The iPhone has a pretty good camera. 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 iPhone 5s, 6, and 6 Plus have 8-megapixel iSight cameras (the one on the back) and 1.2-megapixel FaceTime cameras (the one on the front); the new iPhone 6s and 6s Plus have 12-megapixel iSight cameras and 5-megapixel FaceTime cameras.

If you’ve ever shopped 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, shutter lag, and even the size of the individual pixels in the sensor (which, for those who concern themselves with such things are 1.5µ pixels for the iPhone 5s, 6, and 6 Plus and 1.22µ pixels for the new iPhone 6s and 6s Plus).

µ is the symbol for micron or micrometer, and it represents one millionth of a meter (or one thousandth of a millimeter, or around 0.000039 inches.)

And most camera phones can’t hold a candle to the iPhone when it comes to showing off images. Apple’s iPhones of recent vintage exploit high-resolution Retina displays, leading to super-clear images and videos, and ultrasharp text.

The iPhone 5s has a 4-inch display with 1136-by-640-pixels (326 ppi — pixels per inch); the iPhone 6 and 6s have 4.7-inch displays with 1334-by-750-pixels (326 ppi); and the iPhone 6 Plus and 6s Plus have huge 5.5-inch screens with 1334-by-750-pixels (401 ppi).

But numbers don’t tell the whole story. The bottom line is whether or not you’ll be satisfied with the images you shoot. Most of you will be more than satisfied most of the time, especially if you use the most recent model. Still, keep your expectations in check and don’t expect to produce poster-size images from low-light shots.

If you have an iPhone 6s or 6s Plus, you should know a few more things about your camera.

You should definitely check out the new Live Photos feature, which goes far beyond snapshots and captures moments in a breathtaking fashion. You shoot photos as usual, but when you press them in the Photos app, you see the 1.5 seconds immediately before and after the shot, which is ever so much more satisfying than an instant frozen in time.

The two new iPhones are the first to shoot 4K video (3840 x 2160 pixels). And both sport much better FaceTime cameras and introduce Retina Flash, which uses the iPhone screen as the flash for the camera, enabling you to shoot wonderfully bright selfies even in dark places.

Last but not least, the improved optical image stabilization in the iPhone 6s Plus helps you capture better video and is especially useful for low light situations.