Digital cameras take excellent photos but aren't good at transmitting them. Cellphones are great at sending pictures but aren't very good at taking them.
Sony's masterstroke: Why not create a weird new half-a-camera, the new QX100, that contains exactly the components that a cellphone camera lacks?
It could have a lens that really zooms. It could contain serious, professional "glass" — a Zeiss f/1.8 lens. It could have manual controls, optical image stabilization and a tripod mount.
Above all, it could have a huge sensor, the digital "film." A large sensor gives you delicious amounts of detail, true colors and exceptional clarity in low light. A big sensor means less blur.
Megapixels, on the other hand, aren't a very big deal. Even so, Sony's semicamera could offer 18 or 20 megapixels — enough for even giant prints — compared with the 5 or 8 megapixels on your phone.
The QX100 ($500) is the craziest-looking camera you've ever seen. Even on close inspection, you'd swear that it was just a lens.
Somehow, into that space, Sony has crammed most of a camera. There's a 3X telescoping zoom, with a zoom lever. There's a real shutter button, a battery, stereo microphones and a memory-card slot.
There is not, however, a screen, because your phone already has a huge, really great one. So between this lens thing and your phone, you have all the elements of a top-notch photographic machine.
The QX can snap onto a plate bearing rubber-lined grippers. They're spring-loaded so that they can firmly grip your phone. That's right: You can actually attach a $500, semiprofessional zoom lens to your cellphone and take some truly excellent pictures.
To communicate with your phone, you install the clunkily named app, PlayMemories Mobile.
Once you have everything set up, the phone's screen acts as the lens's viewfinder. Using touch controls on your phone, you can zoom in and out; take a picture by remote control; and adjust the exposure, automatic and program modes, plus aperture priority mode, manual focus and white-balance options. It all works, although the camera takes part of a second to respond to your phone taps.
The QX100 is based on the best pocket camera ever made, the Sony RX100 Mark II ($750). (In other words, the QX's pictures are truly terrific.
The QX also records movies. They don't get sent to your phone; they stay on the lens' memory card. You can transfer them to your computer using the USB cable.
All of this works identically on the 18-megapixel QX10, the less expensive sibling. It costs half as much; it's about half as long and much lighter; and it zooms 10X instead of 3X.
But the QX10 doesn't offer anything like the photographic excellence of the QX100. Its sensor is no bigger than the ones on standard pocket cameras. Its lens isn't Zeiss glass, and it's no f/1.8.
And now, the bad news. As it turns out, the QX cameras' execution just doesn't live up to the ingenious idea behind them. Some of the problems:
The camera requires a cellphone-style memory card, a microSD card , which is about the size of a fingernail clipping.
Neither "camera" has a flash.
Both cameras take only JPEG photos.
The writing in the app is laughably bad.
The PlayMemories app doesn't let you review pictures you've just taken. You have to switch into your camera's Photos app for that.
But listen: Let's not mope. Let's celebrate the spirit of that spectacular central idea. Let's hope that spirit survives long enough for us to see a QX 2.0 next year.
David Pogue is the New York Times' tech columnist. He can be reached at davidpogue.com or @Pogue on Twitter. See full columns at fresnobee.com/pogue.