Micro Four-Thirds and Telecentricity

When you go away on a vacation and deliberately stay out of touch with what's going on, you half expect the world to have changed by the time you get back—and sometimes it's nice when it really does. (Sometimes it's not nice at all: war between Russia and Georgia? I didn't see that coming.) 

What I mean, of course, is the really encouraging news from Olympus and Panasonic about the new Micro Four Thirds standard. My initial reaction is tempered somewhat by the fact that we haven't seen anything about implementation yet, and implementation with digital devices is crucial. But still, it's exciting.

Some of the Olympus materials about Micro Four-Thirds talk about market share, saturation, opportunity, and so forth, and, doubtless, part of what the two companies are doing is trying to wedge open a new niche with the potential to become a big category. In trying to meld together a point-and-shoot body size with the lens interchangeability and image quality of a DSLR, however, one big question is whether they'd rather the result be more like the one or more like the other. Naturally, what comes dancing in front of my eyes when I read about Micro Four-Thirds are exquisitely constructed deluxe little metal gems like miniaturized Leicas, tough and waterproof and with image stabilization and top-quality lenses, and responsiveness as sharp as a razor; but what might be dancing in front of the designers' eyes could be something completely different—like millions of consumers with full wallets who just want slightly better point-and-shoots. Again, implementation is crucial. But when the products are announced, I hope there will be both consumer and "professional" (premium) options right from the start.

Telecentricity requirement relaxed?
One thing that seems probable is that the Micro Four-Thirds lenses will be very small. Jonathan Guilbault writes to tell me that backpackinglight.com has a very interesting article about Micro Four-Thirds by Rick Dreher, based on original interviews with Olympus reps at Outdoor Retailer Summer Market 2008. Unfortunately the article is only available to paid subscribers to the site (you can buy a single article, but only to be mailed to you in hard copy form). However, Jonathan tells me that the article reports that, as part of the new standard, Olympus and Panasonic have decided to relax the strict 100% telecentricity requirement of the full Four-Thirds standard. As you probably know, this part of the standard requires that image-forming light must impinge on the sensor at a perpendicular angle; it's a primary reason why the superb 4/3rds lenses are mostly as large as 35mm lenses (long telephotos excepted). Here's a brief quote from the backpackinglight.com article:

Of great importance, if not well understood, is the relaxation of Four-Thirds' rigid telecentric lens standard. CCD imaging chips used in early digicams need light to hit the chip surface at a perpendicular angle, as their photosites sit in depressions that off-angle light can't reach evenly. This creates havoc that the original Four-Thirds standard addressed by demanding system lenses be perpendicular (telecentric). However, newer NMOS chips new used by Olympus and Panasonic don't suffer fatally from angled light, and advanced in-camera processing can address intensity differences that still occur across the frame.

This allows the Micro Four-Thirds rear lens element to sit closer to the chip which, in turn, allows lenses to be smaller. Thus unleashed, camera and lens designers can now employ classic wide angle lens designs unusable in SLRs, create zooms with rear elements that protrude into the camera body, and shrink many lens parts.

I don't know why this wouldn't be mentioned in the official inaugural publicity about the new Micro Four-Thirds standard. But if it's true, it will be at least as important as the greatly reduced flange distance in allowing dedicated Micro Four-Thirds lenses to be significantly smaller and lighter than 35mm, APS-C, and existing 4/3rds lenses, without sacrificing optical quality.

Wait and watch
How significant is Micro Four-Thirds? Well, I don't know, of course, and I think it's dangerous to guess at this point. I think that potentially it could up-end the entire camera market—which could look very different a year from now as a result. But that one-word qualifier ("potentially") is still important. As robust as it is, the digital-imaging-device  market is still subject to extraordinarily complex volatility. Deeper analysis is probably pointless until we see actual products.

I can tell you one thing for certain. I'll be waiting to see what Olympus and Panasonic have cooking before I buy anything new. After pining in public for several years now for just the sort of camera that one of these could turn out to be, it seems the least I should do.

______________________

Mike  (Thanks to Jonathan)

Comments

[latent_image]

Mike, I've been reading a lot of the speculation about what sort of MFT cameras we might see and might like to see. In terms of what the designers and marketers might be aiming for, I think the critical fact is this is a mount for interchangeable lenses. Whatever comes, the direction doesn't seem to be towards point-and-shoots. Point-and-shooters don't want the hassle of carrying lenses and changing lenses.

[Bob Dales]

Welcome back Mike. Hope you have some keeper fish pix.
Maybe we should all email the Micro Four-Thirds spec to the camera guys at Sigma. Don't worry about their lens bretheren, they get it.
This announcement is a great hope and a good reason to sit on your wallet! Now to really dream, maybe round one cameras will be usable.

[Juha Haataja]

Thanks for the clear explanation of the potential in micro 4/3 standard. Until any products are announced, it is hard to know what direction the companies will select. I hope "small and rugged" will happen.

[Martin]

Is it imaginable, that we see nearly symmetrical lens constructions, as we have now for analog and digital rangefinder-cameras?

I agree with you, that there is a great potential in the Micro Four Thirds System, perhaps something like a "Barnack-camera, a Leica of the digital age" (quoted after Erwin Putts). But what we will see in the end is written on another piece of paper.

[Ben]

I think the person being quoted is confusing retrofocus and telecentric. Retrofocus (http://en.wikipedia.org/wiki/Retrofocus) - large back focal distance; Telecentric (http://en.wikipedia.org/wiki/Telecentric_lens) - exit pupil at infinity. As I understand it, it's easier to make telecentric lenses with smaller back-focal distances.

[Matthew Allen]

Very interesting. This news has passed me by too and I wasn't even on holiday...

Cheers,
Matthew

[Gene Forsythe]

Looking at this announcement and mentally linking that to the latest sales data for P&S cameras in Japan makes me wonder if we are not on the verge of a major change in the overall camera market, one that will see the demise of the current P&S format in exchange for wildly technical camera-equipped cell phones and the new micro four/thirds style SLRs (which should still be lots cheaper than todays full-sized DLSRs).

After all, if I can get most of the functionality of a typical P&S camera in my cell phone, why carry a camera? That opens up a market for a "little bit better" camera that's just slightly larger than a P&S, and still reasonably priced. Its the one you will use for family gatherings, weddings, special events, etc. - while the cell phone camera handles everything else.

[Kjetil Høiby]

Stick a 17mm set to hyperfocal distance on one of these and a 35mm-finder in the hotshoe, and a DMD is born?

I must admit I went straight here after first reading the details on mFT only to find the "we're closed, check back in a week"-sign, thinking that was oddly ironic :-)

[Mike J.]

Ben,
4/3rds lenses are not true telecentric lenses. The word is really just used loosely to indicate image-forming light that impinges on the sensor at a perpendicular angle. Certainly, retrofocus designs are easier to design when that condition is not met.

I really don't know this for sure, but I don't believe any manufacturers of APS-C-sensor cameras have been truly strict about making lenses with perpendicularly-impinging image-forming light; the inherent problems are being better handled now in various ways, including in software and (in at least Leica's case) with directional microlenses. So it's probably a combination of the desire for freedom in design and the fact that the disadvantages can be ameliorated that motivated Olympus and Panasonic to relax this part of the standard.

Bear in mind I'm no optical expert, though.

Mike J.

[shootfirst]

This new format could be very cool, but what concerns me is that there isn't much detail on the auto focus mechanism. If this system is using contrast detection off the sensor then for me they've missed the target. Interchangable lenses and larger sensor image quality are great features, but responsiveness and autofocus speed are key.

[mike]

I'm a little put out by what I'm reading that suggests there might not be a viewfinder. Doesn't that defeat the point?

[Mike J.]

mike,
As I say, it depends on implementation. The cameras won't have a TTL reflex-mirror viewfinder, that much we know. We can guess there will be at least one LV-only viewfinder. Beyond that, who knows? Will they all be LV? Will there be viewfinder-window models or clip-on finders or--? Too early to tell.

Mike J.

[steve]

Reminds me of the Pentax auto 110.

[john robison]

"...little metal gems like miniaturized Leicas...and top quality lenses..."
Sure, no problem. And the total with tax will be $3,243.15, will that be check or credit card sir.

[André Moreau]

Welcome back Mike,

Here's my take of the Olympus M4/3. With its annoncements, Olympus has just about killed any hope for a Olympus FF camera.

Secondly, Olympus have to take into account that 4/3 never became a standard. As a matter of fact, 4/3 format is rather marginal in terms of market share. Well they keep 4/3 format? Who knows at this time.

Thirdly, M4/3 has a movie mode and EVF. The OVF has been abandonned. So, who's Olympus going after with M4/3? The digital p&s camera buyer? If so, I would not expect too much in term of high end equipment.

And does Olympus have more than M4/3 up their sleeves? New bridge cameras maybe?

[Dave Kee]

Although many people talk about whether these new cameras will be "pocketable", I am a weight weenie, and for me their weight is going to be the critical issue. The Nikon D-40 with a 18-55mm kit lens weighs 24 ounces, an Olympus E-410 with a f/2.8 25mm lens is 18.7 ounces and a Sigma DP-1 is just 8.5 ounces. If they can bring this in with a wide angle lens weighing less than 12 ounces I am in.

[John Camp]

I think there's a lot less to this fuss than meets the eye....

The essential problem with micro 4/3 is that cameras are built for human eyes and hands, and if a camera is easily usable (let's say D700-sized and smaller), then the question turns to image quality. The micro 4/3 will not be able to compete in image quality with the D700-class cameras, unless Olympus has made some break-through in sensor technology not available to Nikon, Canon, Sony, Pentax. So if you use one of these cameras, you automatically will be accepting lesser image quality, even if the camera is jewel-like with fantastic lenses, etc. All you get is smallness -- not the smallness of a true P&S, not a true pocket camera, but just a smallish camera that's not quite as good as other only-slightly-larger cameras. (Handle a Pentax. They're small.)

I think people who grew up with film haven't totally adjusted to the fact that in the past, we had only one really critical variable in photography, and that was the lenses. Otherwise, we have a light-tight box of varying quality and utility, with cheap standardized sensor material (film) available everywhere -- but the lenses were critical, and varied widely in quality.

Now, sensors are as important as lenses. Great lenses coupled with inferior sensors gives you inferior IQ compared to people standing next to you, who are using larger sensors. As far as I can tell, nobody has really been able to beat that sensor/size trade-off.

Is smallness enough to sell Micro 4/3? Bet it isn't.

JC

[hugh crawford]

is there anything in the MFC camera spec that defines the type of shutter used?It sounds like a fully electronic shutter like in that new casio would open up a lot of possabilities.

[Jay Moynihan]

hmmmmmmmmmmmm. Yep, sure. Wait and see.
I expect what was posted a ways above. Camera phones eating from the bottom, Micro-4/3 eating from the top, with LCD screens, and no viewfinders.
I too hope like Mike, for a nice little carry around though, with a nice EVF and a couple primes. Sigh.
I will also fearlessly predict DX type cropped sensors APS-whatever, migrating down also.
In the not to distant future, 35mm format body "DSLR's" with optical prisms and full live view will be "full frame" only. But the "designed for digital" cropped lenses may work on the downsized APS's?

Guess we gotta wait and see....

[Kevin]

I envision a whole range of micro 4/3rd cameras from high-end models with great build quality, weather-proofing, and a lot of features, to entry-level models with perhaps a single fixed, non-interchangeable lens. The interchangeability of lenses is obviously a big selling feature to serious photographers, but I see no reason why Oly/Pan could not also build models with a single, fixed zoom lens. This would appeal to people who want improved image quality, but are not up for the hassle and expense of buying and carrying different lenses. I would also love to see a submersible, rubber-armored version for snorkeling, diving, etc.

[HughofBardfield]

Andre Moreau's comment above is slightly puzzling - what hope was there, ever, of a FF Olympus? None whatever! Apart from anything else, that would defeat the whole principle of 4/3rds, surely?

My concern is with the future of "ordinary" 4/3rds. Those of us who bought into the concept, and have significant investment in glass (recognising that the body technology means that whatever we buy will be "obsolete" in a year or three) must wonder whether our investment is safe, or whether we will find ourselves in a stagnant backwater, just as we were with our OM4s and OM4Tis all those years ago.

Not that my OM4 doesn't still take pictures as good as the incompetence of the operator permits: so does my E1, for that matter. But I retain the painful memories of being denied access to the benefits of technology as Oly failed to update their cameras - and the anger at discovering that my expensive wide angle glass had been all-but turned into paperweights when 4/3rds came along.

Of course, Olympus have said they remain fully committed to 4/3rds proper, and I have it on excellent authority that there will be significant new additions to the Olympus "roadmap" at Photokina in a few weeks.

What they need to do to convince me (and looking at many forums, a lot of other people) is to announce a substantial upgrade for the E3 "professional" body very soon. Otherwise the echoes of Olympus's past betrayal of their customer base may overcome the sounds of marketing hype over their new baby. Will Olympus listen to this? Their track record is not encouraging.

[charlie d]

Welcome back Mike,

I for one am extremely interested in this system. Not because I have 4/3 lenses but due to the form factor.

JC, Everyone understands this argument that 4/3 will always be the ugly stepchild. If we look at it in terms of ultimate quality only we lose track of the purpose of a particular camera/system.

Why compare this not yet even a camera to a D700? The first one will be the only camera in it's class with it self as the only benchmark.

Why buy a D700 when a Hasselblad H3DII-50 exists? After all the Hasselblad is a "better" camera and the D700 does not even compete.

Grumble Grumble Grumble

[Dennis]

I don't see m-4/3 eating into the digicam or DSLR markets much. They'll probably sell plenty because Oly will likely have the market to itself (I see other manufacturers building EVIL models for existing lens mounts at some point, but not new mounts - the advantages could be low cost, quietness and low vibration, but not compactness). So Oly sells a few to people looking to step up from digicams but put off by DSLR size but mostly they sell to existing DSLR owners who want a carry-everywhere camera that uses a decently sized sensor. Their biggest competition will be the rumored APS-C compacts, depending entirely on the specs of those cameras.

With any luck, I'll own a DSLR, a compact *and* a m-4/3 or APS-C digicam long before I own a cell phone ;)

I'm a little surprised at the move; I thought years ago that Oly should have designed fixed lens compacts using the 4/3 sensor and created a market for themselves; now I wonder if m-4/3 will be a day late and a dollar short if a couple of APS-C fixed lens digicams make it to market before Oly even gets this thing in gear. If, say, Nikon puts out a $500 APS-C compact with a 35-70/2.8 (knowing Nikon, it will be an f/3.5-5.6 !) or someone comes out with even a fixed 28/2.8 I can imagine an awful lot of people deciding not to wait for m-4/3 if Oly hasn't promised specs & dates.

[Luc Novovitch]

"Thus unleashed, camera and lens designers can now employ classic wide angle lens designs unusable in SLRs, create zooms with rear elements that protrude into the camera body..."

Well... if this sensor technology is as good as described, it could mean that a quality digital rangefinder and dedicated lenses could be built. I suppose I'm not alone waiting for an alternative to the Leica disappointing foray into the digital world.

[Archer]

I guess someone dragged Maitani out of retirement ;-).

As for what sort of cameras, who knows? I do know that the market is, according to a recent survey, demanding weatherproofing, and smaller devices. Olympus is doing reasonably well with their SW P&S cameras, and I don't think that it is too much to hope for a μ43 version. Beyond that, I suspect we'll hear more by Photokina.

[agesilaus]

The idea that they are going to allow a reduction in optical quality and 'fix' that in software doesn't engender much enthusiasm in my heart. But the lack of an optical viewfinder instantly killed whatever interest I may of had in these cameras.

[Abbazz]

"But if it's true, it will be at least as important as the greatly reduced flange distance in allowing dedicated Micro Four-Thirds lenses to be significantly smaller and lighter than 35mm, APS-C, and existing 4/3rds lenses, without sacrificing optical quality".

Does anyone remember the Pentax Auto 110 SLR? It was a great little camera with a clever design, which was launched by Pentax in 1978. Unfortunately, it used the flawed 110 film cartridges and it went the way of the dodo with the whole Kodak 110 system. Here's an interesting web page about this camera:
http://www.cameraquest.com/pentx110.htm

If you have ever seen a Pentax Auto 110 SLR, you know how small it is and how tiny its lenses are. The standard 24mm lens is about the same diameter as an adult man's thumb and weights a diminutive 13 grams! And if you have ever used it, then you also know how good these tiny Pentax lenses are.

So what's my point about the Pentax 110? Just that 110 film frames measured 13x17mm, which happens to be almost the same size as the "full bore" fourthirds standard. If Pentax managed to make a standard lens for its 110 camera which was so small back in 1978, how come nobody seems able to make any lens similarly small for the fourthirds standard? The new Olympus 25mm pancake lens is 7 times heavier and 2 times longer than the old Pentax 24mm lens. Do people at Olympus really believe that creating a new standard with an even smaller frame size will help solving that incapacity?

Cheers!

Sebastien Lallement

[Amin]

Dave Etchells gave a similar analysis for the Imaging Resource. Very interesting stuff. Hopefully they will also loosen the telecentricity requirement for non-Micro Four Thirds. I think they are quietly doing this beginning with the ZD 25mm f/2.8.

While I am very excited about the medium term implications of the new standard, a few things are keeping my hopes for Micro Four Thirds in check. First, the joint press conference announcing the standard in Japan was clear that this was being directed at the "family" and "women" markets, specifically noting that they wanted to attract compact camera users who found DSLRs too cumbersome or difficult to use. Thus it seems unlikely that early products will be designed with the kinds of manual controls that we would like. Second, the prototype MFT lens being shown on various sites is a telephoto zoom with only one broad ring on it. This can only control either focus or zoom. The other control presumably will be accomplished through buttons on the camera. 3) Individuals under NDA have strongly suggested that we will be seeing some excellent EVF technology. However, chances are low that we will be seeing any sort of optical viewfinder integrated with the focus system.

[Ken Tanaka]

I'm as enthusiastic for higher-quality small cameras as the next guy. But having recently taken a somewhat whimsical first try with an Olympus E420 (a "four-thirds" camera) I can't say that I'm especially encouraged. It's a nice little "first camera" but nothing special and not the value that a Canon 450D would have been. Someone elsewhere suggested that this "micro four-thirds" concept seemed suited to development of a new rangefinder. Yuh, ok.

Personally, I'd be delighted to eventually be shown otherwise, but I don't see much future in this announcement.

[Mike J.]

Amin,
You make an excellent point--we tend to forget on these shores the extent to which the Japanese consider the "womens' market" to be separate and different. American and British marketers don't think this way to nearly the same extent.

Still, I do tend to like the things the Japanese designate as appropriate for females--the Contax Aria was one of my favorite film SLRs in its day, and it was marketed very distinctly to women in Japan.

Mike J.

[Mike J.]

"I don't see much future in this announcement."

Ken,
Quite possible, quite possible. One thing that has struck me is that if they're going for the mass market of p/s users, how do they convince them that the Micro 4/3rds options are better? That would require education about sensor size, and education is usually the last thing you want to depend on for sales. Kodak used to say about APS that everyone who attended its seminars and learned all about APS liked it. The problem being, of course, that you can't force every potential customer to attend a seminar. If the new Micro 4/3rds cameras walk and talk like p/s ducks, people will compare them to p/s alternatives. And that could make for a hard sell.

Mike J.

[Aaron]

I'm looking forward to buying a compact, fixed lens, larger-sensor camera (by who-knows what manufacurer). Hopefully sooner rather than later.

As a hobbyist with a bag of lenses for my DSLR though, I have approximately zero interest in another brand of interchangeable-lens cameras. Zip. If I'm going out to take pictures, I'll bring my camera bag. If I'm going out (and want to bring a camera, just in case) I don't bring more than one lens.

[Roger S]

Does this sensor technology mean we can get more usable rangefinders than the R-D1 or the M8?

[Rob]

This ought to be a clarion call to Leica to sort the M8 problems out, greatly reduce the price of the M digital body, and massively improve quality control.

Get that right and the new M43 will struggle.

[Lasse]

There's a translation of an interview with the head of Olympus Imaging’s SLR division here:

http://forums.dpreview.com/forums/read.asp?forum=1022&message=28933263

http://forums.dpreview.com/forums/read.asp?forum=1022&message=28933280

http://forums.dpreview.com/forums/read.asp?forum=1022&message=28933294

The interview doesn't really suggest that they are relaxing the telecentricity requirement.

[Paul]

Hi Mike (and all)
I wouldn't hold my breath for a 'professional' (waterproof, metal, etc) mFT camera any time soon as this is a P&S camera with better IQ, full stop!

The VF won't have the response of a OVF and it'll also be iffy in the dark.

It also has contrast detection AF... or a combination of CD and IR beam rangefinding a la C5060/7070. So it won't have the speed of phase detection.

In other words, it's a P&S-like camera that'll alsodo movies.

Ask yourselevs where the money is and where it isn't. IT IS in your average P&S user, it isn't with specialist niche products like well built & sealed metal cameras with 2nd class response!

I also think the wish for Leica to convert their lenses to the format is just that, a wish.

It's still exciting for Olympus/Pannasonic as if they price it like right, the small camera with the great IQ could well catch on outside photography circles.

[Todd]

I see only one person has talked about the actual size of the sensor and how it relates to image quality. How on earth is the 4/3 system going to compete with cameras with larger sensors?

I don't see the 4/3 system doing much to the market unless they become cheap. It will attract the point and shoot people who do not want to invest a whole lot of money in camera equipment but want to step up to dslr quality. I travel a lot abroad to take photos. There is NO way I would give up the size of a sensor for a slightly smaller body.

To me the more significant news is the new Sony full frame sensored camera. I see this is a bigger deal because the price of full frame sensors will drop and will be more in the mainstream. I would rather go with a full frame camera and have an additional cheap camera to put in my pocket. I think those who are really serious about photography will be carrying a tripod and other equipment with them so a slightly smaller camera is not going to appeal to them much.

[Mike J.]

Todd,
I keep saying this until I'm blue in the face, and of course you can do whatever you want, but there's no significant difference between a 4/3 sensor and an APS-C sensor. The area of the two is way too close. Slight differences are detectable technically, but no way can people tell the difference when looking at prints. The idea that the 4/3 sensor is somehow unacceptably small is the biggest canard in digital photography, and an injustice besides. And no, I do not own an 4/3 DSLR.

Mike J.

[Todd]

Hmm, I just fell upon this information which could be a more significant breakthrough. It is what I was thinking about. Why not offer a larger sensor camera but use an electronic viewfinder to reduce its size but retain the image quality of a larger sensor area. Looks like Sumsung is doing just that. Now I would be interested in this format more.

"Just weeks after Olympus and Panasonic launched the potentially revolutionary Micro Four Thirds system, in flies word that Samsung is looking to steal their thunder with a sure-to-be-incompatible alternative. Speaking at IFA in Berlin, Samsung Techwin executive vice president Byung Woo Lee confessed that the company was gearing up to introduce a new "interchangeable lens 'Hybrid' digital camera system." The first model in the still unnamed system would reportedly carry Sammy's own 14-megapixel APS-C sized CMOS sensor and a new lens mount, and while exact size specifications weren't disclosed, you can rest assured that the end product will aim to deliver DSLR-like results in a much more compact frame. As with the aforementioned Micro Four Thirds, this method will also utilize electronic viewfinders and a live rear LCD for framing, though we won't see anything on store shelves until early 2010. Talk about testing our patience."

http://www.engadget.com/2008/09/01/samsungs-aps-c-hybrid-system-to-rival-micro-four-thirds/

[Todd]

Mike J. You could be correct. I have been trying to find information on the actual image quality difference. It may be insignificant.

This makes me wonder, if the sensor is not that much smaller that the aps-c sensor why not just use the APS-C sized CMOS sensor and utilize electronic viewfinders to reduce the camera body size, then everyone could keep their old lenses? To me I think Samsungs method makes more sense.

[Todd]

One more question. Do you think the "full frame" sensor cameras will have more of an impact with professionals and prosumers? The full frame sensors cameras are now the size of normal dslrs and are dropping in price. Now that Sony is in the game I see a big potential for that. There new a900 offers what the other full-frame cameras offered at half the price.

If the price drops far enough then there is a big difference in image quality between them and the (aps-c and the 4/3 sensor) cameras. And that would entice many prosumers. I envision a sub $1,000 full frame dslr in the future.

Then there are the point and shooter who do not even want to carry around a camera the size of the micro 4/3. They want something they can stick in their pocket.

There will always be those two extremes, which I am guessing make up a sizable bit of the market. On one hand you have those who want maximum image quality for the price without giving up too much convenience, then you want those who want good pictures with a heck of a lot of convenience and simplicity.

Where would the micro 4/3 fit in?

[Todd]

I just realized my statement about lens compatibility would be retained with a aps-c sensor in cameras without the optical viewfinder is incorrect. It would still require a different lens design, correct? Because the distance from from the sensor has been reduced so much.

But still, I do not understand why they just didn't use the aps-c size sensor to begin with? Can you explain this to me?

[Mike J.]

Todd,
Try going to Wikipedia and searching "Four Thirds System." It will give you some useful background on the standard and some links for further information. There are also a number of dedicated sites, some of which are listed at the Wiki entry.

Mike J.