Analog Gain Explained

Analog gain offers higher sensitivity and less noise than using only digital gain. The result: higher refresh rates, higher sensitivity and less noise.

 

When viewing objects through the microscope with weak lighting, (for example: when using darkfield or fluorescence applications) the image signal can be enhanced by using the "Gain" slider control in the CapturePro Software. This allows the exposure time to be reduced in order to achieve the highest refresh rates as possible for displaying live images. It is important to note however that using "Gain" will result in an increase in background noise within the image.

 

The analog gain will increase sensitivity up to 8 times. As this takes place directly in the camera, the image signal is enhanaced through the use of analog gain upstream of the ADC in the camera, and the background noise is reduced at the same time. Hence, the analog gain offers higher sensitivity and less noise than using digital gain only.

The Analog Gain increases the analog signal before it is being transformed into a digital signal (A/D-Conversion). This is why the whole digital resolution is available (8, 10, 12, or 14 Bit depending on the camera), as seen in the histogram above.
The Digital Gain increases the digital signal after it has passed the A/D-Conversion. Noise is being created during ADC. This is why the whole resolution that is theoretically possible is not achieved. Notice there are gaps in the histogram above.

 

Analog Gain is a standard feature on all the CCD ProgRes cameras.