The Expose tab is used to control camera exposures, in conjunction with the Settings tab. The functions of this dialog are only active if a camera has been activated using the Setup tab.
The Expose button starts an exposure. During an exposure, the Expose button is disabled, and the Stop button is enabled. The Stop button allows you to terminate the current exposure or exposure sequence. Note that some camera drivers lock up the computer during camera readout to prevent other programs from interfering with the readout process. Therefore it may not be possible to abort an exposure during readout.
The exposure duration is determined by Minutes plus Seconds. You can enter an exposure from 0.001 seconds up to the maximum allowed by the particular camera. If the exposure is set lower than the particular camera allows, the minimum permitted exposure will be used.
If you have configured the driver for video capture (see Video DirectShow), an AVI movie is recorded during the selected exposure time. The destination file path is set using the Settings tab.
The Delay field allows you to specify a delay time after the Expose button is pressed before the exposure will begin. When a sequence of images is taken, this delay is added before each exposure in the sequence. When the autoguider is running, a minimum delay of five seconds is automatically added to allow time for the autoguider to settle before each exposure; if necessary you can increase this time by setting Delay to a value greater than 5.
The type of exposure can be set using the Type radio buttons (Note: this function is disabled if Simple Auto Dark is enabled on the Settings tab). Normal exposures are usually taken using the Light setting; the exposures may be automatically calibrated as determined by the Settings tab. The remaining exposure types are used for taking calibration frames; as such, these images are not automatically calibrated. The Bias frame is a minimum-duration dark frame (shutter closed). The Dark frame is a normal exposure with the shutter closed. The Flat exposure setting is used for taking flat-field frames; it differs from the Normal setting in that automatic calibration will not occur. If the camera does not have a shutter, you will be prompted to cover the aperture when taking a dark frame.
The New Buffer control forces MaxDSLR to create a new image buffer for each exposure. When this control is off, the previous image buffer will be reused if it is still available.
The Sensitivity drop-list is used to select the sensitivity (ISO speed) to be used. If the camera does not provide a choice of sensitivity but does support automatic color conversion, it is used to select between Monochrome (raw unprocessed) and Auto Color (converted) images. Otherwise this control is greyed out.
Changing the settings during an exposure or exposure sequence is allowed, but has no effect on the current imaging activity. The new settings only take effect when the Expose button is clicked.
Two status fields are provided. The left-hand status field shows the status of the main camera. The right-hand status field shows the status of the autoguider, if present. Status information includes the camera state and exposure time. There is also a progress bar that shows graphically the progress of the exposure.
Mirror Lock is a push-on, push-off button that turns on or off the mirror lock mode. This mode adds a delay after the mirror flips up and before the shutter opens, to allow vibrations from the mirror motion to dampen out. If the selected camera does not have an internal mirror, or does not support locking up the mirror, this button does not appear.
Note: Subframe settings can only be changed when the Settings tab is displayed. Dragging the mouse on the image when the Expose tab is visible will have no effect.