JPEG The imaging and Web standard

Pronounced jay-peg, this format is the default setting on your camera, as it is for most digital cameras. JPEG is popular for two main reasons:

✓ Immediate usability: JPEG is a longtime standard format for digital photos. All Web browsers and e-mail programs can display JPEG files, so you can share them online immediately after you shoot them. You also can get JPEG photos printed at any retail outlet, whether it's an online or local printer. Additionally, any program that has photo capabilities, from photo-editing programs to word-processing programs, can handle your files.

✓ Small files: JPEG files are smaller than Raw files. And smaller files means that your pictures consume less room on your camera memory card and in your computer's storage tank.

The downside — you knew there had to be one — is that JPEG creates smaller files by applying lossy compression. This process actually throws away some image data. Too much compression leads to the defects you see in the JPEG Artifacts example in Figure 3-1, near the start of this chapter.

On your camera, the amount of compression that is applied depends on whether you choose a Quality setting that carries the label Fine or Normal. The difference between the two breaks down as follows:

✓ Fine: At this setting, represented by the symbol you see in the margin, very little compression is applied, so you shouldn't see many compression artifacts, if any.

✓ Normal: Switch to Normal, and the compression amount rises, as does the chance of seeing some artifacting. Notice the jaggedy-ness of the Normal icon, shown in the margin? That's your reminder that all may not be "smooth" sailing when you choose a Normal setting.

Note, though, that even the Normal setting doesn't result in anywhere near the level of artifacting that you see in my example in Figure 3-1. Again, that example is exaggerated to help you recognize artifacting defects and understand how they differ from other image-quality issues.

In fact, if you keep your image print or display size small, you aren't likely to notice a great deal of quality difference between the Fine and Normal compression levels. The differences become apparent only when you greatly enlarge a photo.

Take a look at Figure 3-7, for example, which shows the same subject captured at the Large/Fine and Large/Normal settings, along with the respective file sizes that each option produces. I captured each image at the same resolution so that file type is the only variable. To my eye, at least, there's no clear-cut difference in quality when the photos are printed at this size. However, in Figure 3-8, which shows a greatly enlarged view of a portion of one of the playing cards — the red K from the King of Hearts card — you can detect the impact of the greater compression level applied at the Normal setting.

Understand something important about these examples: At this magnification, you can see some pixelation as well as some compression artifacts. The ragged edge of the letter K is because of pixelation, so that aspect of the photo is the same for both the Normal and Fine examples. The splotchiness between the edges of the letter as well as in the white background is the compression defect. And here, the Fine example exhibits less of that particular defect than the Normal example.

Large/Fine, 5.0MB Large/Normal, 2.5MB

Large/Fine, 5.0MB Large/Normal, 2.5MB

Canon 1000d Jpeg Raw Quality
Figure 3-7: When the print or display size is small, detecting any difference in quality between the Fine and Normal examples is difficult.
Canon 1000d Jpeg Raw Quality

Given that the differences between Fine and Normal aren't all that easy to spot until you really enlarge the photo, is it okay to shift to Normal and enjoy the benefits of smaller files? Well, only you can decide what level of quality your pictures demand. For me, the added file sizes produced by the Fine setting aren't a huge concern, given that the prices of memory cards are so low right now that it's easy to stock up on as many as I need. Long-term storage is more of an issue; the larger your files, the faster you fill your computer's hard drive and the more DVDs or CDs you need for archiving purposes. But in the end, I'm willing to take the storage hit in exchange for the lower compression level of the Fine setting. You never know when a casual snapshot is going to be so great that you want to print or display it large enough that even minor quality loss becomes a concern. And of all the defects that you can correct in a photo editor, artifacting is one of the hardest to remove. So I stick with Fine if I shoot in the JPEG format.

I suggest that you do your own test shots, however, carefully inspect the results in your photo editor, and make your own judgment about what level of artifacting you can accept. Artifacting is often much easier to spot when you view images onscreen. It's difficult to reproduce artifacting here in print because the print process obscures some of the tiny defects caused by compression.

If you don't want any risk of artifacting, bypass JPEG altogether and change the file type to Raw (CR2). Or consider your other option, which is to record two versions of each file, one Raw and one JPEG. The next section offers details.

^\NG/ Whichever format you select, be aware of one more important rule for preserving the original image quality: If you retouch pictures in your photo software, don't save the altered images in the JPEG format. Every time you alter and save an image in the JPEG format, you apply another round of lossy compression. And with enough editing, saving, and compressing, you can eventually get to the level of image degradation shown in the JPEG example in Figure 3-1, at the start of this chapter. (Simply opening and closing the file does no harm.)

Always save your edited photos in a nondestructive format. TIFF, pronounced tiff, is a good choice and is a file-saving option available in most photo-editing programs. Should you want to share the edited image online, create a JPEG copy of the TIFF file when you finish making all your changes. That way, you always retain one copy of the photo at the original quality captured by the camera. You can read more about TIFF in Chapter 8, in the section related to processing Raw images. Chapter 9 explains how to create a JPEG copy of a photo for online sharing.

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