Photography is all about capturing light, and to get a photograph that is sufficiently exposed you need to capture enough of it in a short enough amount of time to free the motion of your subject. Thankfully digital cameras have come a long way over the years in improving performance at the higher sensitivities that are required to do so. You'll still get the best image quality out of a mirrorless or a D-SLR camera with a big image sensor, but those won't slide into your pocket. We've highlighted a few models here that will, and will allow you to shoot in all types of light.

What to Look For in a Low-Light Shooter
There are a few key points you'll want to consider when looking for a camera that produces killer images in less-than-ideal lighting. The first is the amount of light that the lens can capture. The technical term is aperture, but you'll also hear it referred to as an f-stop, or sometimes as the speed of the lens. The lower the number, the more light the camera can capture. Some compacts open up all the way to f/1.4, which is a heck of a lot of light. Because the scale is based on the diameter of a circle, the numbers progress based on the square root of 2. For those without math degrees, an f/1.4 captures twice the light as an f/2 lens, which captures twice the light as an f/2.8 lens, and so on.

But you can't pay attention to just one number. Take a look at the Sony RX100 II, with its 28-100mm f/1.8-4.9 lens. At its widest angle it captures an impressive amount of light, but as you zoom in the amount of light captured decreases. This is typical of most compact cameras, with a few exceptions like the Panasonic FZ200 and its constant f/2.8 aperture.

The next thing you'll want to consider is how well the camera performs when you boost its ISO, which is a numeric measurement of its sensitivity to light. It's a standardized system, and thankfully the math is a bit easier to get than it is with aperture—ISO 200 is twice as sensitive to light as ISO 100. For low light shooting you'll often find that you'll need to use settings as high as ISO 1600 or 3200. Lots of cameras can be set this high, but many will deliver images that are rife with digital noise and just plain fuzzy in terms of detail at their highest sensitivity settings.

The general rule of thumb is that cameras with image sensors that are physically larger-than-average deliver better image quality in general, and manage to squeeze more out of a high ISO image than cameras with smaller sensors. Your typical point-and-shoot camera has a 1/2.3-inch-class sensor. The best high-ISO shooter that we've looked at with this sensor size is the Canon PowerShot Elph 330 HS. It controls image noise through ISO 1600, while preserving a good amount of image detail. In a pinch, we'd feel comfortable shooting this camera at ISO 3200, even though digital noise is just a tad too high for our liking at that setting.

The next step up in sensor size is the 1/1.7-inch-class, which is about 50 percent larger in terms of surface area than the standard 1/2.3-inch size. You'll get better image detail here at all ISO settings, and cameras with this sensor size typically offer a good amount of physical controls and Raw shooting support to satisfy demanding shutterbugs.

A few high-end outliers boast even larger image sensors. The Sony RX100 and its upgraded sibling, the RX100 II, both feature 1-inch-class sensors. The surface area of this size sensor is 2.7 times that of a camera with a 1/1.7-inch sensor. So even though the RX100's lens narrows its aperture when zoomed in, at wider angles it is an impressive low-light shooter.

And, if you're willing to forgo zoom entirely, you can get a pocketable camera with an APS-C image sensor. That's the same size that's found in most D-SLRs, about 8.5 times the surface area of a 1/1.7-inch camera. The Nikon Coolpix A and Ricoh GR are two good examples of this—both offer wide-angle 28mm-equivalent lenses, and both will slide into a pocket. And, if money is no object, the full-frame Sony RX1 is the king of pocket cameras. It's $2,800 price tag will scare folks away, but it packs a 35mm f/2 lens by Zeiss and an image sensor that's the same size as a 35mm film frame—nearly 20 times the surface area of a 1/1.7-inch camera. The models below feature the best balance of light-gathering capability, high ISO image quality, and sensor size among the compact cameras that we've tested.

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