Interchangeable-lens cameras

Cameras in this category consist of two components: a camera body, which contains the guts of the picture-taking system, and a lens, which you attach to a mount on the front of the body.

What does this flexibility give you? Well, as of yet, no one has invented a single lens that's perfectly suited to capturing the entire range of subjects photographers may want to shoot. A lens designed to produce an extreme close-up, for example, has different optical qualities than one engineered to capture a faraway subject. Ergo ipso facto, we have the interchangeable-lens camera, which enables you to use whatever lens your subject demands.

Within this category, you find the following types of cameras:

• dSLR (digital single-lens reflex): The top two cameras in Figure 1-4 are dSLRs. (More about the name momentarily.) Although dSLRs were once large, heavy, and complicated, manufacturers now also offer models geared to novice photographers as well as advanced shooters. High-end dSLRs still remain fairly large, but entry-level and intermediate models are available in significantly reduced sizes. The smaller of the two dSLRs in Figure 1-4, for example, isn't much wider than the iPhone 6 that I included in the foreground to give you some frame of reference.

  Okay, about the name: The d in dSLR represents digital, distinguishing a digital SLR from film models, which have been around for a long time. SLR stands for single-lens reflex and refers to the viewfinder technology used in this type of camera. The name stems from the fact that the SLR viewfinder involves a series of mirrors that reflect (reflex) the light coming through the lens to the viewfinder display.

• Mirrorless cameras: With this type of camera, the mirror-based viewfinder system is gone — thus, it's mirrorless. Taking out that mirror assembly enables mirrorless models to be much smaller and lighter than dSLRs, which is why you sometimes hear them referred to as compact system cameras. The bottom-left camera in Figure 1-4 is a mirrorless model.

  Some mirrorless models do away with the viewfinder entirely; you compose the image using the monitor on the camera back. Others incorporate or enable you to attach an electronic viewfinder, which provides the convenience of a viewfinder without taking up as much space as an optical viewfinder, which is the type used in a dSLR viewfinder. The section “Viewfinder: Optical or electronic,” later in this chapter, has more details.

• Rangefinders: Figure 1-5 gives you a look at this less-common variety of interchangeable-lens camera. At first glance, rangefinders look a lot like compact system cameras, but they work quite differently. Traditional rangefinders use a different focusing system than other cameras. The viewfinder displays two views of your subject, and you determine the focusing distance, or range, by turning a ring on the lens until the two images align. However, some rangefinder models also offer other, more standard autofocusing options.

Fixed-lens cameras

Again, by fixed lens, I mean a lens that's permanently paired with the camera body. Cameras in this category fall into two camps:

• “Real” cameras: That is, a camera whose sole purpose is photography, as opposed to a computer device or phone that sports a camera.

  Most people refer to these cameras as point-and-shoot models because they offer automatic settings that enable the novice photographer to, well, point and shoot. Yet I hesitate to use the term, because higher-end fixed-lens models do enable you to control exposure, focus, and other picture settings. And although you can't swap out lenses on these cameras, some models have zoom lenses that reach from wide-angle to telephoto views, so you still enjoy lots of picture-taking flexibility.

  Whatever you want to call them, these cameras come in a variety of sizes, shapes, and colors, ranging from models that look like a small dSLR or mirrorless camera to pocket-size wonders that make the latest smartphones look huge. You also can find models specifically designed for rugged use, offering features such as shockproof and water-resistant cases. These models are great not only for outdoor adventurers, but also for young photographers who may not always be as careful with their devices as the adults in their life would like them to be. Heck, I certainly don't qualify as a young photographer (although 56 is the new 55), and I can't be counted on to always retain a firm grip on my equipment, either.

• Cellphone and tablet cameras: Of course, no book on digital photography today would be complete without mentioning the cameras built into these multipurpose devices. But let's be honest: Taking a photo with a tablet — even a small one such as the iPad mini — is cumbersome at best. For the purposes of this book, I concentrate on cellphone cameras.

  Providing many specifics, though, is difficult because the capabilities of cellphone cameras vary so widely. On some phones, you can do things such as tap the screen to indicate the focus point or adjust exposure slightly. Other phones give you no control at all. Suffice it to say that if you're going to use a phone as your main camera, do your research.

Also note that even though you can't swap out lenses on these types of cameras, you can often attach lens modifiers that provide a different angle of view than the built-in lens. Companies such as Moment (www.momentlens.co) sell telephoto and macro (close-up) add-on lenses for smartphones, for example.

Resolution: How many megapixels?

Digital images are made of colored tiles know as pixels. The magnified portion of Figure 1-6 gives you a look at these image building blocks. Camera resolution, stated in megapixels (1 million pixels), indicates the maximum number of pixels that it can use to create a photo.

Chapter 4 discusses resolution in detail, but in terms of evaluating a camera, you need to know these key points:

• Image resolution determines the size at which you can produce high-quality prints. A general guideline is to aim for 300 pixels per linear inch (ppi). Table 1-1 does the math for you, listing the number of megapixels required for traditional print sizes.
• For onscreen photos, you need very few pixels. Resolution affects the display size of digital photos, but does not affect picture quality. And because most screen devices are limited in the number of pixels they can display, a 1 mp image is usually more than adequate. On Facebook, for example, the area allotted for a cover photo (the wide image that runs across the top of the page) is 851 x 315 pixels (about .2 mp).
• High-resolution pictures create larger data files. The more pixels, the faster you fill a camera memory card (the removable storage used by most cameras), a cellphone's onboard storage space, and your computer's hard drive or any online storage closet you may use.

Image sensor: Full frame or smaller?

A photograph is formed when light passes through a lens and strikes a light-sensitive recording medium. In a film camera, the film negative performs the light-recording function. In a digital camera, the image sensor handles the task. The sensor is covered with photosites, which are electronic doodads (that's the technical term) that collect the light data needed to create the image pixels.

Digital-camera image sensors come in two flavors: CCD (charge-coupled device) and CMOS (complementary metal-oxide semiconductor). In the past, each had a reputation for offering different advantages, but today, both are capable of producing excellent images (although techno-geeks still love to argue about which technology is best).

Sensor size, however, is a different story: A smaller sensor usually produces lower image quality than a large sensor. Why? Because when you cram tons of photosites onto a small sensor, you increase the chances of electronic noise that can degrade the picture.

The three largest sensors commonly used in digital cameras have been assigned these monikers:

• Full frame: The sensor is the same size as a 35mm film negative (36 x 24mm). Why full frame? The term is related to camera lenses, which are still manufactured using the 35mm film negative as a standard. That means that a full-frame sensor is large enough to capture the entire angle of view that a lens produces on a 35mm film camera. Smaller sensors can capture only a portion of that angle of view. For more on this issue, check out the upcoming section related to lens focal length.

• APS-C (advanced photo system-type C): This is a smaller-than-full frame sensor but with the same 3:2 proportions as a 35mm negative. Within this category, the specific dimensions of the sensor vary from camera to camera. Nikon APS-C sensors measure about 24 x 16mm, for example, whereas Canon's are approximately 22 x 15mm.

  Some people use the term crop sensor to refer to this category because it's a trimmed-down version of a full-frame sensor. Technically, the C in APS-C stands for classic, but crop is more helpful in remembering how these sensors vary from full-frame versions. Also, Nikon coined the term DX to refer to its APS-C sensors, using FX to indicate full-frame sensors.

• Micro Four Thirds: These sensors are slightly smaller than APS-C sensors, and as the name implies, they have a 4:3 aspect ratio as opposed to the 3:2 ratio of full-frame and APS-C sensors. Note that the term Four Thirds is used for any sensor that has a 4:3 aspect ratio, even for those much smaller than a Micro Four Thirds sensor.

  Which is best — 4:3 or 3:2? Well, there's no magic to either aspect ratio. But 3:2 originals translate perfectly to a 4 x 6 print, and a 4:3 image must be cropped to fit. Mind you, you also need to crop 3:2 originals to print them at other frame sizes — 5 x 7, 8 x 10, and so on. And many cameras enable you to choose from several aspect ratios for your pictures or to crop them to a certain proportion using in-camera editing tools.

If you don't see one of these terms, you can find the sensor's dimensions in the camera's spec sheet. But sometimes, size is presented as a single number, such as 1". In this case, that number reflects the diagonal measure of the sensor, which is the same way that TV sizes are presented.

Image file format: JPEG versus Raw

File format refers to the type of file used to record picture data. The standard format is JPEG (“jay-pegg”), but cameras aimed at intermediate and advanced photographers usually offer a second format called Camera Raw, or just Raw, for short.

When it comes to image quality, Raw outperforms JPEG for reasons you can explore in Chapter 4, if you're interested. (Spoiler: The difference has to do with the fact that JPEG files are compressed to shrink file size, resulting in some data loss.)

Pro shooters also prefer Raw to JPEG because Raw can record a greater dynamic range (spectrum of brightness values, from shadows to highlights). Additionally, JPEG files are “processed” in the camera, with characteristics such as contrast, sharpness, and color saturation tweaked to provide what the manufacturer thinks its clients like. Raw files are just that: uncooked data straight from the image sensor. The photographer then does the work of turning that data into a photo using a software tool known as a Raw converter. This gives the photographer control over the final look of a photo.

This is not to say that you should bypass cameras that offer only JPEG, however. Today's digital cameras produce excellent-quality JPEG images, unlike some of the JPEG-only models of past years. But obviously, a camera that offers both formats beats one that doesn't provide the Raw option. You may not be interested in Raw now, but as your skills grow, it may become more appealing to you.

See Chapter 4 for more details on this important camera setting.

High ISO performance (noise levels)

A digital camera's sensitivity to light is measured in terms of ISO, named for the group that developed the standards for this attribute (International Organization for Standards). Most cameras offer a choice of ISO settings so that you can increase or decrease light sensitivity as needed. In dim lighting, for example, you may need to raise the ISO in order to expose the image.

Being able to increase light sensitivity is great in terms of exposure needs, but there's a tradeoff: As you increase sensitivity, you increase the chances of introducing a defect known as noise, which gives your photo a speckled look. Figure 1-7 offers an example, with the noise most evident in the dark background of the picture. Noise is also easier to spot when you enlarge the image, as illustrated by the magnified view shown on the right in the figure.

Today’s cameras are much less noisy than in years past. In fact, if you're using a camera that's more than a couple of years old, better low-light pictures is a perfectly valid reason to justify the purchase of a new model. But because noise levels vary from camera to camera, this is an important characteristic to study when reading camera reviews. Note, however, that a high ISO isn't the only cause of noise; long exposure times also produce noisy images, no matter what ISO setting you use.

Lens focal length

Focal length, stated in millimeters, refers to the distance from the center of the lens to the image sensor. Focal length is measured when the lens is set to focus at the farthest possible distance.

Having done my due diligence in providing the technical definition of focal length — which, by the way, isn't really important to remember unless you want to impress a roomful of optical engineers — I am now free to explain focal length in real-world photographic terms:

• Focal length determines the angle of view. The shorter the focal length, the more subject area fits in the frame. Increasing focal length narrows the angle of view and makes your subject appear closer and larger. Figure 1-9 illustrates this fact, showing the same scene captured at four focal lengths. (A lower number indicates a shorter focal length.)

  Some focal length recommendations:

  • Landscape photography: Look for a wide-angle lens, characterized by a focal length of 35mm or shorter.
  • Nature and sports photography: Assuming that you'll be shooting at a fair distance from your subject, you need a telephoto lens, which has a focal length of 70mm or longer.
  • Portrait photography: Aim for a focal length in the range of 70-135mm. At other focal lengths, facial features can be distorted. A wide-angle lens, for example, can make your subjects appear sort of like how they look when you view them through a security peephole in a door. And a very long lens can flatten and widen a face.

• The angle of view produced by any focal length depends on the size of the image sensor. You get the stated focal length only on a camera that has a full-frame sensor — that is, one that's the same size as a 35mm film negative. With smaller sensors, the angle of view is reduced because the sensor is no longer large enough to capture the entire area that the lens can see. The resulting picture is what you would get if you took a picture with a full-frame camera and then cropped the picture. The measurement of how much frame area you lose is known as the crop factor.

  Because sensor sizes vary, the crop factor depends on the camera model. Most dSLR and mirrorless image sensors have a crop factor ranging from 1.5 to 2. Figure 1-10 illustrates the image area at these crop factors when compared to the full-frame view.

  To figure out what angle of view a lens will provide, just multiply the camera’s crop factor (which should be stated in the camera specs) by the lens focal length. For example, if the camera has a crop factor of 1.5, a 50mm lens gives you the same angle of view as a 75mm lens on a full-frame digital or 35mm-film camera.

• Focal length affects depth of field. As focal length goes up, depth of field — the distance over which focus appears sharp — goes down. As an example, compare the backgrounds in Figure 1-9. Notice how much blurrier the trunk of the palm tree behind the monument appears in the 100mm image than in the versions shot at the shorter focal lengths.

  What about the crop factor and depth of field? They're unrelated; you get the same depth of field from a particular focal length no matter what the size of the sensor. The image produced by a camera with a smaller sensor may appear to have a different depth of field than one from a camera with a full-frame sensor, but that's only because you're looking at different portions of the scene.

• A prime lens offers a single focal length; a zoom lens, a range of focal lengths. For example, a lens might zoom from 18 to 55mm.

  In camera or lens advertisements, the zoom range is sometimes described in terms of an “x” factor, as in a 3x zoom. Here, the x means times, with the value indicating the difference between the shortest and longest focal length of the lens. So an 18–55mm lens boasts a 3x zoom, for example (18 x 3 = 54).

  As a general rule, prime lenses equate to better-quality photos because a lens can be engineered to optimal performance at only a single focal length. That said, one of my favorite lenses is the super zoom; it has a monster focal length range — 18 to 270mm. Newer lenses perform better in this regard than those manufactured in the past.

• Don't bother with digital zoom. For fixed-lens cameras, note whether the lens offers an optical or digital zoom. Optical zoom is a true zoom lens and produces the best picture quality. Digital zoom is a software feature that crops away the outside of the image and enlarges the remaining area, a process that lowers image quality.

In most cases, the focal length is printed on the lens, but for some models, you may need to check the user manual or lens spec sheet. Often, the manufacturer gives both the actual focal length of the lens (that's the measurement mentioned in the opening to this section) as well as the 35mm equivalent.

As for cellphone cameras, finding the focal length usually requires inspecting the image metadata (hidden data stored with the digital photo file). You may be able to view this data in a photo program; visit Chapter 9 for a list of some programs to consider. For the time being, just know that cellphone cameras typically have wide-angle lenses.

Lens aperture range

The aperture is an adjustable hole through which light must pass to reach the image sensor. Aperture size is stated in f-numbers, more commonly referred to as f-stops. A higher number indicates a narrower aperture size. So f/11, for example, results in a smaller aperture opening than f/8.

Changing the aperture size is one way to manipulate exposure. But the f-stop setting also contributes to depth of field, or the distance over which focus appears sharp. The smaller the aperture, the greater the depth of field, as illustrated in Figure 1-11.

If you're keeping track, you now know that the lens gives you two points of control over depth of field: the focal length and the aperture setting. In Figure 1-11, I used the same focal length for each shot, so the aperture setting is the sole reason for the shift in depth of field.

And why, you're probably wondering, is the exposure of both images in Figure 1-11 the same, given what I just said about the f-stop affecting image brightness? This is why: When I opened the aperture, I also reduced the exposure time, so the light was able to strike the image sensor for a shorter period. I kept the light sensitivity (ISO setting) the same for both photos.

You can explore f-stops, exposure, and depth of field further in Part 2 of the book. For the purpose of comparing lenses, you need just a few more bits of aperture information:

• Every lens has a specific range of aperture settings. Obviously, the larger that range, the more control you have as a photographer.

• The larger the maximum aperture, the “faster” the lens. Again, the more open the aperture becomes, the less time is needed to expose the image. So if one lens can open to a maximum setting of f/4 and another lens has a maximum aperture of f/2, the f/2 version is said to be faster.

  A fast lens is especially beneficial when photographing action, because a moving subject blurs at long exposure times. But it also helps when you shoot in dim lighting, because you can get the shot at a lower ISO setting, reducing the chances of image noise.

• On a zoom lens, the aperture range may change as you zoom in or out. For example, on an 18–140mm lens, you may be able to open the aperture to f/2 when the lens is at the 18mm position but only to f/5.6 at 140mm.

  You can buy zoom lenses that maintain the same minimum and maximum apertures throughout the zoom range, but be prepared to part with more money than for a lens that doesn't offer this feature.

• Depth of field at any aperture varies depending on the size of the image sensor and lens. Cameras with small sensors and lenses produce a much greater depth of field at any f-stop than cameras with larger sensors and lenses. The result is that it can be difficult to achieve much background blurring even if you open the aperture all the way. That's an important consideration if you're interested in the type of photography that benefits from a short depth of field, such as portraiture. On the other hand, if you're a landscape photographer, you may love the extended depth of field those smaller cameras produce.

Viewfinder: Optical or electronic?

Cellphones and cameras that lack a viewfinder force you to frame your shots using the monitor. That causes two problems: You have to hold the camera a few inches away to see the monitor, and unless you keep your hands very steady, camera shake can cause a blurry picture. Additionally, monitors wash out in bright light, making it hard to see what you’re shooting. For these reasons, I consider a viewfinder an important bonus. But not all viewfinders work the same way, and because this component plays a critical role in your camera use, it's worth understanding the differences.

Here's a look at your options:

• Optical viewfinders: This term is used to describe a standard viewfinder — the kind that's been used for a long time in both film and digital cameras. Made from glass, optical viewfinders come in two forms:

  • Mirror-and-pentaprism (dSLR) viewfinders: In a dSLR, a tiny mirror sits in front of the shutter, the barrier that prevents light from hitting the image sensor until you press the shutter button. The mirror reflects the light coming through the lens onto a pentaprism, which is a multi-angled mirror that flips the reflected image to its proper orientation and then bounces it to the viewfinder. When you press the shutter button, the mirror flips up, the shutter opens, and the light passes through the lens to the film or sensor. The mirror flips down after the shutter closes.

    This type of viewfinder is categorized as a through-the-lens, or TTL, viewfinder because the display is created by light coming directly through the lens.

  • Non-TTL (through-the-lens) viewfinders: The problem with the mirror-and-pentaprism approach used by dSLR cameras is that the assembly that makes it possible adds to the size and weight of the camera. Rangefinders and most point-and-shoot cameras instead use a different setup: The viewfinder is set above and to the side of the lens.

    The disadvantage to this viewfinder setup is that it results in parallax error. Because the viewfinder and lens have slightly different angles on the world, the viewfinder doesn't show exactly what the lens will capture, making it difficult to precisely frame a photo. To help solve the problem, most cameras include framing marks in the viewfinder to guide you; when camera shopping, be sure the framing marks are easily visible. And note that not all viewfinders of this type are created equal — the amount of parallax error varies from camera to camera, so do your research.

• Electronic viewfinder (EVF): In the past few years, manufacturers found another way around both the parallax problem and the bulky design of the dSLR-style viewfinder by developing electronic viewfinders. Mirrorless interchangeable-lens cameras and some point-and-shoot compacts use this type of viewfinder.

  With an electronic viewfinder (EVF), the camera sends the live feed that's normally displayed on the camera monitor to the viewfinder, and because the monitor shows the same area as the lens, this viewfinder option offers the same improvement in accuracy that you get with the dSLR system. But this system has two other benefits: First, you can not only use the viewfinder to compose your subject, but you can also see everything normally displayed on the camera monitor. You can review your photos through the viewfinder, for example, and see camera menus. I love these features when I'm shooting in bright sunlight — instead of having to look for a shady spot where I can clearly see what the monitor is displaying, I simply look at the viewfinder display.

  However, EVF displays vary in quality, so this is one component you should test in person. Some are amazingly crisp, looking like a high-def TV display, and others are grainy and blurry, making it difficult to compose your pictures precisely. Also, keep in mind that you usually can’t see anything through the viewfinder until you turn on the camera, which means that you can’t set up your shots without using up battery life. More importantly, most electronic viewfinders go dark for a split second between shots, which makes it difficult to follow the action when you're shooting a burst of continuous frames.

While we're on the subject of viewfinders, make sure that you can easily make out the data displayed in the viewfinder. Especially for people who wear glasses, the readouts in some viewfinder displays are too small and dim to be easily read. You also want a viewfinder that can be adjusted to your eyesight; the control in question is called a diopter adjustment.

Video-recording capabilities

Most digital cameras can record video as well as still pictures. In this book, I don't provide much video-recording information, for a few reasons: First, if all you're after is basic recording, there's not much to it: You press the Record button to start recording and press it again to stop. On the other hand, if you want to get serious about digital cinematography, you're probably after a lot more information than I have room to offer in this book.

That said, I realize that you may want a little guidance as far as knowing which video-related specs are most important, so the following sections provide a quick rundown. You can find lots of information online; one site to get you started is www.dslrvideoshooter.com. Also check your camera manufacturer's website; many offer whole sections devoted to video recording.

Memory-card features

Instead of recording images on film, digital cameras store picture data on removable memory cards. Most cameras can hold only one card at a time, but a few, like the model shown in Figure 1-15, have two card slots. This feature is great because you can configure the two cards to perform different storage functions. You can put all your Raw files on one card, for example, and JPEG files on the other. Or you can send all files to both cards so that if one fails, the other provides a safety net.

As for card type, most cameras use either SD (Secure Digital) or CF (CompactFlash) cards, which you can see peeking out of the front and back card slots in Figure 1-15. Some high-end pro cameras accept new card types, XQD and CFast, both of which are designed for high-resolution, high-speed shooters. Some cellphones and tablets enable you to store files on a Micro SD card, which is a miniature version of an SD card.

Although I would never choose a camera based on what type of card it uses, it is important to know what card speed the camera supports. A model that supports high-speed cards can write picture data to the card more quickly, enabling you to capture more frames per second and record smoother videos. Also note that some features provided on the latest cameras aren't compatible with old, slow cards.

Manufacturers use a variety of terms to specify card speed, and those terms vary depending on the type of card. Rather than bore you with an explanation of all the various speed specs, I'll keep it simple: A higher number means faster performance. Check your camera manual to find out which speeds it supports, and then buy the fastest card your budget allows. (Yes, prices go up along with speed.) Memory cards also vary in capacity; again, check your camera manual to find out how large of a card it can accept. If you're using an older camera, it may not be able to use today's super-capacity cards.

Convenience features

No matter what category of photographer you consider yourself, I rank the following features as not critical, but nice to have:

• Articulating (adjustable) monitor: Some cameras, such as the Canon model shown in Figure 1-16, feature fold-out screens that can be rotated to a variety of angles. The benefit is that you can position the camera at nearly any angle while still being able to see the monitor. When not using the monitor, you can rotate it so that the screen faces the back of the camera, providing an extra degree of monitor protection.
• Touchscreen operation: Of course, all smartphone cameras can be operated by touch, as can the phone's picture-playback tools. But touchscreens are being included on many other types of digital cameras as well. I originally thought touchscreens were a gimmick not worth the additional cost they add to a camera, but having used them for a while, I've changed my tune. They do make many camera operations easier, especially scrolling through pictures in playback mode and selecting options from menus.

• Remote control shutter release: Being able to trigger your camera's shutter release with either a wired or wireless remote control comes in handy for a couple reasons. You can secure a camera on a tripod near your hummingbird feeder, for example, and then step away to avoid spooking any birds that come by, triggering the shutter release from afar. Remote control functionality also is great for long-exposure shots because you don't have to physically press the camera's shutter button, which can jog the camera just enough to introduce a slight blur.

  Some cameras enable you to use a smartphone or tablet to trigger the shutter release. For more about remote controls, visit Chapter 10.

• Wireless connectivity: If you buy a camera that offers wireless connectivity, you can enjoy the cable-free life when it's time to download pictures or share them online. Some models are designed to connect to a standard wireless network (such as one you may have set up to allow everyone in the house to access your Internet connection). Others offer NFC (Near Field Communication), which means that you can set the camera next to another NFC-enabled device, such as a tablet, and the two can connect on their own independent wireless channel. For more about this feature, see Chapter 9.
• In-camera editing tools: Many cameras offer built-in retouching filters that can fix minor picture flaws, such as red-eye or exposure problems. For easier online sharing, you also may find in-camera options that create low-resolution copies of high-res originals and convert Raw files into the JPEG format. (You have to convert Raw files to JPEG in order to share them online.) These tools are especially helpful for times when you need to print or share a photo before you can get to your computer to fix the image in your photo software or create an online version.
• GPS tagging: Have a hard time remembering — or proving — where you've been? Some cameras offer built-in GPS (global positioning satellite) technology that can tag your pictures with the location where you shot them.
• Video-out capabilities: If the camera has a video-out port, you can connect the camera to a television and view your pictures on a TV screen. Some cameras offer both standard-definition and high-definition (HDTV) output; you may need to buy the necessary cables, however.