Is Micro 4/3 really smaller?

4/3 sensors are a quarter of the size of 36x24mm sensors, but what about the cameras and lenses? And is it better to use a large sensor with a slower lens?

When digital photography entered the mainstream, the big question was whether or not it was good enough to replace film. The answer was obviously no, but that didn’t stop the huge surge in digital camera sales, and the rapid change that occurred in the industry.

Gilbert Rossi took this shot of Ivan Lendl with Fuji Pro 400 pushed three stops to ISO 3200. Lighting was less than ideal. Lens was a Nikkor 200/2, wide-open, on an F3. The event was the Custom Credit Australian Indoor Championships, held in October of 1984.

For years, digital sensors had no quality advantages over film, save for convenience and speed (the turnaround time, not the cameras). Colour negative film had been pushed to ISO 3200 for many years before even the first mainstream digital camera went on the market. The results were grainy but entirely usable, with good colour and contrast. As for frame rate, the Canon F-1 High Speed (1984) could shoot at 14fps, while the Nikon F3H (1998) could shoot at 13fps. Neither of those cameras were matched by a digital SLR until the Nikon D4 was released in 2012.

The Nikon F3H could shoot at 13fps. Photo: Nikoncam,

A well exposed frame of 8-perf 35mm was not as clean as a typical digital sensor, but it resolved more detail. And, of course, film had almost twice the dynamic range as the earliest sensors. These days, some emulsions still have more DR than almost any digital camera, but the lead is not what it used to be.

One of the few milestone cameras that started to really challenge the quality dominance of film was the Nikon D3. The D3 featured a 36mm sensor that had 12Mpx and offered a usable 3200 ISO, and which was not to shabby at 6400 either. Finally, there was a handheld camera that was fast in more ways than one, and had image quality that could actually challenge film.

It was still a big camera, but the D700, which followed not to long after, mostly solved that problem. The D700 was not as compact as the Olympus OM-4 or the Leica M6, especially with lenses. But many photographers decided that the compromise was worth it at the time.

A year before the D3, Leica released the M8, a rangefinder camera that had an APS-H sized sensor (1.3x crop factor compared to the traditional Leica format) that gave very good results. The Kodak sensor was a 10Mpx CCD and its files at base ISO could be printed to very large sizes. This was the first ‘mirrorless’ camera that offered a sensor that challenged film in terms of quality. It wasn’t fast in any way, but it was quite compact, even compared to the smallest DSLRs. Two out of three ain’t bad, though.

The Leica M8 was released in 2006. It is still in use today, and many photographers shoot it for the quality of its b&w files. Photo: Stephan Roletto,

And a year after the D3, Panasonic released the G1, which evolved into a hybrid stills & video camera that made possible a great many low budget movies. The G1 had no video, but it did have features which we still think of as modern: an impressive EVF, face detection, a multitude of scene modes, three aspect ratios, a flippy screen (that vloggers can’t always get on the latest cameras) and an unlimited JPEG buffer with a good SD card. In 2010 Panasonic released the G2 which included 720p video at up to 60fps.

The Panasonic G1 could not out-perform 35mm or digital SLRs, but its successors can and do. Photo: Brett Jordan,

So after all this, we have a landscape where two things happened:

  • Digital cameras surpassed film in most areas; and
  • Mirrorless (or DSLM) cameras made DSLRs completely redundant, the final nail being driven by Sony’s A9, released in 2017.

It was a long ride. In geological time this 20 year period is a mere blink of an eye. In Internet time, it’s an entire eon. But some things don’t change. An ounce is still an ounce, and an inch is still an inch. Optics is optics, and quantum efficiency is not negotiable. We know that most Micro 4/3 kits are smaller than any given DSLR kit, but here’s the trick: are they smaller than other mirrorless systems? And if so, is Micro 4/3 a logical trade-off?

Before we continue, keep in mind that we’re mainly looking at zoom lenses here. Most people find that zoom lenses are a good compromise between image quality and versatility. However, I’ll include a couple of prime lens comparisons at the end. I’m also focusing on Olympus vs Sony, as I know more about those brands than, for example, Panasonic or Fujifilm.

Handing and ergonomics are mostly subjective areas. But size and weight are things we can make judgements on in short order. But before we get serious, let’s have a look at something:

E-M5II vs A6400, both with kit lenses. These are the smallest standard zooms you can get with these cameras. However, the Olympus zoom does telescope, as does the Sony. Both lenses are mediocre but good enough for some applications. Note that the Sony here has optical stabilization, but the Olympus does not.

However, Olympus and Panasonic have the best sensor stabilization in the business, which should give the Olympus the advantage as far as hand-held long exposures are concerned. Except that in this case, the Olympus lens is probably too ambitious as far as size goes, and its image quality is not quite as good as the larger 14-42/3.5-5.6 II R. The latter tests better than the other two according to DxO. Here’s what the bigger Olympus zoom looks like:

But now the size advantage isn’t as great. You could mount the Panasonic PZ 14-42/3.5-5.6, which is as small as the Olympus 14-42 EZ. It does have OIS but to the best of my knowledge, Olympus bodies don’t apply lens corrections in JPEGs. Mounting it on a Pansonic body yields different results, depending on the model. Here are the GX85 (with IBIS) and the GH4 (no IBIS) :

But now it’s time to get serious. We’re using the Olympus E-M5 II vs the Sony A6400 as our standard bodies, as they retail for roughly the same amount. Let’s start with just the bodies.

The Sony is pretty much the same size and weight as the Olympus. There are differences but I think that they are not worth worrying about. The problem for Olympus is that the Sony body is about the same size, despite the fact that it has a sensor twice as large.

It depends on how you want to cut the cake. In some scenarios, the Sony will give you better images, due to its higher DR, which is about two stops. On the other hand, the Olympus has IBIS, which gives between three and five stops of stabilization. At worst, the E-M5 II has a one-stop advantage over the A6400 if you subtract DR (at base ISO) from the IBIS rating. But that’s only applicable if the subject is not moving.

Now let’s try this same comparison with lenses. Let’s start with the standard zoom. Preferably, the standard zoom – and the moderate tele zoom – should have a constant aperture. The lenses we’re looking at are the Olympus 12-40/2.8 and the Sony Zeiss 16-70/4 E.

What’s surprising here is that the Sony kit actually weighs less (878g vs 711g). At worst, you’d expect them to weigh the same. The 4/3 sensor is half the size of the APS-C sensor. Any lens that’s an f/2.8 lens on the 4/3 sensor can be expanded to cover the APS-C sensor at the loss of one stop. So, given that, it is surprising that the Olympus weighs more. The Olympus is weather sealed, while the Sony has OSS and is not usually revered for its optical qualities.

Going further, that same f/2.8 lens becomes an f/5.6 lens if you expand its image circle to cover a 36mm sensor, such as that in the Sony A7. But… hold that thought.

And while you’re holding that thought, let’s have a look at something else. Sony recently launched the 16-55/2.8 E, which is the first f/2.8 standard zoom made by them for the E mount system. You might think that it’s going to be somewhat larger than the Zeiss 16-70. You’d be right:

Compared to the Zeiss, the size difference is significant, as is the weight difference: 308g vs 494g. But considering that it’s an f/2.8 lens, it really isn’t that much bigger than the Olympus. Prima facie, that’s a pretty hard hit for Olympus to take, given the differences in sensor sizes. It’s worth pointing out that the 12-40 is over 100g lighter, although you wouldn’t think it. Now you know why a lot of people consider that the sweet spot is with APS-C sensor mirrorless cameras.

We’re now going to look at ultra-wide zooms. Let’s put the 7-14/2.8 Pro on the E-M5 and let’s put the 10-18/4 OSS on the A6400.

Curious. However, the Sony lens is not weather sealed, and is arguably not as good as the Olympus.

Our next test between these two cameras is between the Olympus 12-100/4 and the Sony E PZ 18-105/4:

Not only is the size difference insignificant, but the weight advantage is with the Sony. However, it’s not that simple! While both have optical stabilization, only the Olympus is weather sealed. And it is an 8x zoom whereas the Sony is a 6x. You could conclude that for the same size, Micro 4/3 gives you more. Now, you could swap the 18-105 for the 18-135/3.5-5.6, and the Sony now is not just lighter but smaller:

However, you’re getting a sliding aperture, one stop less at the long end, and a slightly narrower AOV at the wide end. Like the 18-105, the 18-135 has OSS but it is not weather sealed. Both lenses telescope, but the Olympus telescopes more than the Sony.

Now we’ll compare the Olympus 40-150/2.8 Pro with three Sony lenses, two E and one FE. The Sony lenses are, from left to right, the 70-300/4.5-5.6 G OSS FE, the 70-350/4.5-6.3 G OSS E, and the 55-210/4.5-5.6 E:

Keep in mind that the 70-300mm isn’t exactly equivalent to the 40-150mm. But it does cover the A7’s sensor, and provides a narrower AOV on the A6400. Out of the three, the 70-350 makes the least sense, as it’s not much smaller than the 70-300. All lenses except the 55-210 are weather sealed. And the 55-210’s performance is hardly stellar. All Sony lenses telescope, but the Olympus does not, due to its internal zooming. The Olympus does not have optical stabilization.

Now, let’s try and find an equivalent standard zoom for the Sony A7, the smallest camera with a 36×24 sensor. If you applied a 2x teleconverter to the 12-40/2.8, you’d get a 24-80/5.6. There’s no such lens for the Sony, but the smallest equivalent is the 28-70/3.5-5.6 OSS. It turns out that the Olympus has the advantage:

They look very similar in size, but keep in mind a few things. The Sony has a sliding aperture, and it’s two stops slower at 70mm than the Olympus is at 40mm. The Olympus has a slightly wider AOV at the wide end, and a slightly narrower AOV at the long end. I’d say it’s a victory for Micro 4/3 here. Now, let’s put the Zeiss 24-70/4 on the A7:

The Olympus is clearly more compact, but not by as much as against, say, an APS-C DSLR. A comparison between either camera and a Nikon D500 would be mildly shocking, even if you put the relatively small 18-70/3.5-4.5 G IF ED on the D500. Try a comparison with the 17-55/2.8 G IF ED and it gets ridiculous. The DSLR is a metaphorical dinosaur in more ways than one.

This comparison is going to make you think a little bit. The Leica M9, with three lenses, vs the E-M5II with the 12-40/2.8:

In the case of either the 24/3.5 or the 50/2, the M9 combination weighs slightly less. in the case of the 90/2.5, the M9 combination weighs slightly more. But overall, any one M body and any two M lenses weigh more than the Olympus. Keep in mind that each of the M 240 and the M10 weigh more than the M9.

Finally, two comparisons with prime lenses. The first compares the Olympus 25/1.8 and the Sony 35/1.8 OSS. Neither is weather sealed. The Olympus combo is smaller but heavier:

Finally, a comparison of two lenses with almost the same focal length. Olympus 45/1.8 vs Sony 50/1.8 OSS. Again, neither is weather sealed. The combinations weigh the same but the Olympus is noticeably smaller:

In general, you would be right to expect that the Micro 4/3 lenses would be smaller than they are. However, I suspect that all Micro 4/3 lenses, especially the high end ones, are designed to cover a slightly larger sensor, as seen in the GH5s. Also, keep in mind that I have not shown all possible comparisons – such as the E-M1 with a 300mm prime vs the A9 with a 600mm prime. Not that I have to, because the differences are obviously immense.

Lens scores aren’t the full story, in the same way that sensor scores are not the whole story. It’s also worth pointing out that lens scores depend on the sensor. For example, the Olympus 12-40/2.8 has a DxO score of 20 on the E-M1, but a score of 25 on the E-M1 II (that’s due to the Bayer sensor which reduces resolving power).

Some things to remember. IBIS is not a substitute for a higher shutter speed. You can take surprisingly long exposures with IBIS+OIS, but the subject is still going to move how it likes. Larger sensors are always going to be superior for single shot exposures, even though the pixel shift mode of the smaller sensor will show more detail. In fact, Panasonic’s own S1 and S1R cameras not only have larger sensors, but they also have pixel shift mode. Same for the Sony A7rIII and IV.

A final point about IBIS. Not all Micro 4/3 lenses have OIS, but IBIS is so good that you don’t really need it. When you put the two together, however, you can get very long exposures indeed. With IBIS alone, Peter Forsgard managed this exposure of 2.5 seconds:

Then there is this shot which was the result of a 10 second exposure with the E-M1 II. Yes, 10 seconds. Mind you the lens used was an ultra-wide, but still, that’s quite impressive. Robin Wong managed five seconds, as he explains in his review of the E-M1 II:

I also must be honest that, if I were standing freely, without any support, bracing myself against anything, I can only shoot at about 1 to 2 seconds shutter speed. Anything longer than 2 seconds, my legs started to wobble! Hence for the 5 seconds shots shown in this blog, I was either sitting down on the pavement (twin towers) or braced/leaned myself on a wall or something.

Robin Wong

In conclusion, Micro 4/3 isn’t always going to give you the smallest combination of body and lens. Both Olympus and Sony systems – just two out of several – are quite different and offer disparate advantages. Sony offers superior low light performance and dynamic range. Olympus allows very long handheld exposures and other features such as focus stacking. It isn’t just about size and weight.

It’s safe to say that Micro 4/3 is the system for the majority of photographers – you won’t get outright image quality but you will get a system that does almost everything, from macro to landscapes to night-time cityscapes to sport to video, liberated from gimbals and dollies. At the end of the day, Micro 4/3 is extremely flexible. And because the system is so flexible, you could excuse it for not always being the smallest.


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