Just by looking at it, you’d never guess that Sony’s new Alpha A300 digital camera represents a huge technical breakthrough. To discover what it is, you need a tour of its innards. Keep hands and feet inside the tram at all times.
On an ordinary single-lens reflex camera (those big black pro models), light enters from the lens and is split by a semi-transparent mirror. Part of the light goes to the eyepiece viewfinder, and the other part goes downward to the autofocus sensor.
When you press the shutter button, that mirror flips up out of the light’s path, revealing — aha! — a small rectangular image sensor, the computer chip that records the photo.
Already, you’ve learned enough to answer one of the great digital camera mysteries: Why must you hold these cameras up to your eye? Why can’t you frame a photo using an S.L.R.’s back-panel screen, as you can on a little pocket camera?
Actually, a few recent S.L.R. models do, in fact, have this Live View feature, but it’s mostly a disaster. It works by flipping that mirror up out of the way, so that light from the lens hits the image sensor, which feeds the image to the screen. Trouble is, once the mirror goes up, no light hits the autofocus sensor, so the camera can’t focus.
So here’s what happens when you press the shutter button. There’s a noisy clank as the mirror drops down again; the screen goes black; the camera computes focus and exposure; the mirror lifts again; the screen comes back to life; and finally — a second or so later — the shot is recorded.
In other words, Live View on existing cameras is slow, noisy and deeply confusing. All of this silliness arises because the camera’s image sensor must do double duty: it’s responsible for supplying the screen with a live preview and for recording the shot.
Sony’s technical breakthrough on the A300, therefore, was this: "Duh! Put in another sensor!"
On this camera, turning on Live View sends light from that main mirror onto a second sensor, one that’s devoted solely to feeding the preview screen. The autofocus sensor works normally as you compose a shot, since the mirror never has to flip up.
As a result, Live View is a completely different experience. The camera focuses quickly as you aim the lens, without ever blacking out the screen. When you press the shutter, the screen doesn’t go on-off-on, there’s no loud clacking, and there’s no baffling exhibition of mirror calisthenics inside the camera.
In this regard, using the A300 can feel a lot like using a compact camera. That’s precisely what Sony was hoping; it’s aiming this 10-megapixel model ($763 with starter 4X zoom lens) at people who are graduating from pocket cameras to something more serious.
(For about $140 more, you can buy this camera’s 14-megapixel sibling, the A350. Don’t fall for it. Ten megapixels is already enough resolution for prints the size of a minivan; 14-megapixel photos just eat up your hard drive faster and slow the camera. Furthermore, if you do the math, you’ll discover that a 14-megapixel photo contains only 18 percent more pixels in each dimension than a 10-megapixel shot — not 40 percent, as instinct might suggest.)
Now, serious photographers traditionally snort at the whole idea of composing shots on the screen. Only an eyepiece viewfinder shows the true scene as the camera sees it.
But when it works properly, Live View can contribute mightily to your photographic success — especially when the entire screen tilts up or down, as it does on the A300.
For example, you can now shoot a parade over the heads of the crowd in front of you. You can shoot pets and babies at their eye level without having to squat or kneel. And you get infinitely better photos of young or camera-shy subjects when you’re smiling and making eye contact than when you’re hiding your face behind a piece of Darth Vader equipment.
(Last weekend, my adorable but camera-shy 3-year-old proved this point emphatically. About the only decent photos I got of him were the ones in which I held the camera at waist level with the screen tilted up.)
All That Said .. How Do the Pictures Look?
Finally, because the screen doesn’t black out while you’re shooting, the A300 is the first S.L.R. that lets you track a moving subject on the screen, shooting all the way. Too bad it manages fewer than two shots a second.
Sony’s perfection of Live View would be newsworthy even if it were the camera’s only notable twist. But ever since it bought Konica Minolta’s digital camera business two years ago, Sony has been tinkering in the halls of camera innovation, determined to catch up with Canon and Nikon.
All state-of-the-art S.L.R. features are present, including a system that shakes off any dust that may have drifted onto the sensor during a lens change; a battery gauge with actual percentage numbers ("74%") instead of four crude line segments; and an autofocus that begins to work the instant you hold the camera up to your eye, thanks to a proximity sensor.
Amazingly, Sony has finally quit trying to ram its proprietary, expensive Memory Stick cards down our throats; the A300 accepts CompactFlash memory cards instead — the least expensive, most rugged, most capacious type available.
The button layout and software design are a delight, too. Little things like a satisfying, clicky Off-On switch, dedicated self-timer and ISO (light-sensitivity) buttons, and scene-mode dial (presets for Portrait, Close-up, Sports and so on) let you operate this thing with a minimum of hunting through the sullen little manual. For an S.L.R., it’s quite small, and it feels terrific in your hand.
The big question, of course, is, how do the photos look?
In good light, they look sensational. Colors are vivid, contrast is excellent, subjects are razor-sharp. And since this is an S.L.R., there’s no shutter lag — that half-second delay after you press the shutter button, as there is on compact cameras.
Still, you’ll realize soon enough why this is a $760 camera, not a $1,500 one. In low light, the A300 simply doesn’t soak up enough light. Capturing subjects in motion indoors is just about hopeless without the flash, even at this camera’s maximum (and grainy) 3200 ISO setting. Blur is a huge problem in those situations.
At such times, you really see the difference between Sony’s in-body stabilization system and the in-lens systems on Nikon and Canon S.L.R.’s.
True, the in-body approach saves money, because it stabilizes every lens you attach; but the in-lens system, where the stabilization is tailored for each individual lens, just works better.
Note, too, that Live View depletes the battery a lot faster than using the eyepiece viewfinder. One charge can take 750 shots with the screen turned off, but only about 400 shots with it turned on. That’s not much better than what you’d get from a compact camera.
Other nits: There’s no top-mounted status screen. It would be nice if the screen swung out and rotated (for self-portraits, for example) and not just up and down. And if you’re used to using the A300’s rivals, the viewfinder feels a tad claustrophobic.
Even so, the A300 is a home run for its intended audience: first-time S.L.R. owners. It’s more camera for the money than its closest competitors from Canon or Nikon. It’s a pleasure to hold and to use; the pictures generally look superb; and the uncompromised Live View feature and tilting screen grant you shots you simply can’t get with other S.L.R.’s.
Until recently, S.L.R. stood for single-lens reflex. But on the A300, it has a whole new meaning: Sony’s Live-View Revolution.
David Pogue is a columnist for the New York Times and contributor to CNBC. He can be emailed at: firstname.lastname@example.org.