Recommended ISO for DSLR cameras

There is an optimal ISO value for each DSLR, where your specific sensor provides the optimal balance between read noise and dynamic range.

ISO in the digital domain is unfortunately much misunderstood. The most important thing to understand is that picking an ISO value does not - in any way - make your digital camera's sensor more or less sensitive to light. A sensor's ability to convert incoming photons into electrons is fixed. This article by Chris van den Berge goes in more depth.

For the purpose of astrophotograph then, your camera will have an ISO value that is optimal for this type of photography. This section contains a number of suggested ISO values for popular DSLR models from popular vendors. These values are based on data from Photons to photos, sensorgen.info (now defunct), DxOMark and dslr-astrophotography.com.

Please note that these are suggestions and you may wish to do more research and/or try one above the suggested setting.