The Sony Alpha 7R IV breaks the 50MP barrier, but how else does it improve on the sensational Alpha 7R III? Michael Topham investigates
Sony Alpha 7R IV Review: Image quality
The A7R IV’s new sensor has got a lot of photographers excited about what we can expect from the next wave of high-resolution full frame cameras. As we’d predicted, the lab results from the Sony A7R IV are the best we’ve ever recorded from a high-resolution full-frame chip.
Its 9504×6336-pixel count equates to a 31.6×21.1in or 80.4×53.6cm print at a critically sharp 300ppi output resolution. Even when you crop down to APS-C mode, you can still capture 6240 x 4160 pixel files that measure 20.8×13.8in (52.8×35.2cm). The APS-C crop mode will be appreciated by animal photographers who typically rely on cropping after capturing images of quickly moving animals/birds afar.
Sony Alpha 7R IV Review: Resolution
Looking at raw files processed using Adobe Camera Raw, its evident that the A7R IV captures mesmerising detail from its 61.0MP sensor, which forgoes an optical low-pass filter (OPLF). At ISO 100 the sensor achieves approximately 5,400lines per picture height, which exceeds all figures we’ve previously recorded by other high-resolution full-frame mirrorless cameras. Resolution gradually drops off as the ISO is increased, with 5,000l/ph being measured at ISO 800 and 4,600l/ph at ISO 6400. As to be expected, the level of detail beyond this point does start to reduce as the influence of noise becomes more prominent. That being said, it still manages a staggering result of 4,400l/ph at ISO 12,800 and 4,000l/ph at ISO 51,200.
From the crops below, multiply the number below the lines by 400 to calculate the resolution on lines per picture height. These were shot with an E-mount version of the Sigma 85mm F1.4 DG HSM Art.
Sony Alpha 7R IV Review: Noise
The high ISO performance of Sony’s high-resolution sensors these last few years has been astonishing and the A7R IV continues this trend. Opening raw files in Adobe Camera Raw and examining them at 100% tells us clean, noise-free images are produced between ISO 100 and ISO 1600. Noise starts to creep in at ISO 3200 and ISO 6400, but it’s so negligible and inoffensive it won’t stop you using these settings. I found that acceptable results can be achieved at ISO 12,800 and ISO 25,600 too, however you will find yourself wanting to apply a little noise reduction during post processing. Colour remains well saturated and punchy between ISO 50 and ISO 12,800, with a hint of a green tinge creeping in at ISO 25,600 and above. The upper ISO 51,200 and ISO 104,200 settings might sound good to have, but you’ll want to give these a wide berth as the image quality really starts to visibly degrade.