabones adaptor aboard the Socorro Vortex liveaboard. 1/125, f/7.1, ISO 100

Video Capability

The video capability of the Sony A7R IV is about as good as it was on the A7R III – which is excellent. Sony has added an Eye AF feature, but that isn’t useful for underwater video. The A7R IV can shoot 4K @ 30p with S-Log2/3, and hybrid log gamma picture profiles available. The 4K quality is excellent on the A7R IV as it is downsampled from 6K – increasing the amount of detail in the image. Given these stats and the video quality, we expect underwater video shooters to be choosing between the Nikon Z6, Sony A7R III, and Sony A7R IV – at least until the Sony A7S III comes out.

Our initial sample video includes footage taken during our shark dives with the camera off the coast of Guadalupe Island, Mexico. It is slightly compressed to to the lack of processing resources we have in the field, and we cant wait to come out with a full video soon!