Megapixels measure a camera's resolution, or picture sharpness, which is particularly important to folks who want to blow up prints well beyond snapshot size. The rear camera on the iPhone 4s and later models has 8 megapixels. If you've been shopping for a digital camera of any type, you're aware that megapixels are marketed like chocolate chips: The more of them, the better. But that may not always be true (for cameras, not cookies). Although the number of megapixels matters, so do a bevy of other factors, including lens quality and shutter lag.

The cameras on the iPhone have gotten better in each subsequent model. According to Apple, the 1/3-inch sensor in the 4s can capture 73 percent more light than its predecessor, to produce stunning 8-x-10-inch or smaller prints. And to reduce distortion, the iPhone 4s has five custom lens elements versus the four lens elements in the iPhone 4. In fact all the iPhone models since then also have a five element-lens. In addition, the larger f/2.4 aperture on the 4s and 5c let more light in than their immediate predecessors. The 4s also added face detection, which helps the camera figure out whether you're shooting a portrait or taking a picture of a whole bunch of folks at once. Such optical improvements mean that the camera in the 4s started to rival many decent stand-alone point-and-shoot models.

If that last statement wasn't true by then, it was certainly true by the time Apple introduced the iPhone 5. It includes a dynamic low-light mode that can detect dim surroundings. Apple states that the iPhone 5 can also examine surrounding pixels and deduce when pixels may be out of place, such as an image of the sky with a single green pixel in a sea of blue pixels. The camera in the 5c is equally solid. But the grand prize winner here is the vaunted iSight camera in the 5s. It sports extra-large pixels (1.5 microns) that, coupled with an f/2.2 aperture, let in about a third more light compared to the prior generation, according to Apple.

That same f/2.2 aperture and those extra-large pixels also grace the 6 and 6 Plus, and on these latest models, Apple improved face detection.

This all sounds great in theory, but the bottom line is whether or not you will be satisfied with the images you shoot. The answer, at least most of the time for most of you, will be a resounding yes, especially if you use the most recent models.

And if you plan on admiring those images on the phones themselves, few camera phones hold a candle to the iPhone when it comes to their displays. Apple's iPhones of recent vintage exploit something marketers call retina display, leading to really sharp characters. The backlit 3.5-inch display on the iPhone 4s boasts 960-x-640 pixels. The 4-inch iPhone 5, 5c, and 5s offers 1136-by-640-pixel resolution at 326 ppi (pixels per inch). The 4.7-inch iPhone 6 has a 1334-by-750 pixel resolution display at 326 ppi. And the relatively ginormous 5.5-inch iPhone 6 Plus has a 1920-by-1080 pixel resolution display at 401 ppi.

The technological mumbo-jumbo may not mean much to the average person. But just realize that the iPhone display and camera will give you something to smile about.