Gain, Offset, Read Noise, Exposure time?! Let's clarify

Important disclaimer: what I'm presenting here is my understanding of the matter - it may be extremely simplified and not completely accurate. Please let me know in the comments about any errors I made!

So, I've had tons of requests about optimal exposure time - but first, I want to clarify a bit about gain, offset, dynamic range, read noise, and how they're all linked together - and at the same time, how to choose the "right" values for them (there's no right values, but I'm lazy, so I just choose something that seems like it makes sense!). Hopefully this is helpful!

#astrophotography

[SKYSTRY]

On a more serious note, your videos are masterful. I've worked professionally in photography and videography for many years, and every time I watch your videos I learn something. Lots of things. Very good info and very well presented.

[johnposavatz]

Two years later, and this content is still golden! Thanks for teaching me these concepts - super useful for a new astrophotographer.

[davidrousseau]

As Einstein used to say: "If you cannot explain it simply, you do not understand it well enough yourself". Your explanation is LIMPID :) On behalf of all the noobs : Thank you so much!!!

[rudycajuso]

Best explanation I have ever seen. Just makes more sense now. Can't wait for your next video.

[PeterClarke]

Thank you for a logical explanation which I found to be refreshing instead of the usual " I used this value and look at my No depth and only the message" Don't question just follow what I am doing". Thank you Kurt.

[DrReinerHutwelker]

Again a great video, Cuiv. As a beginner I have treated the topics this way so far: As long as there is a wall I don't need a door. Thanks for the many doors in your videos.

[prnzssLuna]

That's probably by far the best video on that topic I've ever seen, thanks for that.

[KingLoopie]

Just enough explanation to really help me along! Thanks, Cuiv! 👍

[calumcadwallader]

I can’t tell you how much I appreciate this and all of your NiNa videos, thank you so much 🙏

[tedmcgee]

I've watched a lot of videos, some are so complex you have to have a doctorate to understand, some are so simple that when you are finished you know less than when you started. As the three bears would say, this is just right. Thanks so much.

[davidaylsworth]

This clears up a lot of question I have about dedicated astro cameras.

[Codyyyyyyyyyy]

Awesome video Cuiv! This is the best explanation of gain and read noise I've come across on youtube.

[johnmacdougall]

"...all about swamping the read noise...". Too funny. Thanks for the informative and fun videos

[vasodyss]

Thanks Cuiv, I just bought a 294MM Pro and couldn't get my head around all these values by looking at forum posts. You explained everything perfectly!

[jamesmunoz]

This is probably the best video explaining this I’ve ever seen.
👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻
I proudly wear your T-shirt

[beorn]

Thanks for explaining it so well and the "don´t worry too much about it" attitude! That´s very much apprechiated by a beginner, worrying too much about basically everything <3 :D

[weegieb]

Thank you for explaining this. i was looking at these charts for sometime, not being exactly sure of how to interpret them. Now i can say i understand.

[johnjames]

Great explanation. I have watched Robins videos several times (they are very good) in the past, but just wasn't crystal clear for me about all this offset, gain stuff since I used to use a modified Canon DSLR. Now I get it!! Logical step by step and the explanation how it all works always works for me.

[JeffHorne]

Chic, you are on fire lately, and I absolutely love your videos. For the past 9 months, I’ve watched and read everything I could find about imaging with dedicated astronomy cameras, and in particular, gain/offset and how it all relates to DR and noise. I’ve never understood what I should really be doing with offset until watching this video. Your explanations of everything in this video, actually, resonate with me more than any other explanations I’ve found. So, thank you again! Also, sounds like NINA might benefit from renaming it from “optimal exposure time” to “optimal minimum exposure time”, if it’s truly calculating how much time you need in order to swamp the read noise. Maybe?

[WiseEyez]

' extremely simplified ' he says : ' ) My head is spinning from all this information, well explained Cuiv, gonna have to come back to this video a couple more times!