The CAM submenu of the DN100 digital camera system can be accessed by right-clicking the mouse button while the cursor is hovering on the lower portion of the image display window and no other menus are currently activated. This important menu contains a number of features useful for measuring and calibrating image focus, controlling exposure mode and time, and adjusting camera sensitivity. Each of these settings should be carefully scrutinized before capturing images displayed in the software live window.

Many of the buttons in the CAM menu are both right- and left-click sensitive, providing a high degree of software control through the mouse as opposed to conventional keyboard tactics. Left-clicking a button will typically decrease, and right-clicking a button will typically increase, the button's function value.

The Focus Rating is a relative value of image focus (sharpness) represented by the number of ticks that are illuminated in the Focus Display indicator of the CAM submenu (illustrated in Figure 1). A numerical value for the focus rating is also displayed to the far right of the display indicator and labeled FC ### (where ### represents an integer value). Higher focus ratings indicate a better microscope focus for the specimen that is being viewed. In order to adjust and maximize the focus rating, the microscopist must raise or lower the microscope stage (or the nosepiece in some earlier models) using the coarse and fine focus knobs.

The Exposure Mode button (Figure 1) can be utilized to toggle between exposure modes on the camera control unit (CCU). Each of the four available exposure modes is described in the Exposure and Camera Sensitivity section. The settings of each of the four exposure modes from the CAM menu are summarized below:

• PROG (program AE mode) - In the program auto exposure mode, the +-xEV button (Compensation; see Figure 2) can be used to adjust the exposure compensation over a range from -2.0 EV to +2.0 EV in 0.3 EV steps.

• S_AE (shutter speed priority AE mode) - The Exposure Time button (Figure 3) can be used in the shutter speed priority mode to set the shutter speed over a range of 1/1000 second to 4 seconds. The Compensation button can also be used to change the exposure compensation over a range from -2.0 EV to +2.0 EV in 0.3 EV steps.

• MANU (manual exposure mode) - In the manual exposure mode, the Exposure Time button (see Figure 4) can be used to set the shutter speed over a range from 1/1000 second to 60 seconds. The Analog Gain button (also illustrated in Figure 4) may then be used to set the camera gain between a range of x1 (AG value of 100) to x46 (AG value of 4600).

• F_AE (focus priority exposure mode): The Compensation button (Figure 5) can be used in focus priority mode to change the exposure compensation over a range from -2.0 EV to +2.0 EV in 0.3 EV steps.

When using any exposure mode other than manual, the DN100 camera control unit will automatically adjust the CCD exposure settings to maintain proper exposure of the image projected into the camera by the microscope optics. However, if the AE_L button (the Auto Exposure Lock, illustrated in Figures 1, 2, 3, and 5) is enabled, the DN100 camera control unit locks the current exposure settings and does not attempt to make any adjustments to the selected settings. The text on the AE_L button surface will turn red when the AE lock is enabled to warn the operator of the fixed exposure condition.

The CAM menu also contains a number of controls that are useful for performing digital image correction functions. Routine operation of the image correction controls located in the CAM submenu is outlined briefly as follows:

• Gain Adjustment - This button controls the gain (brightness) of the displayed image and will be applied to captured images. The mechanism by which the gain control affects digital image appearance is discussed in the Image Correction Features section.
• White Balance Setting - Clicking the WB_* button will launch the white balance adjustment for the image. WB_N indicates that the white balance has been set, while WB_D indicates that the white balance has been restored to its factory default. White balance effects on digital image appearance are discussed in the White Balance Calibration section.
• Tone Setting - The TON_# (where # represents the tone setting number) button will toggle through the five available tone (gamma) settings: Low, Mid, High, Linear, and Enhance. A description of the individual tone controls and how they affect the appearance of the displayed image is discussed in the Image Correction Features section.
• Effect Setting - Clicking the Color button, illustrated in Figure 1, will toggle through the five available color effect settings: Color, Nega, Blue Back, B & W (black and white), and Sepia. The color effect settings are discussed more thoroughly in the Image Correction Features section.
• Color Adjustment - A series of three buttons, R###, G###, and B### (where ### represents the 8-bit RGB color value), can be used to adjust the red, green, and blue color balance of the displayed image. The effects of color balance modification on the appearance of the displayed image is discussed in the Image Correction Features section.
• Sharpness Adjustment - Left or right clicking on the SP_# button (where # represents the sharpness setting number) will toggle through the six available image sharpness settings, which is discussed in greater detail in the Image Correction Features section.
• Clear Button - The CLs button will restore the settings of the CAM menu to the values previously stored in the active configuration.

In conclusion, the DN100 camera system software CAM menu offers a wide spectrum of features that enable the user to monitor the effects of the camera sensitivity, camera focus, and exposure characteristics on the resulting digital image. In addition, the CAM menu is equipped with an array of controls that allow the user to perform real-time image enhancement operations. These features are extremely useful in producing sharp, crisp, and accurate digital photomicrographs that display an excellent blend of color balance, saturation, and contrast.