Displaying Histograms

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To view histograms on your screen, press the DISP button while an image is shown on the LCD. Keep pressing the button until the histogram(s) are shown. The display will cycle between several levels of information, including flashing highlights and two histograms. One histogram shows overall brightness levels (Figure 4.24), while the second type of histogram screen shows both brightness levels and levels for each of the red, green, and blue channels (see Figure 4.25). During histogram display, you'll also see a thumbnail at the left side of the screen with your image displayed. Overexposed areas will blink, which is your prompt to use negative exposure compensation if you want to salvage those areas. (See "Making EV Changes" above.) To change your default histogram type from Brightness to RGB, use the Histogram setting in the Playback 2 menu.

Canon Histogram

A brightness histogram shows the relationship of tones in an image.

Figure 4.25

Individual red, green, and blue histograms show the exposure for each color channel.

Figure 4.25

Individual red, green, and blue histograms show the exposure for each color channel.

A typical histogram produces a mountain-like shape, with most of the pixels bunched in the middle tones, with fewer pixels at the dark and light ends of the scale. Ideally, though, there will be at least some pixels at either extreme, so that your image has both a true black and a true white representing some details. Learn to spot histograms that represent over- and underexposure, and add or subtract exposure using an EV modification to compensate.

For example, Figure 4.26 shows the histogram for an image that is badly underexposed. You can guess from the shape of the histogram that many of the dark tones to the left of the graph have been clipped off. There's plenty of room on the right side for additional pixels to reside without having them become overexposed. Or, a histogram might look like Figure 4.27, which is overexposed. In either case, you can increase or decrease the exposure (either by changing the f/stop or shutter speed in manual mode or by adding or subtracting an EV value in autoexposure mode) to produce the corrected histogram shown in Figure 4.28, in which the tones "approach" the right side of the histogram to produce as many highlight details as possible. Again, see "Making EV Changes," above for information on dialing in exposure compensation.

Figure 4.26 This histogram Figure 4.27 This histogram reveals Figure 4.28 A histogram for a shows an underexposed image. that the image is overexposed. properly exposed image should look like this.

Figure 4.26 This histogram Figure 4.27 This histogram reveals Figure 4.28 A histogram for a shows an underexposed image. that the image is overexposed. properly exposed image should look like this.

The histogram can also be used to aid in fixing the contrast of an image, although gauging incorrect contrast is more difficult. For example, if the histogram shows all the tones bunched up in one place in the image, the photo will be low in contrast. If the tones are spread out more or less evenly, the image is probably high in contrast. In either case, your best bet may be to switch to RAW (if you're not already using that format) so you can adjust contrast in post processing. However, you can also change to a user-defined Picture Style (User Def 1, User Def 2, or User Def 3 in the Picture Style menu) with contrast set lower ( —1 to —4) or higher (+1 to +4) as required.

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  • fabrizio
    How to access a histogram in canon t2i?
    8 years ago
  • john
    How to get the histogram on screen canon t2i?
    8 years ago
  • Sancho
    How to switch on histogram in eos t2i?
    3 years ago
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    How to turn off histogram on canon camera EOS 550D?
    3 years ago
  • darryl
    How to read a bar graph canon 550d tutorial?
    2 years ago
  • Jarno
    Can canon t2i display image on lcd?
    2 years ago
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    How to display the histogram on canon 550d?
    2 years ago
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    How to understand canon 550d?
    2 years ago
  • heikki
    Does the canon t2i have live histsgram?
    2 years ago
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    How to show histogram on canon camera?
    1 year ago
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    How to view histogram canon7D?
    1 year ago
  • Eulalia
    How to view histogram on a EOS Rebel T2i?
    8 months ago
  • KIBRA
    How to check histogram on canon rebel?
    7 months ago
  • andrea furst
    How to turn histogram off in canon 1200?
    6 months ago
  • Ruairi Davidson
    What is a histagran on a t6s camera?
    5 months ago
  • curtis
    How to show histogram on eos650d?
    4 months ago
  • ANNE
    How to show light bars on canon t2i?
    2 months ago
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    How to turn on histogram canon rebel t5?
    3 days ago

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