The Micro Four Thirds sensor format has had two big hits in the arm recently (an apt analogy in today’s times) with the arrival of the OM System Olympus OM-1 and the Panasonic Lumix GH6.

Both flagship mirrorless cameras introduce much-needed improvements to the Micro Four Thirds (M43) sensor design that, if nothing else, could at least keep naysayers quiet and allow everyone to better consider the format’s merits.

The Panasonic GH6 is primarily designed for videographers – an application the M43 sensor is ideally suited for – but the Olympus OM-1 is definitely for photographers who focus on sports, action, adventure and wildlife, i.e. the great outdoors.

I have to stress here that I’m not an M43 shooter, but I’m a big fan and have been ever since he started the whole mirrorless camera thing with the Lumix G1 and Olympus Pen E- P1. Now, as then, sensor size offers many more advantages than disadvantages, and the latest developments from OM Digital Solutions and Panasonic address a few of the latter.

The new OM-1 sensor uses a stacked design which by default is also BSI (back illuminated) so speed and sensitivity are the beneficiaries, leading to a number of significant performance benefits including wider dynamic range, lower noise levels, faster shooting speeds for stills, and faster video frame rates.

It’s likely that the GH6’s new sensor will also be a stacked design, but Panasonic is coy about exact details. However, it is unlikely that the 25% increase in resolution could not have been achieved without at least one BSI-like arrangement to free up more surface space. And it almost certainly needs a fast sensor readout in order to get continuous shooting at 75fps (albeit with AF/AE locked on the first frame).

Perhaps more importantly is Panasonic’s adoption of a dual high/low gain output – which simultaneously captures an image with less noise in shadows and increased detail in highlights and merges them on the fly – effectively overcomes the reduced dynamic range of a smaller sensor with smaller pixels. The dual gain sensors we’ve seen so far do one or the other, depending on the selected ISO, so the GH6’s Dynamic Range Boost is something new and essentially delivers an HDR image without any of the issues usual. The quoted dynamic range is 13 stops, which is full-frame sensor territory.

By the way, in electronics, gain means amplification, so with DRB there are two outputs from each pixel (by the way, analog signals at this point) – one with low amplification which avoids clipping the highlights and one with higher amplification to brighten the shadows, but without the usual increase in noise. For stills, DRB kicks in automatically at ISO 800 and above (it’s switchable when shooting video), so it will clearly benefit image quality when using high sensitivity settings .

With the new OM-1 we’ve seen the best high ISO performance of any M43 camera, and while it doesn’t close the gap to full-frame stars in low light, it does close it significantly and certainly now allows the smallest mirrorless format to easily compete with APS-C. And, for many potential users, there’s all the resolution they’ll ever need, with the Hi-Res Shooting feature becoming more and more usable and allowing for larger image files when they’re needed.

So now the benefits of the smaller sensor size can really be emphasized. Neither the OM-1 nor the GH6 are particularly small, but fit a telephoto lens – like a 100-400mm zoom, which is actually a 200-800mm – and that’s a very different story. With the major imaging performance issues effectively sorted out, the M43 now deserves a lot more attention if mobility is a priority.

Read more
Best Micro Four Thirds Cameras
Best Micro Four Thirds Lenses