ISO and gain tutorial

[Astrofriend]

A lot of people have asked me about the iso setting and what is going on inside the DSLR camera.

I have tried to do a simple tutorial about this on my homepage:

http://astrofriend.eu/astronomy/tutorials/tutorial-iso-dslr/tutorial-iso-dslr.html

 

Now when DSLR cameras get better and better it's not that big advantages to use high iso setting. On earlier high noise readout cameras you could raise the signal above the readoutnoise by using a high iso setting (but depends on the camera if the amplifier was good enough), but in the same time you lower the dynamic range. With a better new camera you can lower the iso setting and stretch the data in your imageprocessing software and still have the same (or almost) low signal details. And with that get a higher dynamic range (don't saturate or clip the high levels).

 

With my new Canon 6D I normally use iso800 but also iso 400. Modern Nikon cameras with Sony sensors are even better. Normally you can read about isoless cameras, that's the ones that can take advantage of lover iso setting. Depends on the object what to prefer.

 

One important thing to know, the iso setting doesn't change how many photos the camera detect, just how the camera read out the sensor.

 

Hope I clearify and not confuse with my tutorial.

 

/Lars