Viva La Resolution! SONY A7R IV
Undoubtedly the most successful of the digital-era arrivals looking for a slice of the still camera market, Sony has not only been a serious challenger to the traditional photo brands, but looks all set to take the number one spot in interchangeable lens cameras. Canon sincerely hopes the EOS R5 and R6 will help keep the rampant Sony at bay.
Sony got off to a solid start by taking over the Konica Minolta camera business and from this sprang its first generation of DSLRs. But pretty quickly afterwards it starting doing things its own way and has never looked back. At the heart of Sony’s success is the A7 series of full-frame mirrorless cameras and the ever-expanding FE lens mount system that currently numbers 35 models, spanning 12mm to 600mm. The rapid expansion of the lens system has undoubtedly help convince buyers that Sony was in this for the long haul, as has the steady evolution of the A7 line – now in the fourth generation since it was launched back in October 2013. With 61.2MP of resolution on tap, the A7R IV makes a bold statement about Sony’s intentions… catch me if you can.
Compared to the A7R III – which has a resolution of 42.4MP – the A7R IV’s sensor represents an increase in resolution of nearly 45%, which is quite substantial and will, all other things considered, make a difference in terms of image quality. And as we are talking Sony here – the company has nailed image sensor design more comprehensively than any other (you’d be surprised how many cameras have a Sony-made sensor under the bonnet). It also knows a thing or two about processing raw data off the sensor and, in particular, creating highly effective noise-reduction algorithms.
Pumping Pixels
Not surprisingly, the sensor is a backside-illuminated (BSI) CMOS in Sony’s Exmor R series to make the most of the available space on the front surface. It has an imaging area of 23.8mm x35.7mm with a total pixel count of 62.5 million, and there’s no optical low-pass filter because you want every bit of definition that’s on offer here.
The sensor is paired with Sony’s current-generation Bionx X processor and an additional front-end LSI – a configuration already seen on other recent A series models – which delivers 16-bit image data processing, output as a 14-bit RGB RAW file. Consequently, you can have 14-bit uncompressed RAW files, 12-bit compressed RAWs and, of course, 8-bit JPEGs. Tellingly, Sony claims a dynamic range of 15 stops – pretty impressive given this is directly linked to the sensor’s signal-to-noise ratio and, in turn, pixel size. The effective pixel count of 61.2 million produces a maximum image size of 9504x6336 pixels at the 3:2 aspect ratio. For JPEG capture, there’s a choice of three image sizes, three compression levels and four aspect ratios – 3:2, 4:3, 16:9 and 1:1. The latter three are all crops, but you’re obviously still looking at very high resolutions – 54, 51 and 40 megapixels respectively. The new sensor’s sensitivity range is equivalent to ISO 100 to 32,000 with extensions down to ISO 50 and up to ISO 102,400.
The Bionz X processor is a powerhouse so, even at full resolution, you can still shoot continuously at up to 10fps with AF/AE adjustment between frames. Drop to 8fps and you can have real-time EVF framing as well
