Fixing Exposures with Histograms

128 David Busch’s Nikon D7000 Guide to Digital SLR Photography

up with a finished image that has the extended dynamic range you’re looking for. (This concludes the image editing portion of the chapter. We now return you to our alternate sponsor: photography.)

Fixing Exposures with Histograms

While you can often recover poorly exposed photos in your image editor, your best bet is to arrive at the correct exposure in the camera, minimizing the tweaks that you have to make in post-processing. However, you can’t always judge exposure just by viewing the image on your D7000’s LCD after the shot is made. Nor can you get a 100 percent accurately exposed picture by using the D7000’s Live View feature. Ambient light may make the LCD difficult to see, and the brightness level you’ve set can affect the appear- ance of the playback image.

Instead, you can use a histogram, which is a chart displayed on the D7000’s LCD that shows the number of tones being captured at each brightness level. You can use the infor- mation to provide correction for the next shot you take. The D7000 offers four his- togram variations in three screens: three histograms that show overall brightness levels for an image and an alternate version that separates the red, green, and blue channels of your image into separate histograms.

DISPLAYING HISTOGRAMS

To view all the available histograms on your screen, you must have the D7000 set up properly. First, you’ll need to mark Histograms using the Display Mode entry in the Playback menu, as described in Chapter 8. That will make the Histograms screen visible when you cycle among the informational screens while pressing the multi selector up/down buttons while an image is displayed.

The most basic histogram is displayed during playback when you press the multi selec- tor up/down buttons to produce the Overview Data screen, as described briefly in Chapter 3, and shown in Figure 3.24. This screen provides a small histogram at the right side that displays the distribution of luminance or brightness. The most useful histogram screen is the one shown in Figure 4.19, which displays both a luminance chart and sep- arate red, green, and blue charts.

Both luminance and RGB histograms are charts that include a representation of up to 256 vertical lines on a horizontal axis that show the number of pixels in the image at each brightness level, from 0 (black) on the left side to 255 (white) on the right. (The three-inch LCD doesn’t have enough pixels to show each and every one of the 256 lines, but, instead provides a representation of the shape of the curve formed.) The more

D7000 specifications

The Nikon D7000 is a mid-range digital single-lens reflex (DSLR) camera that has garnered a reputation for its impressive blend of features and user-friendly design. Released in 2010, the D7000 marked a significant step forward for Nikon, appealing to both amateur photographers and enthusiasts seeking a robust and versatile camera.

At the heart of the D7000 is a 16.2-megapixel APS-C (DX) CMOS sensor that delivers sharp, high-resolution images with rich colors and stunning detail. Coupled with Nikon's EXPEED 2 image processing engine, the camera excels in low-light performance, allowing photographers to shoot at sensitivities ranging from ISO 100 to ISO 6400, expandable to ISO 25600. This flexibility empowers users to capture clean images even in challenging lighting situations.

The autofocus system of the D7000 is another highlight, featuring a 39-point AF system with nine cross-type sensors. This advanced system ensures fast and accurate focus, making it suitable for a variety of shooting scenarios, from portraits to fast-action sports photography. The camera also includes full HD video recording capabilities at 1080p, with options for frame rates of 24, 25, and 30 frames per second, providing videographers with quality and flexibility.

The D7000's build quality is robust, with a magnesium alloy body designed to withstand the rigors of regular use. It is weather-sealed to protect against dust and moisture, making it a reliable choice for outdoor shooting. The camera features a 3-inch LCD screen with a resolution of 921,000 dots, allowing for high-clarity image review and menu navigation. The 100% viewfinder coverage gives a true-to-life perspective when composing shots.

Additional features include in-camera HDR, multiple exposure capabilities, and a comprehensive set of scene modes that assist users in achieving the best results in various conditions. The D7000 is also equipped with dual memory card slots, supporting both SD and SDHC formats for ample storage and backup options.

With its combination of high-quality imaging, advanced autofocus, robust build, and versatile features, the Nikon D7000 stands out as a powerful tool for photographers looking to elevate their craft.