Originally posted by mecrox Hmmn, the K-01 suggests that you cannot repurpose a DSLR by removing the mirrorbox and trying to pass it off as a dedicated MILC. You have to design everything from the ground up with mirrorless in mind, including the mount and the lenses. If you skip that bit, which Pentax did, you'll end up with a world-class embarrassment whatever the internals may be.
I think you're mistaking what they did with the K-01. What you're describing as 'have to' is what they did with the Q, not that it's been any great sales success either. The basic issue is that any MILC design involves compromise. Pentax chose to split the compromises with two different cameras. At this point, I've used examples of several MILC systems - Micro 4/3 (Olympus E-P1, Panasonic G2 and GX1), Pentax (Q and K-01), Sony (NEX-5), and Nikon (V1) - so here's my thoughts based on that experience.
(Another caveat - I far, far prefer handheld and almost never use a tripod, unless it's a mini unit to brace against my chest. I also prefer to shoot one-handed. For me, photography is mostly about serendipity instead of setup - catching an angle, or a moment of lighting, and being ready to capture it immediately.)
The basic MILC compromise is between size and image quality. To make the camera+lens smaller, you have to make the sensor smaller, reducing image quality. And redesigning the optics system requires designing a whole new set of lenses - which can be great for a company trying to sell you more gear, but is less than ideal for the photographer who has to buy into the system. Quite aside from the higher cost, you have a real problem with lens selection unless a) the company does a really great job of cranking out lenses, or b) they can get other companies to buy into new lenses. Adapted lenses can help, but at the cost of going full manual, and usually with a fair amount of awkwardness from the adaptation (adapters that extend out beyond the thickness of the camera itself, that sort of thing).
* Sony tried to cheat by putting a large sensor in a tiny body. The problem is that this just shoved the size into the lenses, resulting in a tiny body with a huge lens attached - and because of the way they cheated with the body, that huge lens is hanging unbalanced to one side, with a relatively tiny grip to control it. When I shot with the NEX-5, the drag of the lens kept tilting the image unless I consciously kept my mind on correcting it... which distracts from actually taking pictures, at least for me. The 18-55 kit lens is pretty bad (and I'd hate to think what the 55-210 would be like), but even the Sigma 19mm and 30mm feel off-balance. The lens selection itself is still pretty limited, and from what I've read most of the ones I could even think about affording are mediocre at best. The short flange distance does make it good for adapting 35mm SLR lenses, but the length of the adapter itself just makes the balance problem worse.
* Nikon went for a smaller sensor to get smaller lenses with the One system, but I think they did a bad job of it. The lenses are smaller than Micro 4/3, but not by enough to make a significant difference in handling, at least for me. The V1 itself was actually bigger, heavier, and far less comfortable to shoot with (seriously, they think a single strip on the front is good enough for a grip?) than the GX-1 or even the E-P1. And despite some reviews that liked the IQ, in my own experience I thought it was inferior to a Fuji X10 compact - let alone Micro 4/3. I've seen some stuff on adapting lenses for it, but frankly I was disappointed enough in the camera that I haven't tried doing it.
* Micro 4/3 is, I think, the most successful *single* compromise among MILC's. It's got two companies supporting it, so there's a wide variety of bodies and lenses to choose from; the sensor is enough smaller to allow smaller bodies and lenses, without compromising too badly on image quality (and the newest sensor on the EM-5 and E-PL5 is supposed to be a near equal to the NEX's APS-C, though I haven't had a chance to play with that). The bodies I've tried have also had better ergonomics, with better-balanced lenses than the NEX series. The biggest problem I have with it is that it's expensive - the best IQ bodies and lenses are well out of my reach, and the more affordable bodies have lesser IQ.
* Pentax, as I said, decided to split the difference by making two models. They pushed size/weight about as far as it could practically go with the Q, and they pushed image quality about as far as it could go with the K-01 (DSLR sensor and native, unadapted use of DSLR lenses). The sales suggest this was a poor decision from a marketing standpoint; and I admit that from a photography standpoint, if I had to pick just one camera, it'd probably be my GX-1. But after picking up a Q in last fall's model closeout, and a fire sale K-01 a couple of weeks ago, I have to admit and even promote their advantages. The GX-1 is a well-designed camera and is fun to shoot with; but the Q is even more fun to shoot, handles almost effortlessly, and can pack a full and versatile kit into a much smaller space. And the K-01 handles better than I expected (although with some significant flaws), takes beautiful pictures, and can use cheap-but-classic glass more conveniently than the GX-1 does.
So I think calling the K-01 a 'repurposed DSLR' is unfair. It really does feel to me like they decided to make a MILC that pushes DSLR quality - hence the sensor and the native K-mount - and then tried to design the smallest camera they could around that concept. I don't think it was a complete success (I'm not fond of the grip, the rubber flap, or the green/red button placement either), but I don't think it was a lazy design. And I think the Q and the K-01 do a much better job than Nikon One and NEX, respectively - Nikon and Sony compromised too much, without enough benefit to show for it.