Question on bit depthPosted By Ron Wodaski |
1. No. Bit depth is the number of brightness levels in the image. An 8-bit image has 256 brightness levels. Adding two of them together, you still only have 256 brightness levels, not the 65,535 levels of a 16-bit image.
2. Dynamic range is the number of steps from the smallest possible value to the highest possible values. The size of the step is equal, roughly, to the noise of the system. An 8-bit camera can have no more than 256 steps in its dynamic range; a 16-bit camera can have no more than 65,535 steps. To determine the dynamic range of a camera, divide the full well capacity by the read noise. If these numbers are not available, you can't calculate the dynamic range.
To get a camera with good dynamic range, you need a 16-bit camera with a large well depth and low noise. The ST-7E is probably the entry level of cameras with a large dynamic range. The payoff for a bigger dynamic range is better S/N in your images, and more detail for a given exposure time.
Ron Wodaski
author of "The New CCD Astronomy"
http://www.newastro.com
2. Dynamic range is the number of steps from the smallest possible value to the highest possible values. The size of the step is equal, roughly, to the noise of the system. An 8-bit camera can have no more than 256 steps in its dynamic range; a 16-bit camera can have no more than 65,535 steps. To determine the dynamic range of a camera, divide the full well capacity by the read noise. If these numbers are not available, you can't calculate the dynamic range.
To get a camera with good dynamic range, you need a 16-bit camera with a large well depth and low noise. The ST-7E is probably the entry level of cameras with a large dynamic range. The payoff for a bigger dynamic range is better S/N in your images, and more detail for a given exposure time.
Ron Wodaski
author of "The New CCD Astronomy"
http://www.newastro.com
