Modern cameras have had a terrible quarrel with the laws of physics. Manufacturers want them to be small but shoot big, bright pictures or video, no matter what the circumstances. Physics doesn't like small cameras; it still demands that a good number of photons get through the camera to its light sensor to record an image.
That's why serious photographers have stuck with big, versatile, reliable SLRs -- the type of camera with interchangeable lenses, lots of controls and a viewfinder so you can see exactly what you're getting. They weigh a ton. You may get a lousy shot with your smartphone's camera, but you'll get no shot with the camera you leave at home.
That's why Olympus and several competitors like Panasonic, Sony and Nikon have labored so hard to create cameras like the Olympus Pen Mini E-PM-1. The camera body is slightly larger than a pack of cards. The lens cap on the 14-42mm zoom lens is slightly larger than those dollar coins the government just announced it's discontinuing. But the sensor, using the Micro Four Thirds format developed jointly with Panasonic, is almost nine times larger than the pinky-nail-size little chips hidden deep behind the lens of most pocket cameras.
The Pen Mini is still too big for most pockets, even with a relatively flat wide-angle lens on the front. But the body, including battery, weighs less than 10 ounces. (Olympus' flagship SLR, the E-5, weighs 1.8 pounds by comparison.) To abuse an old saying, you can take it with you.
So what do you get for your $450? Better shots than you'll get from a point-and-shoot camera, but only under certain circumstances. Its controls are simple -- too simple, in some ways, as if it were meant as just one more snapshot camera. (It has a more sophisticated cousin, the EP-3, for $900.) In bright light it focuses quickly, and shutter lag (the maddening delay between the time you press the button and the camera actually takes the picture) is essentially forgotten. But in low light -- say, in your living room in the evening before you send the kids off to bed -- the camera hunts to focus, and images are sometimes muddy.
In that case you may want to use the flash, but -- hey, where's the flash? Back in the box, that's where. It's a teeny little attachment that fits in a hot shoe on top of the camera. Slip it into place and you're back in business, but in the meantime the kids have run off to do other things.
The hot shoe is also there if you want to use a viewfinder, something many photographers consider essential for composing good shots. They've disappeared from many smaller cameras in these days of LCD screens. Olympus will sell you a very good electronic finder for an extra $215, but then you have your choice of using the viewfinder or the flash. You can't have both on the camera at once.
All that said, there's something interesting brewing here. With people shooting casual snapshots on cellphones, camera manufacturers have had to turn in other directions -- and big black SLRs are off-putting to all but the most determined photographers. Small cameras like the Pen Mini with their interchangeable lenses split the difference -- user-friendly (Olympus sells the E-PM-1 in designer colors) but capable of using lenses that range from extreme wide-angle to a very long telephoto.
Someday the SLR will be obsolete, and cameras like this one and its brethern may be what replace it. They're not quite there yet, but they're closing in.