AvQD

Metering mode Highlight Tone Priority

Figure 4-13: This row contains additional exposure information.

• Exposure mode: This symbol indicates which of the camera's exposure modes you used — Full Auto, Av (aperture-priority autoexposure), Portrait, and so on. The symbols mirror what you see on the camera Mode dial. You can find details about all the modes in Chapters 2 and 5.

• Metering mode: This symbol represents the metering mode, which determines which part of the frame the camera uses when calculating exposure. Chapter 5 explains.

• Flash Compensation amount: Here you can see whether you adjusted flash power using the Flash Compensation feature, detailed in Chapter 5.

• ISO speed: Chapter 5 also explains this option, which controls the light sensitivity of the camera's image sensor.

• Highlight Tone Priority: If you enabled this exposure feature for the shot, you see the little D+ symbol. See Chapter 5 to find out how Highlight Tone Priority affects your photos.

✓ Row 3 data: Information on this row of the display, labeled in Figure 4-14, mostly relates to color settings. Here's the scoop:

White Balance correction

White balance

White Balance correction

White balance

Picture Style

Figure 4-14: Look to this row for details about advanced color settings.

Picture Style

Figure 4-14: Look to this row for details about advanced color settings.

• White Balance setting: Chapter 6 has details on this option, which helps ensure accurate photo colors. The setting shown in the figure, AWB, stands for Auto White Balance. See the table in Chapter 6 for a look at the symbols representing other White Balance settings.

• White Balance correction: This collection of data tells you whether you applied any adjustment to the White Balance setting you used. Chapter 6 explains this advanced color option.

• Picture Style: Notice that the symbol shown here looks similar to the one on the bottom cross key on the camera back. You can use that cross key to access Picture Styles, which enable you to tweak image color, contrast, and sharpness. In the playback display, you see the same symbol plus a letter that indicates the Picture Style you used for the photo. The S in Figure 4-14 represents the Standard Picture Style, for example. The values to the right relate to four characteristics that you can adjust for each Picture Style. Chapter 6 explains how each Picture Style affects your image.

✓ Row 4 data: Shown at the top of Figure 4-15, this row tells you the following tidbits of information:

• Quality and file size: For details on the Quality setting and its affect on file size and picture quality, see Chapter 3. File size is shown in megabytes (MB).

Quality File size

Original decision data

Color space

Quality File size

Original decision data

Color space

Image number/

Date/time total images

Figure 4-15: The bottom two rows of the display offer this data.

Image number/

Date/time total images

Figure 4-15: The bottom two rows of the display offer this data.

• Original Decision Data: The Rebel T1i/500D enables you to tag an image file with a code that indicates that the image is original — meaning that it hasn't been altered in a photo program or otherwise tampered with after it was captured. To check the code, you need a separate product called the Original Data Verification Kit, which retails for about $700, unfortunately. If you do enable the feature on the camera, which I explain how to do in Chapter 11, a lock icon appears in this area of the playback screen.

• Color space: Your camera can capture images in two color spaces, sRGB and Adobe RGB. A color space is a definition of the spectrum of colors that an image can contain. You can change color spaces only in advanced exposure modes; Chapter 6 has details about how and why to do so.

✓ Row 5 data: Wrapping up the smorgasbord of shooting data, the bottom row of the playback screen holds two more pieces of information, as shown in Figure 4-15:

• Image number/total images recorded: Again, this pair of numbers indicates the current image number with respect to the total number of images on the current memory card.

• Date and time: These values show you the exact moment that the image was recorded. Of course, you must first set the camera date and time, as Chapter 1 explains.

One note about Figures 4-12 through 4-15: I included all possible symbols, values, and other shooting data just for the purposes of illustration. If any of the data items don't appear on your monitor, it simply means that the feature wasn't enabled when you captured the photo.

Understanding Histogram display mode

A variation of the Shooting Information display, Histogram display offers the data you see in Figure 4-16. Again, you get the thumbnail view of your image, but this time some of the extensive shooting data is replaced by a second histogram.

The next two sections explain what information you can glean from the histograms. See the preceding sections for a map to the other shooting data on the screen.

As with the Shooting Information display, this one is only available when you're viewing photos one at a time. If your monitor is showing four or nine thumbnails, press the AF Point Selection button to get to full-frame view. Then press DISP as needed to get to the Histogram display.

RGB Histogram

16/38

Figure 4-16: Histogram display mode replaces some shooting data with an RGB histogram.

xflBE*

xflBE*

Interpreting a brightness histogram

One of the most difficult photo problems to correct in a photo-editing program is known as blown highlights in some circles and clipped highlights in others. In plain English, both terms mean that highlights — the brightest areas of the image — are so overexposed that areas that should include a variety of light shades are instead totally white. For example, in a cloud image, pixels that should be light to very light gray become white because of overexposure, resulting in a loss of detail in those clouds.

In Shooting Information display mode, areas that fall into this category blink in the image thumbnail. This warning is a great feature because simply viewing the image on the camera monitor isn't always a reliable way to gauge exposure. The relative brightness of the monitor and the ambient light in which you view it affect the appearance of the image onscreen.

For a detailed analysis of the image exposure, check the Brightness histogram, which is a little graph that indicates the distribution of shadows, highlights, and midtones (areas of medium brightness) in your image, as shown in Figure 4-17. Photographers use the term tonal range to describe this aspect of their pictures. The Brightness histogram appears to the right of the image thumbnail in Shooting Information display mode and in the lower-right corner in Histogram display mode.

The horizontal axis of the graph represents the possible picture brightness values, from the darkest shadows on the left to the brightest highlights on the right. And the vertical axis shows you how many pixels fall at a particular brightness value. A spike indicates a heavy concentration of pixels. For example, in Figure 4-17, which shows the histogram for the lily image in Figure 4-16, the histogram indicates a broad range of brightness values, but with the majority of pixels falling between Shadows Highlights medium and maximum brightness. ^_

Keep in mind that there is no one Figure 4-17: The Brightness histogram indicates "perfect" histogram that you should the tonal range of your image. try to achieve. Instead, you need to interpret the histogram with respect to the amount of shadows, highlights, and midtones that comprise your subject. For example, the histogram in Figures 4-16 and 4-17 makes sense for this particular image because the subject contains mostly light colors, with only a few dark ones. Pay attention, however, if you see a very high concentration of pixels at the far right or left end of the histogram, which can indicate a seriously overexposed or underexposed image, respectively.

Less saturated -<-

More saturated -

Figure 4-18: The RGB histogram can indicate problems with color saturation.

Reading an RGB histogram

When you view your images in Histogram display mode, you see two histograms: the Brightness histogram, covered in the preceding section, and an RGB histogram, shown in Figure 4-18.

To make sense of the RGB histogram, you first need to know that digital images are called RGB images because they are created out of three primary colors of light: red, green, and blue. The RGB histogram shows you the brightness values for each of those primary colors.

By checking the brightness levels of the individual color components, sometimes referred to as color channels, you can assess the picture's

Less saturated -<-

More saturated -

Figure 4-18: The RGB histogram can indicate problems with color saturation.

color saturation levels. If most of the pixels for one or more channels are clustered toward the right end of the histogram, colors may be over-saturated, which destroys detail. On the flip side, a heavy concentration of pixels at the left end of the histogram indicates an image that may be undersaturated.

A savvy RGB histogram reader can also spot color balance issues by looking at the pixel values. But frankly, color balance problems are fairly easy to notice just by looking at the image on the camera monitor. And understanding how to translate the histogram data for this purpose requires more knowledge about RGB color theory than I have room to present in this book.

If you are a fan of RGB histograms, however, you may be interested in another possibility: You can swap the standard Brightness histogram that appears in Shooting Information playback mode with the RGB histogram. Just visit Playback Menu 2, highlight the Histogram option, as shown on the left in Figure 4-19, and press the Set button to display the right screen in the figure. Select RGB instead of Brightness and press the Set button again.

Figure 4-19: You can change the histogram type that appears in Shooting Information display mode.

Figure 4-19: You can change the histogram type that appears in Shooting Information display mode.

For information about manipulating color, see Chapter 6.

Digital Photography Mastery

Digital Photography Mastery

Insider Secrets Revealed By the Pro Showing You How to Become a Professional Photographer! Discover The Secret Tips & Techniques On How To Be A Professional Photographer, Start Producing High Quality Pictures and Skyrocket Your Photography Business Income Revenue To The Roof TODAY! You're About to Discover the Powerful Strategies and Method to Start Taking Sharp, Clear and High Quality Pictures Like the Professional Photographer Without Paying a Single Penny to the Expert!

Get My Free Ebook


Post a comment