ZWO ASI1600mm - Offset

[woodblock]

The driver for this camera allows me to set a gain and offset. What is the purpose of the offset and how is it used? What would be a good value?

Cheers

Steve

 

[paul]

 It is a slightly positive value treated as black There is no good reason to mess with defaults that I am aware of. 

[ApophisAstros]

I always thought that Gain was like ISO on DSLRS , but its only on CMOS not CCD as i am aware so probably best to leave alone as Paul said.

OFFSET  No Idea.!

Roger

[TerryMcK]

This website article explains the question you have asked

https://www.edmundoptics.com/knowledge-center/application-notes/imaging/basics-of-digital-camera-settings-for-improved-imaging-results/

 

Just for reference with a dedicated astro camera I leave the offset at the default value, as stated in the driver, which in the case of all my current ZWO cameras happens to be 8. I used to have an ASI1600 but cannot remember what the default is with that one.

[woodblock]

Thanks, I've left it at default but I just wondered what it was for.

[paul]

Basically it's a bad idea to use 0 adu as your zero point because all measurements are subject to noise and uncertainty, signals close to zero could be clipped to zero. That randomly loses information for faint detail. The camera applies a fixed value (the offset) to all values read to minimise this. 

I'll worry about offset when my LP is zero😉.