Micro 4/3: What's in a Name?

I've had some great ideas over the years about photography—and a statistically significant number of them have come from Carl Weese.

Carl, who is currently investigating a Panasonic GX7 for us, is an artist and a working pro, a student of photography and a teacher of it, a navel-gazing artist and a social documentarian, a fastidious craftsman, even a graphic designer. (At one point he augmented his photography services by offering fully integrated graphic design services.)

Among the ideas he's tossed my way over two decades or so are the notion that B&W was already perfect in film but digital is the coming of age of color; the idea of using a digicam as a note-taker for ULF scouting; even the proper way to get to grips with the meaning and use of a Leica. He's the one who first explained to me what bokeh is.

And it's frustrating for me, now, because occasionally he'll toss off, in emails, these perfectly formed little thoughts and insights that could really be whole essays. 

Or at least whole blog posts.

Most recently, last night: Is "Micro Four-Thirds" actually a colossal naming blunder?

Why "micro"? In this day of proliferating sensor sizes, many of which really are tiny, wouldn't it cause confusion in the general public when you take an accepted but not particularly well-known or well-defined term (4/3) and add to it a word that means "exceptionally small?" Doesn't that imply, at the very least, that the sensor is smaller than regular 4/3? (Even Carl assumed so at first; so did I. Of course, it was the cameras that are supposed to be smaller, not the sensors.) Doesn't "micro" appear to intentionally underscore the difference in size of a format that is in truth just a little smaller than standard (if standard is APS-C) but difficult to distinguish from it in practice?

Fascinating. Xander told me last night about a company that tried to launch a new product with a name that very soon after became profoundly wrong. The time was just before the outbreak of the acquired immunodeficiency syndrome epidemic, the product was a weight-loss pill, and the name the inventors chose for the product was "Ayds." Oops. That's like those poor mothers who named their babies "Harry Potter" a few years before the J.K. Rowling juggernaut burst on the scene.

Carl thinks "Micro 4/3" might better have been called "Mirrorless 4/3," because it's "descriptive, not much more awkward, and wouldn't give the impression the sensor had been downsized."

Of course the common usage of "mirrorless" came along after Micro 4/3 did, I think. It was a retrospective descriptive term. But what if the official name had been, say, "SuperSensor"? Just as accurate, really, because it's supersized compared to digicam sensors...and those were, for the most part, the "mirrorless" cameras that existed before Micro 4/3 cameras along.

I'll bet that would have been a whole lot more popular with the public.

If this is a perception problem in the general public, though, it would be all but invisible to us. Core aficionados of any activity tend to sort out and demystify the terminology of their field of interest very quickly (because it's important to them) and then they just can't see any longer how that terminology might strike an ordinary person who is coming to it cold.

Maybe this a bigger part than we realize of Micro 4/3's marketing doldrums: bad name. As in, actively misleading name. As in, a name that creates rather than ameliorates confusion and poor impressions. (This could be cultural. As many people have noted, miniaturization is prized in Japan, whereas "bigger is better" is normative in the West. Interestingly, market acceptance of Micro 4/3 follows the same pattern: it's popular in Japan and Asia, struggling in North America and Europe.) Too late now, but it sure is interesting to think about...like an awful lot of the ideas I get from Carl.

Mike
(Thanks to CW)

P.S. Incidentally, a not very well-known fact: Carl teaches private one-on-one photo workshops on request. Subject: Anything you want. Most often they're about LF platinum/palladium photography, but, really, whatever you're having problems with and want to know more about, he could help you with.

Original contents copyright 2013 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.

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(To see all the comments, click on the "Comments" link below.)
Featured Comments from:

Jeremy: "Please don't suggest 'mirrorless' as a name for anything. It may be expedient in one era but it can't be lasting to call a thing by what it is not. 'Horseless carriage' (automobile) comes to mind as does 'wireless' (radio)."

Greg Brophy: "I just took a platinum printing class last weekend with Carl at The Center for Alternative Photography. My only regret was not taking it sooner. For months I tried to learn it on my own and the money I spent on failed attempts would have easily covered the cost of the class. Carl helped me learn how to do it and demystified the process. We also learned how to process negatives in a tray with pyro and showed how easy it was. I plan on taking more classes from Carl in the future.

"On aside note I got to see Carl's GX7 and it is a really amazing camera. He showed me some things I have not seen other cameras do, which I am sure he will talk about in a future post."

Comments

[Nigel]

But what if it had been called, say, "SuperSensor"?

"Super 4/3" would be my choice.

[Howard]

Mike, given all the good reports we read today pertaining to 4/3 I am one who regrets being put off by the "micro" term. I bought into another system. It was the micro designation that implied to me a very small sensor, however, my own fault in not doing my due diligence at the time.

[Fred]

I'd say half frame would be a better description since the field of view is about half for any given focal length versus a "ful frame" sensor. Yes, I realize a m43 sensor is less than half the size of FF, but all the other numbers work better and are more descriptive of the actual relationship of the lenses and fields of view when compared to the reference of FF.

[Dennis]

I think there's much more to m43 marketing problems in the US than the name. Part of it is retail presence. And part of it is the value proposition relative to entry level DSLRs. First, the average consumer looking for a "better" camera already has the preconceived notion that a Canon or Nikon camera is what you step up to from a point & shoot. Those kits start at around $500. And for that same money, in m43, you get something that looks like your point & shoot with a lens sticking out of it. *If* you're lucky enough to ever see the Panasonic 'G' series in a store, then it might be a compelling option if the price is right (and right now, at $500, the G6 is priced very well). Sony's A3000 is an attempt to compete with low end DSLRs. I understand that the EVF and LCD are both really lousy, so I don't know how well it will succeed, but at $350 in Best Buy right now (including the 18-55 kit lens) it's a ridiculously capable camera. It's cheaper than entry level DSLRs and it may offer more of what a consumer who is looking for "better than my p&s" wants.
I think the whole mirrorless market will get more interesting as more models with EVFs become available at more reasonable prices.

[MattS]

Four Thirds was a bit of an odd, opaque name to begin with. Adding "Micro" muddied the waters for the reasons mentioned in your post, and at least one more big one comes to mind:

I think the single worst thing is the confusion between Micro Four Thirds and regular, increasingly obscure, Four Thirds.

A lot of newcomers to the format seem to be unaware that there are two separate mounts involved and just drop the "Micro" in their online questions and conversations.

It's up to more knowledgable folks to set them straight. That can be a distraction, but it's not just pedantry for the sake of it, because there's a real possibility someone might wind up buying a lens or body that's incompatible with their system. (It also means people who do know the difference have to choose their words very carefully to make sure readers understand that yes, they really are interested in a piece of Four Thirds gear.)

I know of at least one real example (but there must be many) of a person buying the wrong Olympus lens because they didn't know they needed an m.Zuiko, not a Zuiko. That little "m." almost looks like a typo, doesn't it? Easy to miss if you aren't looking for it or don't know what it means.

This problem will probably get even worse as the original Four Thirds fades deeper into obscurity while much of the equipment remains available, particularly the lenses.

[Dogman]

Ayds, the appetite suppressant candy, has actually been around for decades. I remember one of my aunts going on the Ayds diet plan back in the early 1960s. I don't recall it working very well for her.

But, yes, the name "micro 4/3" is not a great marketing tool. The standard 4/3 system Olympus seems to have abandoned was really a great idea. Physically smaller but superior optics was their strong suit but Olympus kept building cameras that were no smaller than the APS-C models from other makers and customers couldn't see the point. Again, not a great marketing strategy. Still, I have great affection for the Olympus 4/3 system and their superb lenses.

[Ed]

Back in the 80s, in the UK a firm brought out an allegedly simple, anyone-can-do-it program generator called "The Last One" (as in the last program you'll ever need to buy). Before the year was out a competitor appeared called "The Next One".

[JG]

Although we'd never met, I hosted Carl for a few days while he was doing his big Drive-In Theater photo tour and I learned that he's not only very knowledgeable about all aspects of photography, but a genuinely nice guy and good company to boot!

It was an especially nice treat to view the prints he was carrying with him as well as hear his thoughtful comments about mine. (Yes, I'm afraid I made him "sing" for his supper!)

If the logistics weren't an issue -- I'm in the southwest and he's on the east coast -- I wouldn't hesitate for a minute to engage him for a private workshop or take one of his classes, as I'm certain it would be time and money well spent.

[Manuel]

As far as I know, "Micro" was chosen in order to distinguish Micro 4/3 from regular 4/3 format by focusing on the former's narrower bayonet, which was supposed to be perceived as an advantage as it allows for smaller lenses. I don't see this naming as an issue: people who started buying the Olympus E-P1 did it because it was a beautiful camera, and on the other hand the regular consumer isn't particularly aware of sensor differences (in fact most don't even know exactly what a sensor is, save for the vague notion that it is the device that replaced film). Sensor area wars are left to a comparatively small number of enthusiasts, who are well aware that it is a 4/3 sensor that lurks inside Micro 4/3 cameras.
I'd say it isn't that infamous "Micro" moniker that's hurting the format's sales: it's all the bad press it gets nowadays due to the growing demand for larger sensors. Those foolish debates about "aperture equivalence" on internet forums don't help Micro 4/3's cause, and neither do those outlandish claims made by companies like Mentalbones about devices that purportedly increase aperture. As a result, folks now believe it is impossible to get 'bokeh' with small sensors and dismiss Micro 4/3 on the account of its small sensor area. (At least that's the impression I get when I peruse DPR's comments section, but I could be wrong.) I agree it is silly, as the dominant APS-C isn't much larger than 4/3, but silliness accounts for much in photography's current state of affairs.
As for me, having owned an Olympus E-P1 four three years, the real issue I find with Micro 4/3 is dynamic range. Older 12,3 MP sensors clip highlights all too easily. More recent Sony-manufactured sensors seem to perform better, but there's no denying all digital cameras (with the possible exception of medium format) tend to blow highlights. Of course, full frame behaves better in this respect, so I believe the push for larger sensors is a step in the right direction.
Does all this mean Micro 4/3 is doomed? Dunno. If it is, it surely has little to do with bad naming...

[Ed Hawco]

@Jeremy, in this case "Mirrorless" is to differentiate it from "regular" four-thirds, which was designed to be used with a mirror box (distance from mount to sensor). The only real difference with MFT is that distance is reduced as there is no mirror box, so in this case it fits.

It also means there's no need to need to change the abbreviation (MFT), which is, I think, in wider use than the full spelled out version. As "mirrorless" ages, more and more people will just use the abbreviation.

And then there's the annoying "µFT," which should be banned outright.

[kirk]

Off hand, I couldn't think of a worse name for a camera format. The format is the same basic size as "Super 35" in the movie world. What a great name that is for a format!

[Luke]

Full-frame is the standard 100% size, so that's 3/3. So, 4/3 is even bigger! No? And Micro 4/3 is.... the same size?

But now we finally have the first true Micro 4/3 camera, the GM1. It's the heart of the GX7 in a much smaller package, like we expected from Micro 4/3 from the beginning.

[Jayson Merryfield]

Conversation with my wife, who was looking at the E-M1 and 17 1.8 I recently acquired.

“I thought you said you were upgrading your camera.”
“I did. This is the upgrade.”
“It’s BETTER than your big camera?” (Note: Olympus E-5)
“Yep.”
“But it’s so little!”
“That’s sort of the point.”
“I don’t think people will take you seriously when you pull out this little thing.”
“Oh well.”

Side note: I would be all in favor of dropping the Micro appendage and returning to plain ol' Four Thirds. Really though, the current situation with M43 is kind of unprecedented in the consumer market: two major camera manufacturers both building cameras and lenses that are completely interchangeable. How many people assume that, as with Canon, Nikon, et al, that only Panasonic lenses work with Panasonic cameras, and Olympus only works with Olympus?

[John Krumm]

I don't think the name is the whole problem, though it might be a part of it. What I see is a lack of penetration into areas where regular consumers can see the cameras. Costco is still a line-up of dslr's and point and shoots, with Nikon's V cameras the exception. You have to remember that the big mirrorless manufacturers are the minor brands, and they would also sell low volumes if they made dslrs. Pentax/Ricoh isn't exactly selling tons of its traditional dslrs, nor did Oly and Panasonic a few years back. If Canon made an aps-c mirrorless camera as good as the EM1 you would see it everywhere, and it would sell like crazy I bet.

[BH]

I am not sure if it matters. Almost nobody knows what 4/3 was to begin with, except folks like readers here who have, as you put it, sorted out and demystified the terminology.

Perhaps the bigger reason m4/3 bodies aren't flying off the shelves is that they're not ON the shelves. Target, Wal-Mart, Best Buy and every other box store you walk into has a bunch of entry level Canon & Nikon DSLR's, followed by a wide array of superzooms and point and shoots that immediately fade into memory as a mass of plastic and buttons.

If you're not already indoctrinated into the world of camera gear, you're either a smartphone shooter or someone who wants more. The person who wants more has one thought, "I should get myself one of those Canon/Nikon DSLR's". I think this consumer behavior is something that would be extremely difficult for a company like Panasonic or Olympus to upset. Micro 4/3 is a pretty cool sounding name. What they really need is a better marketing team.

[dave rogers]

I would say that for the kinds of customers Olympus is trying to reach with the m43 format to grow the market, the name is really meaningless. Which is not to say it couldn’t be better, just that “micro” isn’t a pejorative to those customers. Indeed, it’s perhaps more the ideal they’re looking for.

Olympus has been on record saying they were trying to attract more women to their brand. The smaller size is more accomodating and less “camera-nerdy” than the large black DSLRs with enormous zooms some people carry. It allows them to use interchangeable lenses without all the (literal) baggage burdening many DSLR owners.

While m43 cameras are very small compared to most of the DSLRs we’re accustomed to, they’re still quite large compared to a point-and-shoot you could keep in a purse. Anything that reinforces the notion that it’s “small” is perhaps desirable from a marketing standpoint.

But yeah, the guys (and they’re almost always guys), are going to regard the “micro” as a pejorative. Some have gone so far as to write in a forum I won’t mention that if it doesn’t have an optical viewfinder, you might as well use your cell phone. This from a guy who shoots the same sensor format, just a different lens mount, disappointed there was no E-7 forthcoming from Oly.

Size matters. Just in different ways to different customers.

[RIck]

Jeremy's featured comment struck me as very curious. My first thought was... "wireless" doesn't work?? That happens to be the dominant name used for the entire mobile phone industry in the US. Just look at the the names of the major carriers here.

Mirrorless just might have worked after all. I certainly never understood the choice of "micro" by the industry, although your explanation that it was a cultural Japanese influence seems very plausible.

[David Dyer-Bennet]

Should have called them "Electronic Viewfinder Interchangeable Lens" cameras.

The M43 companies were caught in the problem of having an existing Four Thirds market they were probably far too worried about -- if that market had been healthy they wouldn't have needed M43. But companies are almost always too concerned about their current business when looking at future directions.

[Clay Dawson]

With or without the Micro or Mirrorless, it’s a terrible thing to call a camera because no one can figure out what it’s 4/3rds of.

[Keith B]

As a visit to the Wiki will tell you, the AYDS trademark was registered in 1946. I remember the radio and TV commercials in the 1960's and 1970's.

[Adrian Mills]

I have been thinking about a go everywhere camera as a DSLR backup. I hadn't dismissed a micro 4/3 I just hadn't even considered one. I guess I had automatically and not even really consciously assumed that the sensor was small. I shall reconsider!

[Howard Sandler]

Perhaps it's not too late to change the "official" acronym MFT to mean "Mirrorless Four Thirds". A historical example is the GSM personal communication radio standard. When it began as a Europe-only digital cellular system, GSM stood for "Groupe Spéciale Mobile", the French term for the standards group. Only later, when the system was adopted in many other countries, including Canada and the US, was the acronym re-defined to mean "Global System for Mobility".

[G Dan Mitchell]

"Core aficionados of any activity tend to sort out and demystify the terminology of their field of interest very quickly..."

Maybe. On the other hand, certain terminologies are used to avoid dealing with the reality of the thing, and there a plenty of examples of that among photographers and photography enthusiasts.

[Kenneth Wajda]

Wearing my bibless overalls, I'm loading my new mirrorless camera in my horseless carriage. Fortunelessly, now my wallet is moneyless.

(Actually not true, I'm still shooting with your GF1, Mike, with a 20mm f1.7 and a thumbs up! It rocks!)

[Mahn England]

To my mind the term "Micro Four Thirds" is just as obscure and extrinsic as "Digital Single Lens Reflex" is. Its significance as a literal descriptor diminishes with time and as the technology that caused the term to be coined as a differentiator becomes redundant.

[Alfonso Rubio]

Mirrorless is sooo old. In a few years people will have forgotten about what did a mirror inside a camera.

Micro four thirds is an accepted and recognized name, and if it is recognized it triggers an association in your brain, which is the basis for comunication. I vote for micro 4/3.

[Arg]

µ4/3 is not a name of any camera. In Australia, the Olympus website and the Panasonic website do not mention the phrase "micro four thirds". So how is it a naming blunder?

The American market shows their buyers care a lot more about a name than they should. A lot more than many other markets do. According to you, they even care about a name that isn't used for any products!

The real reason it isn't picking up in the USA is because the Big Two are not seriously doing it.

[David Brown]

"Among the ideas he's tossed my way over two decades or so are the notion that B&W was already perfect in film but digital is the coming of age of color ..."

Slightly off topic, but ain't that the truth!

[george4908]

I've had the reaction from several non-camera geeks that my OM-D was cool looking but, being small, they assumed it wasn't quite a serious picture taking instrument. When I explain that large flapping mirrors are an antiquated 50+ year old technology (heh heh), and that this camera represents the current state of the art, from which a smaller and less clunky footprint naturally follows, they come around pretty quickly. I suspect that if the boys in marketing worked this angle properly, they'd make a few more converts. But as several people here have already said, the near invisibility of Olympus and Panasonic cameras in retail stores is real disadvantage no matter how they're named.

[Ash]

Good article!

At this point it would be wise for them to shy away from promoting 'micro four thirds' Let it devolve into an icon and small print on the boxes.

The best known brand names they have available are Olympus and Panasonic, and these are the names that should be marketed to the public.

They should let 'zuiko', 'lumix' and 'm4/3' all fall by the wayside, and spend their marketing dollars where they can reach the largest number of camera buyers.

[Mike Anderson]

Regarding names, I've heard the acronym MILC being used these days to refer to the growing category of Mirrorless Interchangeable Lens Cameras. This is generally assumed to be a digital camera, but Leicas and other old film rangefinders with interchangeable lenses are technically MILCs.

[Bob Dales]

What does "mirrorless" mean to a typical point and shooter? Does an aspiring upgrader know that a DSLR contains a mirror? That a point and shoot or a super zoom or smart phone camera doesn't? And a mirrorless is something else? And how about Sony's semi-mirror DSLRs?
The only thing worse is the sensor size nomenclature.
I think only 3 terms have standing.. Canon, Nikon, Sony. The rest is noise.
Happy not to be a camera marketer.
bd

[Martin Doonan]

As a few commenters have mentioned, I think the market share thing boils down to 3 things: availability, price, size.
In Asia (and NZ on a recent trip), I see micro-4/3 reaasonably well available - in Europe (and I guess US) hardly visible at all.
However, in those wider markets, Nikon & Canon are crushing the competition with the cheap entry-level DSLRs.
Size becomes a bit of an issue - Asians tend to have smaller hands, and seem to prefer smaller devices (not just cameras). DSLRs are generally larger and I know a few who find them difficult to hold.

As to all those issues about image quality, controls, focus, aperture etc etc, quite frankly the ordinary man in the street does not know nor care one jot about them. These are the realm of the relatively small group of enthusiasts who populate sites like TP and DPReview.

[Kurt Friis Hansen]

Is that really all we have to worry about? A name?

We all know, that the camera industry is threatened by mobile phones. It may even be the truth, but I recently got the feeling, that there is much more going on.

...I still need an explanation to, why so many people use large iPads as cameras. A month ago I saw several (more than half a dozen) in use for photographing performers in a night club in Mexico City. With iPads in size akin to many "technical" camera backs. And weighing in at almost the same.

This is not a case of "the camera you have at hand", but the "camera", you decide to take with you. And it is much, much larger and has a much more limited quality than even cheap compact consumer cameras. How come?

If small compacts like i.e. Panasonic LF1, Canon S120 etc. cannot even compete with iPads weighing in at 1,5 pounds or more "fully dressed" for outside use, there's something else going one. What's going on here?

Nobody has yet explained, what possesses i.e. petite ladies shooting snapshots in low light with these heavy and LAAARGE iPads. They do. In droves, so... Some of them even had iPhones lying beside the drinks on the table. What's happening?

Compared to that intriquing fact, the "what's in a (daft) name" discussion seems utterly use- and pointless.

There must be much more to the current "shift" in the camera industry, than just mobile phones (although they're convenient in some cases).

Now, there's an issue, that warrants some investigation. In my view.

[Richard]

As mentioned Ayds was a "candy" not a pill. Little chocolate squares actually. My mother kept a box in the early 70's in the back of the fridge.

[Andrea]

Forgetting the name for a second, what's the deal with the logo? Is there a saw mounted somewhere I did not yet find?

Bad jokes aside, I never heard any "regular" person mention APS-C, FF or M43, so I guess the name is not that important. What is important is getting quality pictures in the smallest yet practical format, and I think M43 is a good compromise, as a lot of "irregulars" seem to do. This notion will, eventually, cascade down to the "regular" Joe. In the meantime, I am eagerly expecting Carl's next instalment. That GX7 looks like something, doesn't it?

[Dan]

Another problem that the m43 gang faces is all of the "more or less compatible" gear out there. I'm using E-M1 and E-M5 bodies and several lenses (waiting for my lovely 12-40 f2.8), because they're a great fit for what I do, which is landscape, but often on very long multi-day, sometimes multi-week hikes where a big ol' DSLR would choke me and anything without weather seals would be trashed. Even as a relatively technical person, I have some trouble figuring out what works with what... Olympus bodies are fine with Panasonic lenses, because both are stabilized - use the Olympus body stabilization if it's an OM-D, but the lens stabilizer is better on any lesser camera (well, I only own OM-Ds right now, so that's at least a bit easier). Panasonic bodies with Olympus lenses work, but they have no image stabilization, because both expect the other to be stabilized. Oh, and most Panasonic lenses are great on Olympus bodies, but not that really attractive 7-14 - THAT lens has ugly purple flare (but it doesn't on Panasonic bodies). A bit confusing, no?

That said, the OM-Ds are a great pair of bodies - smaller than a Rebel, sealed like a D4, and the E-M1 has fantastic controls and the nicest electronic viewfinder around! The best lenses are also terrific, and the overall image quality is more than competitive with anything but a full frame camera, and only lags those at high ISO or huge print sizes.

Dan

[ggl]

The silly name didn't stop Microsoft software giant from becoming a world monopoly.

When I first saw m4/3, I quickly became interested. Shorter flange, but the sensor is the same size as 4/3? That would allow for smaller lenses and less complicated "wide"-angles. m4/3 was the first system to deliver the failed promise of 4/3: a smaller and lighter cameras-lens system with decent image quality. So in the sense the name is quite accurate. Olympus' strength has always been miniaturization.

[s.low]

Micro 4/3? Micro Four-Thirds? M43? MFT?

Micro FourThirds is the name in the logotype and it suggests tiny tools with a four by three image ratio. An honest name.
'Micro' is of course somewhat confusing, since this word is also a synonym for close up.
But isn't it a better description than APS-C or DSLR? What does the average consumer get from 'Digital Single Lens Reflex' anyway?
That it is not a Digital Twin Lens Reflex?
And 'mirrorless' sounds like a marketing mistake. Why pay for something that is not there?

The photographic industry has a bad reputation when it comes to naming formats. For example: 6x6 and 6x7 are smaller than 4x5.
And when Oskar Barnack designed his 'Kleinbildkamera' in 1924, Anglo Saxon countries called this 24x35mm format 35mm. We know where that comes from but it is a silly name for selling cameras.

'Small' is not a popular verb in the US. When we visit the US my wife and I sometimes are desperate for a decent cappuccino. Then we go to Starbucks and order one cup of the smallest size available: 350ml. More than enough for the two of us. This smallest size is called 'tall!'

It is all about culture. Supersize me, my wife, my kids, my home, my car, my coffee and my camera.

The format is succesful in Japan and other Asian countries. Does anyone know if the format is there also described as Micro FourThirds? In English?.

[David Bennett]

I don't think the name is a problem except that it is ungainly. In time it will be reduced and abbreviated - probably to Goldilocks.

[Roger Engle]

Since 4/3 is a sensor standard, and MFT simply changes the mount standard to something smaller, why not call it 3/4 4/3? No? MFT works fine for me.

[Kevin Purcell]

Micro Four Thirds logo appears on all all products made by companies that are part of the Micro Four Thirds Consortium and that conform to the Micro Four Thirds specification.

The idea for the customer is that they see the logo on camera bodies and on lenses and knows that they will work together. It's not a trademark to sell the camera format. That way never the intention.

http://www.four-thirds.org/en/microft/whitepaper.html

"Four Thirds" as a trademark was the result of engineering pun.

The sensor diameter (diagonal of 21.63mm) is "Type 4/3 inch" in "vidicon tube size" parlance. And the sensors have 4:3 aspect ratio. Geddit?

One probably shouldn't let engineers have input on marketing names.

http://web.archive.org/web/20110714235957/http://www.olympus-europa.com/consumer/dslr_7045.htm">http://www.olympus-europa.com/consumer/dslr_7045.htm">http://web.archive.org/web/20110714235957/http://www.olympus-europa.com/consumer/dslr_7045.htm

FWIW, only the image circle diameter is specified in Micro Four Thirds specifications but the spec guarantees that lenses will not vignette with aspect ratios of 4:3, 3:2 and 16:9 on a 21.63mm image circle.

"Quarter Frame" would be an accurate description though perhaps not a good marketing term.