We’re all very excited by the new Sony RX10 V because it’s a bridge camera with a proper-sized 1-inch sensor. Just like we’re excited by the Canon PowerShot G7 X III, the Peter Pan of compact camera designs (it was first launched in 2019). We admire 1-inch sensor cameras because they can fit in our pockets or offer huge zoom ranges in a way that larger format cameras can’t. And yet they still have these comparatively large 1-inch sensors that offer way better image quality than phones, action cameras or cheap point and shoots.
But all is not as it seems. We imagine that a 1-inch sensor measures a full inch across the diagonal, right? Not quite. Not even close, as it happens. That’s because this sensor size is a relic of a bygone era, when digital capture devices used CRT tubes and it was the size of the tube that was quoted, not the actual imaging sensor.
In fact, cameras with 1-inch sensors have a sensor measuring more like 0.68 inches across the diagonal. Indeed, you may have noticed that camera makers are now careful to describe these as 1-inch type sensors. Interesting, yes?
Sensor sizes are measured using two completely different standards. There’s the ‘old’ standard from CRT days that tends to inflate the actual sensor size, and 1-inch type sensors are the largest example, and then there’s a more modern, less… um… misleading sensor size description that actually describes the sensor size itself. This starts with the Micro Four Thirds format and carries on through APS-C, full frame and medium format.
From MFT and upwards, the sensor size quoted is actually the size of the sensor. From 1-inch type sensors and downwards, the size uses an arcane and outdated technological standard that makes sensors sound bigger than they actually are. Some kind of historical accident, right, and not deliberate at all?
There seems to be a general impression going around that cameras with a 1-inch sensor have proper-sized sensors of real quality. Parallel to this, though not connected by any direct comparisons, is the idea that Micro Four Thirds is a small and inferior sensor size. The fact is that Micro Four Thirds sensors have twice the sensor area of 1-inch type sensors.
It’s very tiresome when fads and fashions triumph over blunt facts. One of these facts is that the Sony RX10 V and Canon PowerShot G7 X III are extremely expensive for cameras with small sensors.
Yes, I’m going to call 1-inch type sensors small. If you can call Micro Four Thirds sensors small, when else would you call sensors half the size?