BJL

Square sensors would be a great waste of resources on sensors and in the preview screen and viewfinder ... and so would be "Golden Ratio" sensors of about 8:5 shape.

I am not sure why this myth of the Golden Ratio as the ideal shape for paintings, drawings or photographs persists despite the massive evidence to the contrary in the shapes actually chosen by artists quite consistently over the centuries. The most common choice of artists are about 4:3 and 7:5, and the vast majority of "still rectangular artworks" are in the range from 5:4 to 3:2. (Movies are a different issue; panoramic landscapes are an outlier, not the norm.)

The Golden Ratio is perhaps a nice shape for abstract forms like in architecture, but not when the actual subject matter of an image dictates the framing.

You see no added portability, despite the smaller focal lengths and smaller, shallower lens mount?

What is the equally portable APS-C equivalent of a lens selection like the Olympus 12-50, 40-150, and 75-300? (Small bodies for larger formats are easy enough; lenses are the main size constraint.)

Of course there is a trade-off : smaller kit size and weight vs better performance in high shutter-speed/low-light situations, but both alternatives make sense for different people with different priorities. And even for the same person when addressing different priorities at different times: many users of high end gear in 35mm or medium format also have an m43 kit as a lightweight option these days.

The suggestion that the only size step beyond 1/2.3” (6.2x4.5mm) worth making is all the way to the almost APS-C sized 18.7x14mm of the G1X sounds like a classic PR smokescreen:
"we do not (yet) have a certain category of product that our competitors do, so we will talk trash about that category ... until we have one to announce".

Like Canon talking down the need for mirrorless interchangeable lens systems before the EOS-M, or successive claims that Apple was not interested in phones, or e-book readers, or tablets smaller than the original iPad.

Of course there is room for intermediate size/performance trade-offs size in that huge format size gap, which is a factor of nine in sensor area and a factor of three in focal lengths needed, so that lenses of equal minimum f-stop need about 27 times the mass of glass in them. Photography has always had format choices in increments of less than three in the area of the sensor or film frame. 1“ format is near the middle of Canon's gap ...

This assumes that a sensor more than twice as large as an APS-C sensor and with the same pixel size, so considerably more pixels to read out, will some day not cost mich more than the smaller alternatives that are already meeting the performance needs of most SLR users. Maybe, but I doubt it:
(1) There is still a gap of well over $1000 between the price of entry level APS-C and 35mm format bodies.
(2) Chip prices go down mostly due to size reduction, no use for sensors at fixed 36x24mm size. Increased volume does help some through economies of scale, but those gains level out eventually.
(3) Chips larger than 33x26mm are far more expensive to make, because that is the industry-standard maximum field size for the steppers used to make chips, so that larger sizes like 36x24mm require a slower, more expensive, lower-yield process of on-wafer stitching. And there is absolutely no sign that larger format steppers are coming, with the dominant trend being towards smaller chips: see item (2).

Manuel,
Please do not say "only usable without a tripod in bright sunlight" when all you mean is that "the absolute best image quality possible is only attainable ..." for one thing, once one is insisting on absolute best image quality from a super-telephoto lens, I would think that a tripod is always necessary! Of course a $500, 430g super-telephoto lens involves some compromises in image quality compared to heavier more expensive options.

And of course I know about "high" ISO films; I suffered with ISO 800 film occasionally. My point, if you read what I said carefully, was is that in any situation where those high ISO films were acceptable, about four times that ISO speed is acceptable with a camera like the EM5, making this lens comparable in low-light handling to a 150-600 f/2-3.4 used with 35mm film. So many of us are happy to use that ISO advantage in order to greatly reduce the weight (and cost) of a super-telephoto zoom lens.

With the excellent IBIS of the EM5 and ISO 800, 1600, and even beyond quite usable, such a lens is not at all limited to "bright sunlit days". My 12-50/3.5-6.3 is certainly not.

You need to move beyond thinking in terms of the f-stops that were needed with film cameras and unstabilized lenses back in the '70’s!

@qianp2k: the Canon 100-400 both weighs and costs about three times as much as the Olympus m.Zuiko 75-300 Mk II, so your example highlights the advantages of this lens rather nicely.

Compared to the longer focal length lenses needed in larger formats to get equal telephoto reach, this lens clearly wins on size-for-reach trade-offs. Actually, what longer-than-300mm zoom lenses exist to match this lens in any larger format? Off hand, I can only think of the Canon 100-400 and Nikon 80-400, which are both somewhat larger and more expensive! (To be pedantic, if you allow the option of cropping to equal pixel count, it is the smaller photosites and thus higher resolution in "lines per mm" that allows the use of smaller lenses.)

In fact, smaller formats have always given their greatest size advantage in the telephoto regime: consider the great advantage that 35mm film SLR'S had over medium format, which never bothered to go beyond about 300mm ("150mm to 200mm equivalent").

Olympus has designed this lens primarily for use on Olympus bodies: why does that surprise or bother anyone? By having good in-body IS, lenses can potentially be lighter and less expensive; in-lens IS would simply be dead-weight for PEN or OMD users.

P. S. the main reason to choose a smaller format system like MFT is a smaller, lighter kit, including smaller, lighter lenses. Bear in mind that due to the usable ISO advantage of recent MFT sensors over film, this lens with a recent Olympus body has a high speed/low light advantage over 35mm film used with f/4 super telephoto primes. Larger, heavier digital body+lens combos can perform even better, but it should be easy to understand that for many people, the performance is good enough, and preferable to carrying a heavier kit.

On the other hand, if your goal is even better low light capabilities combined with less of the image being in focus, then a larger format is a better choice: "horses for courses".

It seems not to work on mobile devices (fine on iPad but fails on iPod), which is ironic if true.

SLR OVF's do not have nearly as much resolution as the sensor or lenses, due to using a secondary image produced by focusing the image from the lens on a frosted glass or plastic screen. From what I have read, EVFs need about 2MP to out-resolve OVFs.

And of course with zoom for manual focus, EVFs already give a far bigger and more detailed view of the subject, for far more precise focusing.

Agreed: for example, Olympus could help fix the mismatch of small NEX bodies with oversized zoom lenses, and add some very nice macro lenses, while Sony does seem to have the best sensor technology right now, and could provide PDAF in the main sensor to support 4/3 SLR lenses.

The attempt to justify the price as due to material costs is surely a lie: a small chunk of burl wood or carbon fiber wrap does not come close to adding all those thousands of dollars to the price of a NEX7.

But the promise of all three cameras having "the same style" means that we have a woody RX100 and a woody A99 coming.

But if the profits extracted from *people with too much money*(TM) goes into at last getting a 21st century (CMOS with on-sensor ADC) sensor for its MF cameras, all will be forgiven.

Louis,
Do you no longer care about an eye-level EVF, or do you plan on using a clip-on EVF?

FWIW, with my EM5 I still find the EVF best for the majority of situations, but there are also situations where the LCD is the best tool. Certainly the EVF not nearly as bad as many posters say ---probably based only on watching snap-shooters using P&S compacts rather than seeing how a careful photographer can make use of the rear screen or making a serious effort to use one themselves.

Great idea and I love Wikipedia and am interested in offering some photos, but having an Android app but no iOS app is shooting themselves in the foot for the sake of political correctness.

For motion photography, E mount is far more attractive than alpha mount: NEX bodies offer an EVF (without the light loss of a pellicle mirror system) and Sony offers multiple professional video cameras in E mount.

Designs that minimize *focus breathing* are another constraint. That is, with many lenses, changing the focus changes the field of view, and cinematographers care about avoiding that far more than still photographers do, to avoid the framing changing during a shot as the subject moves closer to the camera and focus has to follow.

Why the anti-Japanese rant? The 5d3 is Japanese too! And what is the equivalent of the 90-250/2.8 for the 5d3?

I agree that the 14-35/2 was rather pointless, and even the 35-100: telephotos are were a smaller format has its main advantages. For example, 35mm format still has no good match for my 50-200/2.8-3.5 at comparable size and weight, so I would love a new body that gives good AF with it ... while also accepting m43 lenses, maybe with in-sensor PDAF as in the Nikon One bodies.

1. It was never claimed that 5MP is enough for all (then again, nor did Bill Gates ever say that 640K will always be enough). An early sensor road map already went to about 12MP.
2. The claims on size and weight was for the mainsteam lenses that most 4/3 users would have,, compared to the available lenses of twice the focal lengths for 35mm. And indeed things like the 14-42 kit zoom, 50-200/2.8-3.5 and 100-300 zoom are smaller and lighter than 28-85, 100-400 and 200-600 zooms, especially since the last two do not exist. Of course there is a trade-off beween size and speed, but a lot of people are happy to make that trade off with the far higher ISO speeds possible with digital compared to film.

Every mirrorless system except Canon's has models with EVF and models without, so no-one is being "forced" --- except maybe Canon loyalists who refuse to consider any other brand.

Maybe you are one of those people who is bothered by the existence of an option that does not interest you.