If you want to make efficient use of the image circle, then make the sensors round! What about those odd shaped hoods that are designed to block light from above but not vignette image? Or those compact wide angles whose rears protrude into the mount, with protruding tabs that assume the sensor is not square?

"rumours that Samsung is working on an EVIL camera with a 36mm square sensor."
OMG where did you hear about this? If it is real all my parers have been answered. I have made many posts regarding a square sensor should be used.

"In fact, it is that height to width ratio that helps make the 4/3rds format as attractive as it is compared to APS-C"

I agree that's why i got a Panasonic G1 and i am only now considering the NEX7 Because of everything else it has to offer. But i still wish it offered a 4:3 and 1:1 shooting aspect ratio in camera.

DSLRs aren't going away anytime soon. There are too many Pros who have a lot of money invested in them and their systems. Compare the Canon EF range of lenses to the Sony E mount range. Mirrorless cameras have a long way to go before they replace DSLRs.

why? the minolta hot-shoe design is much better and efficient then the old universal hot-shoe

Have you ever noticed, when little kids get scared or busted playing hide and seek, they just close their eyes and assume no one can see them or problem does not exist? Well thats what Canon and Nikon are doing, or maybe I should say were doing for the better part of Mirrorless existence.

They just thought if they are not going to notice it, and pretend that Mirrorless is just a fluke, the consumers will do the same. But they were wrong. I don't know about Nikon, but Canon is doing something to address this issue, or at least I've read somewhere they will be doing something.

If it was up to Canon and Nikon, we would have been using Flipping Mirrors for next 100 years. Why? because this way they don't have to spend big money on R&D, aside from occasional feature update or slight lens improvement, aka MKII this, MKIII that. Thus they can afford to spend more on marketing and advertising to promote their name and sell mediocre digicams to consumers. You know, regular day in the office.

Sorry.. mediocre digicams? You mean whatever MKII (as in 5DMKII) is a little thing to you and there was no research but lazy days hanging arround and throwing some bucks on stupid commercials to maintain the world's impression they're best?

biciclistu... first of 5DMKII is not a digicam... secondly I did own both 5d and MkII and today I only own 5D. (I will not go into details, but other then mostly improved sensor, and video it was not too much difference) Video is nice feature, but again, they were forced by innovations pushed by other manufacturers. My point is they are making good slrs and not going to go out of their way to make anything revolutionary. If they are not going to move in the right direction they will become another Xerox or Polaroid.

Canon has made some quite experimental cameras in the past decades. For example T90(1986) had a multi-spot-metering system which we only saw again in Eos 3 in 1997 and apart from that, only again in 1V SLR and 1d series DSLRs. It was among the most advanced cameras for a very long time. Just think about it, less than %0.1 of this website's community has ever seen anything like T90's metering system.

Speaking of Eos 3, again, only maybe %0.1 of this community has ever heard of eye-controlled-autofocus, where you choose the focus point in the viewfinder by looking at it.

Canon has always been innovative, they're the ones to ditch their whole lens lineup(FD) so that they could get rid of all mechanical contacts. As result, all EF lenses work on all Eos cameras, ever.

They also made the first affordable DSLR, Eos 300d. Before that we were stuck with Sony F-828 as the best choice.

But they've never been as innovative as Sony. Nikon as well, they both play it safe(r).

Then again, if Canon decides to make a mirrorless camera system, they have the chance to blow all the others out of water.

Just think about it, they could use all their EF and EF-S lenses on that body, since everything with those lenses are electronicly coupled.

But then again, the camera would have to be about the same size as NEX. Even longer since they'd use the EF adapters. Or they could ignore their current lineup and use a smaller sensor with lenses designed just for that system. I wouldn't care in such a system because I would be stuck with only a few lenses. Any camera system can only be as good as the lenses in that system.

Sony's advantage is the fact that E mount is actually for their video cameras. Nex-3,5 and 7 are just the tip of the iceberg. They have one basic and one very advanced camcoders in that system. They're better than HDSLRs in many ways. If the professionals catch up, they'll be making lots of lenses for that system.

In short, NEX system will probably live on if pro-video-shooters(TV and Cinema) catches on with that system. If Canon or Nikon would come up with a system with smaller sensors, they'd be only producing for the everyday shooters, whereas Sony is producing for a market that's much larger. But if Canon offers a small camera with APS sized sensor which could be coupled with their EF lenses(and a couple of smaller lenses which would make the consumers happy), it'll probably hurt the sales of Sony and 4/3 companies a lot.

I love how people can read the minds of Canon and Nikon, imagine some sort of thoughts or motivations, and then condemn those companies for what was imagined. Don't worry about Canon and Nikon, they will be fine. They were making cameras many years before you were born and somehow stayed in business without your guidance. Buy the camera you like. BTW Nikon and Canon are both fretting that you don't brush properly, aren't saving enough for retirement, and are bound to be headed for disaster your own self.

The key words are: been, in past and before. Yes it's obvious that they have been good and made some good decisions in past, but we are talking now. Polaroid and Kodak and Xerox all were super companies that decided not to change, got too comfortable with profit margins and lost most within few decades. But today's pace is much faster, if Canikon will not release something to compete with m4/3 and NEX soon, they will loose most of it's consumer market share within 5 years.

Oh, I thought digicam comes from digital camera which DSRLs are plenty :-) .. but again, your point is fair and I know you're right. But somehow their innovations still aren't been beaten yet, 5DMKII is still leading the pack even is 3 years old now

biciclistu, You are correct about 5DMKII and other pro cameras by both Canon and Nikon, they are all great, but its only small % of their market share, compared to their digicams (p&s) and entry level dSLRs.
I'm not sure if it makes lots of sense for Canon releasing mirrorless body with EF mount. Yes it has electronic connectors, so it will work, you are correct, but the size would still have to be almost identical to current models. (if they put FF on it will will make sense but also they'd have to make sure to make super nice EVF)

You are right about Sony's pro line video/cine cameras. Sony F3 and others are hot items now and replacing 5D and 7D for low budget production and small features. (Canon's lack of EVF and poor video compression are not helping them at all) Its fun to see Sony's 2MP sensor out resolving Canon's 21MP in video.
Anyways its very exciting times, I can't wait to see what Canon decision will be. But if I were to bet I'd put my money on new mount, maybe m-EF.

I, too, think that Nikon and Canon are moving too slowly. Nikon's Q system may debut with an undersized sensor AND a new lens system. They could do like Sony have, and design a shallow mirror less with an APS-C sensor, or larger, and make adapters so that we can use f-mount lenses.

It's not about consumers, necessarily, it's about the tech simply overtaking the past. If eye-level EVFs get good enough, there will be no need for prisms. The current crop of SLR's is too big; it dwarfs SLR's of old, and yet, SLRs get bigger and bigger every year. (Evidently, that means 'professional'.)

NEX is a GREAT way to think. I'd love a 35mm~ sensor to put an adapter and my Nikon glass on, but with an eye-level EVF, and good adapters not to mention dials and a hotshoe, I'm sold.

My need for Nikon ergonomics was flushed away when I stopped shooting sports. I want light, powerful, and the ability to use my F-mount lenses.

Obican, multi-spot metering is neither an "experimental" feature nor was Canon first with it. Within the Minolta range, the 9000 beat the T90 with a year, and you could get multi-spot metering on all Miinolta cameras in the i and xi series featuring a card system.

But the Olympus OM-4 was the first AFAIK.

Canon's most experimental contribution ever is the all-electronic mount.

but sony smartly designed the straps so that the camera hangs with the lens pointing down. The back buttons point up and not back against your body.

Oddly enough, after almost a decade of full-time work as a destination wedding/commercial photographer, I've never used AE/AF lock. Not even once. To each his own, but Sony can start with me. ;)

@MichaelSpotts: Are you using manual focus and manual exposure only?

Always manual exposure, but focus is automatic.

Count me as another...never used AE/AF lock..not even once.

No AE/AF lock? My camera has two separate buttons AE and AF lock and in some circumstances I find very convevient to use theese two controls only.
Many people think that focus and aperture have both to be adjusted at every click.