Buying a camera: everything you need to know

A guide to this guide

As with our smartphone buyer’s guide, you should be careful not to treat this as a definitive dictum on what to buy. What we’re seeking to do here is help you make an informed decision by separating the meaningful data from the meaningless. This is a guide to discerning the things that will make a recognizable difference in your photographic experience and results. We’ve selected a few of our favorite cameras in the categories below, but those will change over time, whereas the rest of this advice will (hopefully) remain relevant for a long time to come.

Basics of photography

Basics of photography

Every camera, from the tiny webcam embedded in your laptop to the full-frame pro cameras built by Nikon and Canon, operates under the same set of basic principles. They come from the very name of photography, the roots of which are the Greek photos, meaning light, and graph, meaning to draw or record — ergo, a photograph is essentially a map of light. When you take a picture of your favorite cityscape, you’re not actually documenting the streets, or the skyscrapers, or the milling crowds — you’re drawing up a recording of the light reflecting off of them.

The most common technique for making this recording is by channelling light through a lens onto a photosensitive material that soaks it up and turns it into an image. That light-absorbing canvas was once film, which has since been replaced by electronic sensors in modern digital shooters. In either case, initiating the light capture is done by opening a shutter in front of the photosensitive surface. By adjusting how long that shutter stays open (shutter speed), the sensitivity of the digital sensor (ISO), and how much light passes through the lens (aperture), you can control exactly how your image appears.

Since light is the only information your camera collects, it should come as no surprise that well-lit scenes typically come out looking sharper and nicer than dark and moody shots illuminated only by a streetlight — more light just gives you more information to work with. When shooting in the dark, the camera must work either harder (with higher ISO) or longer (with a slower shutter speed) to properly recreate the image in front of it. That’s where the flash comes in, a strobe of white light synchronized with the opening of the shutter. It comes with tradeoffs of its own, though: the strength of the flash can wash out fine detail in nearby subjects or lead to the infamous red-eye effect. Tripods are also invaluable in counteracting the blur caused by shaky hands. Unfortunately, they can do nothing about motion within your composition, and they aren’t exactly portable.

Ultimately, the number one lesson in photography is that there are always tradeoffs. If you want the best possible image quality, you’ll need specialized, expensive, bulky equipment. Should portability be your highest priority, you’ll have to accept that some photos and creative ideas will be beyond your reach. There are a number of other considerations to take into account when composing an image — and, consequently, choosing the best camera for the job — which we’ve detailed below. Once you’ve wrapped your head around what they will mean for your intended photography adventure, you should have a good idea of the kind of camera that will best suit your needs.

The key settings

For some help calculating the depth of field for your chosen camera, aperture setting, and focusing distance, you can use Simple DoF on iOS or DoF Calculator for Android.

ISO

Coming from the International Organization for Standardization, ISO (it’s not an acronym) describes the light sensitivity of your camera’s sensor set against a common standard. It was originally known as “film speed,” as it was a static measure of the amount of light a given type of film could absorb, but in modern digital cameras ISO can be adjusted up and down. Higher ISO means a brighter image, which is achieved by digitally amplifying the information collected during exposure. It’s an imperfect process that generates errors, which become apparent in your pictures as discoloration and noise — the unattractive speckling effect you usually see in low-light photos.

The quality of your camera’s sensor and noise-reduction processing will affect the maximum ISO at which you can produce images that are still worth using. From among the cameras we’ve tested ourselves, Canon’s 5D Mark III and Nikon’s D4 are the best in that respect. They can shoot at ISO 12,800 the way most cameras perform at ISO 1000, allowing you to keep shooting in significantly lower light.

APERTURE

Measured using the horribly confusing f-number scale, the aperture is another dead-simple setting saddled with obtuse nomenclature. Basically, most lenses have the ability to constrict the light that passes through them using an internal element (called a diaphragm), which can be extended and retracted using controls on the camera. If you want more light in your image, you pull that diaphragm back as far as it goes, or if you need less, you extend it and limit the incoming rays to a narrower, more focused hole. Aperture, therefore, is just a relative measure for the diameter of your lens opening. Lower f-numbers indicate a wider aperture, with f/2.8 and below being the extremes, while higher ones signify that more light is being blocked.

One side effect of a wide-open lens is that it lets in a lot of unfocused light rays. The result is a shallow depth of field, meaning anything in front of or behind the area on which you’re focusing will appear blurry. Wide aperture settings tend to constrict the in-focus area to a razor-thin sliver, particularly on nearby subjects, giving you the much-desired soft background “bokeh” effect.

When you want a larger focus, the obvious countermeasure is to tighten up the aperture to f/8 or narrower — it bundles up the incoming light into a more focused beam, which will result in greater depth to your focus area. The most extreme depth of field effects are the exclusive preserve of large-sensor cameras; you simply can’t achieve the same defocusing effect with smaller sensors, which retain a generous in-focus depth even at f/1.4.

SHUTTER SPEED

Shutter speed controls how long the camera spends collecting light, as opposed to ISO and aperture, which direct how much light is absorbed at once. It’s measured in fractions of a second, so a shutter speed of 1/125 means the shutter is open for one 125th of a second. Higher shutter speeds mean the camera captures a shorter period of time, which is key for getting blur-free action shots, while lower speeds allow you to soak up more light, albeit at the risk of blurry results if your camera and subject aren’t still.

Of course, you don’t always have to fear motion blur. Strap your camera to a tripod and you can exploit the blur to your advantage — that’s how the pros create those pictures of highways decorated by streaks of light or waterfalls that look like they’re composed of cascading wisps of smoke instead of frozen drops of water. Most of the time, you’ll want to match your settings to your circumstances, but it’s also good fun to sometimes start with a given set of attributes and rearrange your scene to match them.

Other features that matter

The trifecta above represents the most important controls on your camera, but there are other attributes you need to be mindful of in the pursuit of the best image quality.

LENS SHARPNESS

You can tweak your settings as much as you like, but without a truly sharp piece of glass to filter light through, your pictures will never look their best. The distinction between sharpness and softness in imaging is one of detail: sharp photos retain a clear separation between edges and colors right down to a pixel level.

Unfortunately, nobody has yet invented an easy metric for quantifying lens quality, so you won’t be able to simply walk into a store and order up the Superlative Edition of your favored lens. Part of the problem is that lens performance varies both with aperture and zoom level. The sharpest lenses at f/4 are typically f/1.8 or f/1.4 lenses that have been pulled back from their highest setting. Similarly, lenses start to exhibit distortion at the extreme wide (16mm and lower) and telephoto (135mm and above) ends of their zoom range, which some cameras are able to automatically correct for with software.

There are a couple of easy guiding principles that can steer you in the right direction. First: construction materials matter. Canon’s L series of lenses and the higher end of Nikon’s Nikkor line are both built out of real glass on the inside and extremely robust materials on the outside. The kit lenses bundled with DSLRs and the non-removable lenses on cheaper cameras are made from plastic both on the inside and out, which makes them less reliable in the long term and less impressive when you come to review your results. That’s not a universal rule — there are some exceptionally good lenses with plastic optics — but generally, you’ll be able to tell a good lens by its considerable weight and durable feel.

The second point to remember is that prime lenses — those without a zoom function, whose focal length is fixed — tend to perform better than zoom lenses thanks to their simpler construction. For the absolute best results, you’ll want a camera capable of exchanging lenses, along with wide-aperture lenses at each of the most common focal lengths: 24mm, 50mm, 80mm, 100mm, and 200mm, for instance. That’s more than a backpack’s worth of gear to heave around with you (and quality glass weighs quite a bit anyway), so do it only if you’re unwilling to compromise a little sharpness for a lot more flexibility.

AUTOFOCUS

A common misconception is that shutter lag actually has anything to do with the shutter. Sure, there’s a minuscule delay between the instruction to open and the shutter actually opening, but the lion’s share of lag actually comes from the automated focusing and metering systems. Metering is where the camera judges how long it needs to expose the image for, while autofocus is a little more self-explanatory. Cameraphone makers have gotten wise to the fact that people want to see the picture taken the moment they press a button, so we now have phones that continuously refocus and re-meter the scene so as to be ready at a moment’s notice. Samsung even features a “Best Shot” feature on the GS4, which takes a dozen photos while you’re focusing and firing and then chooses the best one automatically.

Every phone and camera maker is trying to dodge the problem of focusing speed, but the only true solution is more focusing points on your camera combined with a faster focusing motor for the lens. The reliability and speed of autofocus, particularly in low light, is one of the ways in which professional cameras still stand head and shoulders above the rest. Canon’s EOS 1D-X packs in a whopping 61 AF points, 41 of them of the more precise cross-type variety. Stick a fast-focusing lens on that camera and you can bid adieu to shutter lag.

SENSOR SIZE

If there’s one rule to follow in photography, it’s that bigger sensors mean better photos. That’s a generalization, of course, but it’s based on a very basic empirical truth: the bigger the photosensitive surface area, the more light is taken in at a time. Practical evidence for this is abundant, from the Nikon 1 series that disappointed everyone with its undersized CX sensor, to the Nokia Lumia 1020, the best cameraphone on the market largely thanks to its enormous 1/1.5-inch sensor.

Full-frame cameras derive their name from the size of their sensors, which match the “full frame” of 35mm film, and are predictably the professional’s favorite option. With a full-frame camera, a 24mm lens gives you exactly that focal length, whereas with smaller sensors, you’re subject to a crop factor that tends to turn everything into a slightly more zoomed-in version of itself (i.e. if the sensor is 1.5 times smaller than full-frame, as with Nikon’s popular DX format, you get 1.5 times the focal length; with a 24mm lens; that’d mean an effective focal length of 36mm).

Alas, price and sensor sizes scale rather proportionally, so medium format and full-frame cameras are usually outside the reach of most enthusiasts, which is why the most popular digital SLRs like the Canon Rebel T4i today feature the APS-C format. It’s a happy compromise.

MEGAPIXELS

Strictly speaking, a megapixel contains 1 million pixels, but it’s somewhat meaningless to know that your camera shoots 10 million pixels at a time. What you want to know, and what the megapixel count truly tells you, is how big you can make your image without having to enlarge it digitally (and suffer the resultant degradation in image quality). A 3-megapixel photo is more than dense enough to be printed out at the US standard 6- by 4-inch size at 300ppi, while 9 megapixels get you closer to a regular sheet of paper at the same density. Compromise a little on the pixel density, say down to 200ppi, and you’ll get massive printouts from a humble old 12-megapixel shooter. Now, there are no guarantees that the actual photo would look good — megapixel numbers only measure the number of data points recorded by the camera — but at least you’ll be able to do it.

Practically speaking, however, you’re not likely to need such huge images. Most digital imaging ends up being consumed on computer screens, and if all you need are new profile shots for Facebook even a solitary megapixel will suffice. If you’re shooting for billboards, murals, or other enormous photo sizes, you should get all the megapixels you can (like the whopping 36 from the Nikon D800) but for the average photographer, other specs matter far more.

VIEWFINDER / LCD

Optical viewfinders are a funny thing. Until you use one, you wonder why everyone bothers with the effort, then you get your first DSLR and suddenly you can’t live without one. Mirrors in SLR cameras reflect the exact image that will be imprinted onto the sensor through a sort of porthole atop the camera: that’s your viewfinder. Once again, the more expensive models offer a more luxurious experience, with the Canon 7D and Nikon D700 featuring bigger, more comfortable viewfinders than entry-level DSLRs. Electronic viewfinders (EVF) are getting much better and starting to compete, particularly in Sony’s line of single-lens translucent (SLT) cameras like the A77, and they offer helpful guides and more information to make your shot better anyway. It’s features vs. accuracy, and while the purists tend to stick with optical viewfinders, the electronic variety is catching up quickly.

If your camera doesn’t have a viewfinder, then you’d better make damn sure it’s equipped with a good LCD. You’ll be using it to both frame and review photos, so any shortcomings in terms of color fidelity or resolution can force you into a guessing game you don’t want to play. LCD resolution is measured in dots, with 230,000, 460,000, and 920,000 being the typical values. The more dots the better, obviously, but do take a moment to check out the quality of the screen as well. Sony and Samsung are using OLED displays in some of their latest cameras, which look fantastic. Touchscreens are finally starting to get good, too, from the tap-to-focus features on the Olympus PEN E-P5 to the completely touch-friendly Canon T4i — they’re not essential yet, but are increasingly a great thing to have.

WHITE BALANCE

Like a big-name actor who’s too important to sit in the middle of the cast list but not so crucial as to headline the show, the camera’s white balance (WB) gets a dedicated slot at the end. This is the function that everyone leaves on auto, which is why the majority of indoor pics on Facebook look yellow. In simple terms, cameras are a bit dumb. If you don’t tell them that you’re under incandescent lights (which cast a yellow hue), they won’t account for it and will try to balance the colors before them based on their presets. All modern cameras have a WB preset for artificial lighting, but only the more professionally inclined ones give you granular control over white balance and the ability to easily tweak it on the fly.

The best solution we’ve found for overcoming unnatural color tinging is to feed your camera a sample image. The majority of DSLRs now have the option to set WB by taking an image of something that you know is white under the particular lighting conditions you intend to shoot in. Thus, when the camera snaps a nice white sheet of paper under the lurid orange and violet lights of a trade show floor, it’ll calibrate itself to know that white looks a little different at that spot.

VIDEO CAPABILITIES

It was only a few years ago that video recording was considered a novelty in still cameras, but today HD video is a standard, and assumed, feature. Still, there are pitfalls to beware, such as a selection of cameras that will lock the focus and zoom when video recording starts (for example, the otherwise excellent Canon S95), significantly limiting your options. Reliable autofocus, in the cameras that are capable of it, remains a mirage. You’ll do well to learn to love manual focus if you want your videos to be free of the irritating focus jumps that cameras do when they get confused as to what you’re trying to film.

Cameras with larger sensors make capturing video a harder process compared to simpler point-and-shoots, owing to their greater sensitivity, bulkier bodies, and typically mechanical zoom and focus mechanisms. They give you more to worry about, as lens operation noises are often picked up by the integrated microphone. However they also provide access to a range of cinematic effects that smaller cams can’t touch. Want to start your movie masterpiece with a gorgeously circular bokeh that gradually comes into focus on your leading man? You’ll need something in the class of a Canon 60D with a wide-aperture lens to match.

ZOOM

Zoom is a simple concept — it’s how close you can get to whatever you’re shooting without having to physically move closer — but it’s not always obvious what you’re really getting. The actual x-multiple of your zoom is much less important than the angle measurements at the widest and closest settings, which measure how much you can fit into your photo. A camera that starts at 28mm and has 10x zoom will ultimately get closer (280mm) than one that begins at 24mm (240mm when zoomed in), though the tradeoff is a slightly smaller field of view when you’re zoomed out. If you want to be as close as possible to your subject, the most important number is the telephoto angle — more so than the x-multiple.

But be warned: cameras with huge zoom tend to be hard to hold steady when zoomed in, so getting sharp photos might be tough even with the best image stabilization. Additionally, as we’ve mentioned, great zoom comes with image quality dropoffs — lens makers have to compromise on something, so if you’re going after a massive zoom range, it won’t deliver sublime images the way a fixed focal length might.

When it comes to zoom operation, fixed-lens cameras have the upper hand. They usually have powered zoom mechanisms, allowing you smooth control at the press of a button. Interchangeable lenses are more fiddly for the newcomer, as their zoom is usually (but not always) controlled mechanically with a ring around the body of the lens. That gives more granular control to those who want it, but can be off-putting to the casual user.

Finally, do yourself a favor and ignore the very idea of a "digital zoom." It’s done either by enlarging the picture (and reducing its quality) or cropping down to a smaller area of the sensor, both of which you can do much better with dedicated post-processing software on your computer — a few phones like the Lumia 1020 offer clever ways to zoom and re-process on your device, but they can’t match Photoshop or even your average desktop viewer.

IMAGE STABILIZATION

As with digital zoom, digital image stabilization (IS) is more of a marketing ploy than a useful feature. The optical stuff, however, is a whole other story. Lenses with optical IS are equipped with internal elements that move in the opposite direction of any small movements you make, steadying the image that arrives onto the sensor. Nikon’s "Vibration Reduction" is particularly effective, allowing you to shoot at two or three steps slower shutter speed than you usually would be able to without motion blur. For example, if 1/40 shutter speed is your floor before you start seeing blurring on a regular lens, its VR version will move that down to 1/25. Canon’s version of this is called the "Optical Image Stabilizer," Panasonic’s is "MegaOIS," and virtually every other camera and lens maker has its own variety too.

Sony and Olympus have made a habit of building image stabilization right into the body of their DSLRs, simplifying lens design and reassuring users that all of their lenses will be stabilized. Ultimately, whichever system you choose, each serves the purpose of reducing the deleterious effects of unintended motion and should be considered highly desirable in a camera. If you’re going after a shooter with a long telephoto zoom, optical IS should be the first thing you look for.

Wrap-up

Buying a camera’s never been easier — it’s hard to get one that won’t take decent pictures without a lot of effort — but buying the right camera still takes some doing. Ultimately there are a lot of things to consider, and a lot of numbers to ignore, but the key is to figure out what kind of photographer you are.

If you’re going to be running after your kids taking pictures, you probably don’t want a big, bulky DSLR – look at mirrorless cameras like the Panasonic GX1 or even point-and-shoots like the Canon S110. Maybe even make sure you buy the right phone, from the Nokia Lumia 1020 to the iPhone 5. But if you want the best, biggest, most controllable photos money can buy, make sure you buy a camera you can grow into. DSLRs offer more control and more lenses, and they’re capable of capturing a wider range of photos and video.

It’s certainly true that the best camera is the one you have with you. But the best photos come from having the right camera with you — so shop carefully, don’t forget that more money and more megapixels don’t always make great cameras, and always remember your exposure triangle.

Happy shooting!