LITMIR.BIZ

      Professional dSLRs that range from $1,500 to $2,500 have performance and form factor compromises that keep them relatively affordable. Ultra-high-end professional dSLRs run between $2,500 and $7,000. For example, the Canon EOS-1D X Mark II body lists for approximately $6,000 and the Nikon D5 body lists for almost $6,500. These cameras represent the pinnacle of a company's dSLR lineup. They have the best sensors, image processors, autofocus and metering systems, best ISO performance, and have a whole host of other premier features. Simply put, they are the best cameras you can buy in the 35mm equivalent digital SLR format.

Delving into Camera Specifications

      Camera specifications (informally called specs) are details that describe a camera’s features and capabilities. Companies put this information on their websites and in the camera manual. Specifications can be technical, but this isn’t rocket science. Knowing a few basics will help you understand what each camera is capable of, and you’ll be able to compare models against each other.

       Basic information

      I’ve already covered specifications like the camera name, pixel count, sensor size, and so forth, so I won’t duplicate that here. If you need to review, flip back to the “Naming and Classifying Digital SLRs” section, earlier in this chapter.

       Crop factor

When you look at camera listings and specifications you will quickly run across the term crop factor. As described earlier, crop factor is related to sensor size. Here’s why it’s important: Identical 50mm lenses will produce different photos when mounted on full-frame cameras versus cropped dSLRs. Why? Because the larger image sensor on the full-frame camera captures more of the scene than the smaller sensor on the cropped-frame camera. The smaller sensor captures a “cropped” area by comparison. By how much? By the amount of the crop factor. Figure 1-9 shows how much less a cropped-frame image sensor captures than a full-frame dSLR. It’s important to note that this does not make cropped-frame cameras worthless. Quite the contrary. In fact, having larger pixel counts than ever before has enabled newer cropped-frame dSLRs to compete more effectively. They are able to capture much more detail than they used to.

       FIGURE 1-9: Smaller image sensors crop the scene by the amount of the crop factor.

       Knowing the crop factor gives you the ability to compare lenses mounted on cameras that have different sensor sizes and the photos they capture. Multiply the focal length of the lens by the camera’s crop factor to get the 35mm equivalent focal length. You’re able to compare mangos to mangos using 35mm equivalent focal lengths.

       ISO

ISO, also called ISO speed or ISO sensitivity, is a measure of the image sensor’s sensitivity to light. The camera specification will list an ISO range. This range will begin at 50 or 100 and increase to something like 12800 or 16000, sometimes vastly more. See Book 3, Chapter 4 for more information on ISO. I am setting the ISO speed in Figure 1-10 to 3200, well below the maximum of 16000.

       FIGURE 1-10: Setting the ISO.

       Higher ISOs improve your ability to shoot in low light and let you choose faster shutter speeds when capturing action. The downside to higher ISO is increased noise, especially in consumer cameras.

       Shutter speeds

There are three shutter speeds that are listed in a camera’s specifications: the fastest, slowest, and the flash sync speed (the fastest shutter speed you can use and still fire the built-in flash). The fastest shutter speeds in use today range from 1/4000 second for consumer dSLRs to 1/6000 or 1/8000 second for more advanced models (see Figure 1-11). The slowest shutter speed you can typically set is 30 seconds.

       FIGURE 1-11: This camera has a maximum shutter speed of 1/8000 second.

      Consumer dSLRs have sync speeds from 1/160 to 1/200 second while more expensive models are a bit faster (1/250 second). Faster shutter speeds are possible with an external flash and a feature called high-speed sync. I talk more about that in Book 4, Chapter 3.

OTHER SPECS

      There are a number of other camera specifications that are not listed here because, frankly, they are either the same for most cameras or irrelevant to most photographers. This includes color spaces, release modes, file formats, white balance, and so forth. They may be interesting, but not the best way to decide what camera to buy. Generally speaking, you’ve decided on a camera before the point where things like metering technology make a difference.

       Autofocus system

The autofocus system is another area where you can compare cameras. Each camera has a number of autofocus (AF) points and AF area selection modes. Cameras use AF points to automatically focus on subjects. Having several points spread over a large area gives you a greater chance of having an AF point where you need it. AF area selection modes enable you to choose how the camera decides which points to use. You can have the camera decide, or choose to manually select an individual point for greater precision. You can also choose a group of points, often called a Zone, to lock onto and track action, as shown in Figure 1-12.

       FIGURE 1-12: This camera has four AF point selection modes.

      Here are a few examples: The entry-level Canon T6 has 9 AF points located in the central region of the viewfinder. The similarly priced Nikon D3300 has 11 AF points, which cover the same basic area. More expensive cameras will have more AF points and a larger number of selection options. The Canon 80D and Nikon D7200, for example, have 45 and 51 AF points respectively, spread over a wide area.

       Movies

All current dSLRs shoot movies (Figure 1-13 shows this in action). Full HD video is the standard format. Most cameras also have an HD option, which is smaller than Full HD. Support for older VGA is diminishing. 4K video is emerging. Here are their sizes:

      ❯❯ Full HD movies (including Sony AVCHD) are 1920 x 1080 pixels.

      ❯❯

Скачать книгу