Gadgets, Tech, and Sci News Collection: Giz Explains: What Everyone Should Know About Cameras [Giz Explains]

Giz Explains: What Everyone Should Know About Cameras [Giz Explains]: "

Talking to a camera nerd—or even reading about new cameras—can feel like translating from a different language. But it doesn't need to! Here, in this here post, is everything you need to know about cameras, without the noise.

When you buy a camera, you'll be pelted with specs from a salesperson, many of which are confusing, and even misleading. You will cower, and may cover your head for protection. He will keep pelting. And really, he has to—spec sheets and jargon are integral to camera marketing, at least for now. Here's what it all means, in one handy cheat sheet.

Types of Cameras

Before you set out to buy a new camera, or even just to get to know yours a little better, you've got to know the difference between the different types or cameras. Here are the ones you're likely to come across.

Point-and-Shoots: Also known as compact cameras. If you don't know what kind of camera you're looking for, or what kind your have, it's probably one of these. They're the smallest style of camera, typically—at least in the last few years—trending toward a boxy, mostly featureless shape. The lens is non-removable. The flash unit is built in. They have LCD screens on the back, not just for reviewing photos, but to use as a viewfinder as well. When you press the shutter button on a point-and-shoot, there is a slight delay before the photo is actually recorded. Many new point and shoot cameras will take video, and some even manage to record in HD.

Bridge/Superzoom Cameras: These cameras often look like DSLRs, but don't be fooled: They're just juiced-up point-and-shoots. They will typically come with longer lenses and slightly more impressive specs than your average P&S, and will give you a bit more photographic flexibility to play with. Sadly, they suffer from the same picture-taking delay, or "shutter lag," as point and shoots. The problem with bridge cameras, especially now, is that in order to get a decent one you have to spend at least a few hundreds dollars, at which point you may as well get a...

DSLRs: This unwieldy acronym stands for Digital Single Lens Reflex. Narrowly, this means that the camera has a mirror mechanism which allows photographers to see through the camera's lens while setting up a shot, and which flips up, exposing the image sensor (the equivalent to film in a digital camera). Widely, this means that the camera will have interchangeable lenses, a larger sensor than a point and shoot, and to an extent, more image controls. When you press the shutter button on a DSLR, it takes the photo instantly—no lag, like in a point-and-shoot. Many new DSLRs at mid-to-high price points shoot HD video; some manage 720p, some manage 1080p, but all turn out impressive results, if simply because of the cameras' lenses. That said, they're not really ready to replace proper video cameras yet, because amongother things, no DSLR to date has got the autofocus during video thing right.

These are the cameras that photographers, or people who call themselves photographers, use. They're also the ones that are capable of taking the best photos.

As a rule, DSLRs are more expensive than point and shoots. But they're getting cheaper. Much, much cheaper. Olympus, Nikon, Pentax and Sony all have DSLRs that can be had for under $500—and these are real cameras—rendering the entire category of bridge cameras kind of pointless.

Micro Four Thirds/Digital Rangefinder: Micro Four Thirds cameras are interchangeable-lens cameras, minus the straight-through-the lens viewfinder that defines a DSLR. In other words, they have larger sensors like DSLRs, have swappable glass like DSLRs, but use an LCD screen as viewfinderlike a point-and-shoot. This saves space inside the camera, meaning that—at least this is the theory—it can be more portable than an equivalent DSLR, while maintaining the same versatility and image quality. Most of them record video, too, and they're pretty good at it: They don't have the complex viewfinder/mirror system of a DSLR, so it's technically simpler to record video. Some of these cameras are styled like DSLRs, like the Panasonic Lumix DMC-G1, while some are styled more like portable cameras, like the Olympus EP-1.

This is a small category for now, and accordingly, prices are still high, starting at about $750. Panasonic and Olympus are basically the only game in town.

Sensors

The sensor is the part of the camera that actually records the image. In other words, it is your camera.

Megapixels, and image resolution: Megapixels have been central to digital camera marketing since the beginning (it just sounds like a 90s term, doesn't it?). A megapixel, quite simply, is one million pixels. If a one-megapixel image (or sensor) was perfectly square, it would be 1000x1000 pixels. They're usually rectangular, at 4:3 or 3:2 ratios, which means their resolutions look more like this: 2048x1536 pixels for a 3-megapixel camera; 3264x2448 pixels for an 8-megapixel camera, and so on.

As digital cameras mature, this number means less and less—it's easy to cram megapixels in a camera, but without good optics and light sensitivity, it doesn't mean that it's going to turn out an honest, clean, high-quality images at such a high resolution. My cellphone shoots at five megapixels, but the images look like screenshots from some kind of ghosthunting show. My DSLR shoots at 10.1 megpixels, but turns out images more than twice as clean and clear as my phone. My point-and-shoot is rated at 12.1 megapixels, but on close examination, its images are effectively blurrier than those from the DSLR.

If you're planning on making huge prints, or need to crop your images a lot, a high megapixel count is necessary, but beyond a certain point, the returns are minimal. You'll read a lot of guidance from camera manufacturers about how many megapixels you need to print different sized photos, which you can ignore, because they seem to change with every generation of cameras. Unless you're printing billboards or in magazine or something, don't sweat it too much.

Aside from indicating how many dots a camera is capable of capturing, megapixels can be a helpful indicator of how old a camera's guts may be. Megapixel count has been increasing fairly steadily over the years, so within a given manufacturer's camera line, increased megapixels could correlate to newer sensors, which could, along with high resolution, take richer, less noisy pictures.

ISO: This indicates how fast your camera's sensor collects light—the higher your ISO, the more sensitive your camera is to light, the less light you need to take a picture. And while high-ISO capability is most useful in low light, it also comes in handy when you're shooting extremely fast exposures in the daytime, like at a sports game. With higher ISOs, though, comes more noise—some point-and-shoot cameras advertise extremely high ISOs, on the order of 6400. Shots at this sensitivity will invariably look like ass. DSLRs, which have larger sensors that are better at gathering light, can sometimes shoot at 6400 ISO and higher without too much noise.

It might help to think of it like this: ISO ratings are actually a callback to the days of film. You used to have to anticipate how you'd be shooting, and buy film based on how sensitive it was, as expressed in an ISO or ASA rating. The ratings got carried over to digital cameras, despite film getting replaced with sensors.

Anyway, don't buy a camera for its ISO rating alone, because there's a good chance its top two to three settings will be useless.

CCD and CMOS: From our previous Giz Explains on the subject:

There are two major types of image sensors for digital cameras and camcorders: CCD (charged-couple device) and CMOS (complementary metal-oxide-semiconductor, sometimes also known as active pixel sensor). We're not going to get into the really geeky differences, because you don't really need to know or care. What you should know is that higher-end digital SLRs (the big cameras with a removable lens) use CMOS because it's easier to make bigger CMOS sensors; and mobile phones do because CMOS uses less power. That said, most point-and-shoot cameras and most camcorders use the more common CCD sensor.

~~Things are a little different now, and CCDs are common in DSLRs nowadays.~~ The difference for consumers is minimal—don't be alarmed to see either on your camera's spec sheet. UPDATE: As some commenters have pointed out, this isn't quite right: DSLRs are still trending more towards CMOS sensors, including most of the latest/greatest cameras. Anyway: still more of a curiosity than a purchasing point, for most people.

White Balance: Have you ever seen a set of indoor pictures that's totally, inexplicably orange? That's a white balance problem. Your camera can adjust to compensate for different light temperatures—tungsten lights have that orange hue, and sunlight will turn your photos kind of blue—and correct your image's color accordingly. Virtually all cameras let you adjust white balance with presets, though it's best if you can adjust it manually, too.

Sensor size, and crop factor: Some cameras have sensors that are roughly the same size as 35mm film, at 36x24mm. These are called full frame cameras. They tend to be more expensive—like Canon's 5D and 1D series, or Nikon's D3s—and their bodies tend to be a bit bigger. Semi-pro to pro equipment, basically.

APS-C sensors, on the other hand, are what almost all consumer DSLRs ship with. These sensors are about 22x15mm, which is significantly smaller than a full frame's sensor. Why does this matter? Larger sensors provide more room for each pixel, which makes them better at picking up light. (A bucket analogy is useful here.) More importantly for APS-C users, though, is crop factor. A smaller sensor will pick up a smaller section of what's coming through a lens, so: A 200mm lens on a full frame DSLR becomes a 300m lens on an APS-C camera, a 50mm becomes a 75mm, etc. Of course, camera manufacturers make APS-C -specific lenses which are designed for the smaller sensors, so this isn't a huge issue unles you're buying older lenses, designed for use with film.

Optics

The optics are the the parts through which your camera sees. They're the eyeballs, basically.

Swappable lenses, and millimeters: There are two kinds of swappable lenses, generally speaking. Ones that zoom in and out, which are called 'zoom' lenses, and ones that don't move. These are called 'primes.' They're all classified by focal length. Strictly speaking, focal length refers to the distance required for a lens system to focus light. In real terms, focal length correlates to physical lens length, and zoom power. 18mm focal length on a DSLR is considered wide, 200mm or more is considered zoom-y.

Point-and-Shoot Lenses, and the X Factor: The second most prominently featured number on your point-and-shoot's obnoxious feature sticker is the zoom rating. It'll be expressed as a number, with an x: 5x, 10x, etc. You'll also see a printed range, something like 5.0-25mm, which describes the focal length of the lens. Here's a trick: Divide the larger focal length measurement by the smaller one. The result should match your 'x' zoom rating, because, well, that's all it is: the quotient of the maximum lens length and the minimum lens length.

This is misleading labeling. Mounted on the same camera, a lens that zooms from 50mm to 100mm would be called a 2X lens, while a lens that zooms from 18mm to 42mm would be called a 3X lens, even though at the longest, it doesn't zoom in as far as the 50-100mm lens does at its shortest. Take this equation into account when comparing point-and-shoots, but most of all, try them. You'll see the difference.

Shutter, shutter speed, and shutter lag: You shutter is the little door that opens up between your lens and your sensor, allowing for photographic exposure. Shutter speed ranges are advertised with the intention of implying that the camera will be useful at both ends: from the 10-second long exposure to the 1/4000th-second high-speed shot. Keep in mind, for both numbers, that shutter speed alone doesn't guarantee anything. If your camera can shoot at 1/4000th of a second, but it's got a small aperture and low ISO rating, your shots will probably be too dark.

Shutter lag is something else entirely. You know how on a point and shoot, there's a frustrating gap between when you press the button and when your shot actually takes? That's it. The lower the shutter lag, the better, though many camera manufacturers don't even bother to advertise this.

Aperture: This is the hole through which light passes after its been through part of your lens, and before it hits your sensor. The bigger the hole, the more light gets in. The smaller the hole, the less light gets in. Larger apertures allow you to take pictures in lower light situations, but only allow you to focus on a thin plane—either your background or your foreground will be out of focus. Smaller apertures let you keep more of a scene in focus but they let less light through, and require longer exposure times. Apertures are described by f-numbers—these are the ration between the width of an aperture and the focal length of a lens. The smaller the number, the larger the aperture.

Optical vs Digital Zoom: Another scourge of the camera buyer is digital zoom. Optical is magnification by your lens—in other words, it's true zoom. Digital zoom is just your camera taking the optically zoomed image and blowing it up, like you'd do in Photoshop. It's only useful for framing shots and sometimes helping your camera focus properly. Otherwise, it's a gimmick: Ignore it, shoot wide and crop your shots later.

IS, or Antishake: Image stabilization is fast becoming a standard feature on even the cheapest cameras, though you'll find some sub-$150 point-and-shoots without it. The point of image stabilization is to correct for camera movements during an exposure, which cause blurry shots.

There are two types: Digital IS, which you'll find mostly in point-and-shoots, corrects the image with software, and can be somewhat effective, though the results are often passable, not perfect. Optical image stabilization physically moves some part of the camera to counteract shaking. In some cameras, like Nikons and Canons, the moving parts are in the lens. In most other other manufacturers' DSLRs, it's the sensor that actually moves to stabilize the image. Optical IS almost always works better, but it's not magic—you won't be able to shoot a freehand four-second exposure just because it's on, but you might be able to keep things together for a half-second or more.

Software

'Modes,' Face Detection, Smile Detection: Your camera's modes are assistive tools,, not hard features. They're generally just collected presets for settings that you can adjust yourself, like equalizer presets on your iPod. They can be useful, though you'll be a better photographer if you manage settings yourself.

Face and smile detection, again, are like crutches. Face detection guesses when there's a human in the photo so the camera can adjust exposure, white balance and focus to make sure that said human doesn't end up blurry. Smile detection is a crude algorithm that measures facial features, and won't take a photo until the subjects are judged to be SUFFICIENTLY CONTENTED, by which I mean they have vaguely crescent-shaped mouth holes. It's a good way to ensure that nobody is ruining a photo with a grimace. Also, to ensure that none of your photos are ever interesting.

Image formats: You digital camera doesn't have film, but your photos have to go somewhere. In today's cameras, the digitally stored photos are either JPEGs or RAW files. JPEG files are compressed, which means that they are encoded in such a way that they don't take up much space, but lose a small amount of quality. This is how point-and-shoot cameras almost always store images, and how DSLRs store images by default, generally.

If JPEGs are like photo prints (they're not, really, but bear with me) then RAW files are like the digital negatives. (In fact, one popular RAW format, .DNG, crudely stands for "digital negative"). Raw files contain almost exactly what your sensor has recorded, which means you can change values like exposure, white balance and coloration after taking the photo, to a surprisingly high degree. It feels like cheating! There is a downside: larger image files. And, depending on the type of RAW file—different camera manufacturers have different ones—you may need special software to view and edit your photos. Shoot in RAW if you can, and buy a camera that'll let you. This is a huge feature.

As a bonus, most cameras that shoot RAW will also let you shoot RAW and JPEG files simultaneously, so you have a lightweight, ready-to-print-or-upload file right away, as well as the RAW source, for later editing. It takes up a ton of space, but hey, space is cheap nowadays. Spend a few bucks on a bigger memory card, and live your life.

Video: Most new cameras, including some DSLRs, shoot video. But just because your camera shoots stills at 10 megapixels doesn't mean that it'll shoot anywhere near that kind of resolution in motion. The standard resolution for most point-and-shoot cameras is VGA—that's just 640x480 pixels of video, which is good enough for YouTube—while DSLRs, and some nicer point-and-shoots, record in either 720p or 1080p, which are HD resolutions, which translate to 1280x720 pixels and 1920×1080 pixels, respectively.

Storage

Point and shoot cameras usually come with a small amount of onboard storage. This, I'm about 100% sure, is there so that the camera technically works when you buy it, making your inevitable extra storage purchase seem more like a choice, and less like a mandatory camera tax. Anyway, with any camera, you're going to need to buy some memory, or storage.

There are a few peripheral memory card formats still kicking around (Sony, can you please just put Memory Stick Pro out of its misery? Thanks!) but there are only two that matter.

SD: Also seen as SDHC, or SDXC, these little guys are the card of choice for point-and-shoot and bridge cameras, and some newer DSLRs. They're small, they works fine, and they're available in just about any capacity you could ever want. Almost: Most cameras are only SDHC-compatible, a standard which maxes out at 32GB. SDXC, the next evolution of the SD standard, maxes out at a theoretical 2TB, though almost no cameras support it yet.

Compact Flash: These cards are chunkier, can be faster, and are more durable, and anecdotally less prone to temperature and weather damage. These are what you'll find in DSLRs.

Speed ratings: Memory cards come in different speeds. These are advertised in a variety of different ways, for no good reason. You'll see a couple of numbers on most cards, in the "133x" syntax. Ignore them—they are inflated, unregulated and therefore, basically meaningless. What you're looking for on SD cards is a Class rating, from 1-6. The official SD Association chart:
For Compact Flash cards, your best bet is to look for an actual transfer speed on the card, expressed in MB/s.