I just started studying astrophotography and your videos make the most sense. You have an amazing ability of simplifying a topic and conveying all the important details. Thank you!
Unity gain is almost always the best choice, I think, at least for DSOs. That's the second request I've had for an offset video in a couple days. Sounds like a topic we should cover. Techniques to address vary a bit according to shooting strategy.
Thanks, yet another great video! It does, however, make me wonder why you would perform the gain translation in the camera and not in post-processing? If you recorded absolute values, then you could decide on the gain when post-processing. If you get it wrong and blow out some details, then you just lower it. If that is done in the camera, then you lose that data forever. I know this was a simplification and you have all kinds of funny things going on, like unity gain, so it may be a purpose I don't fully appreciate that makes the gain conversion desirable in the camera.
Your post makes perfect sense. Unity gain performs the useful function of getting the signal well over the read noise with very little penalty in dynamic range.
So do i have this right? Set exposure duration as limited by tracking accuracy (to limit motion blur) and duration to be less than saturation for scene (signal and camera thermal electrons) at chosen gain level. Benefit to analog gain being to limit influence of read noise and a/d quantization uncertainty present in shorter durations. #subscribed
Opinions differ on the best shooting strategy. Over the years, I have leaned more and more toward shorter exposures. It mitigates tracking errors and issues due to night breezes and seeing (and even wildlife, such as the owl that recently decided to land on the telescope). But since I live in the back woods and there is no light pollution, I don't have to deal with issues like shot noise. Short exposures won't work for everyone. Exposure length is generally light curve to the left of the histogram but offset enough to put a little space from the bottom left of the light curve and the left of the histogram, though offsets vary by camera (this is different from ordinary photography where you expose to the right). Unity gain is usually the sweet spot that gets you out of most of the electronic noise while giving a great balance of dynamic range, though it will cost some in well depth.
Interesting topic, but very confusing explanation. Instead of addressing gain as a hardware feature and explaining inherent limitations of high gain in terms of electrons and currents/volts, gain is represented as what appears to be a scaling/rescaling during an image processing step.
Unfortunately, this is an exceedingly complex topic and this video only covers it in the most rudimentary way. There are fundamentally two sides to the modern gain process: analog amplification on the one side, and digital gain on the other. This video focuses on the latter, as its where we really impact an image with processing. But throughout the entire process, the camera sensor always operates at maximum sensitivity, and newer sensor/camera designs make gain semi-irrelevant by digitizing the data so that gain can be handled and changed entirely in post while other cameras have two or more gain converters to better handle wider ranges of light while shooting. Pushing into this deeper would require going into each topic separately, and since how gain is managed is something of a designer secret one can only work with certain generalizations. In short, it is a deep, deep warren of rabbit holes.
@@SKYST0RY Agree. I hope that one day you can make a longer video with more detailed explanations for those of us who would like to learn more. You have the knowledge and it would be great to hear from you again. Thanks a lot.
Wait. I’m a newbie. I thought you were arguing for gain zero. I have a ZWO ASI2600MC pro. The description of this camera says that at gain 100, the read noise plummets and the dynamic range improves. And ZWO recommends a gain of 100 for nearly all applications. Is this gain 100 what you are calling unity gain?
@@OilPainter01 The video isn't really an argument for any gain setting. That will depend on what you are shooting and what you are trying to accomplish. I don't know the specs for the ZWO ASI2600MC but it sounds like you are describing unity gain. Unity is usually your best choice for most DSOs, unless you have some kind of unusual setup or shooting circumstance.
I just started studying astrophotography and your videos make the most sense. You have an amazing ability of simplifying a topic and conveying all the important details. Thank you!
Unity gain for life! I’m waiting for you to teach me about offset and pedestal and the best way to set that :)
Unity gain is almost always the best choice, I think, at least for DSOs. That's the second request I've had for an offset video in a couple days. Sounds like a topic we should cover. Techniques to address vary a bit according to shooting strategy.
Thanks, yet another great video! It does, however, make me wonder why you would perform the gain translation in the camera and not in post-processing? If you recorded absolute values, then you could decide on the gain when post-processing. If you get it wrong and blow out some details, then you just lower it. If that is done in the camera, then you lose that data forever.
I know this was a simplification and you have all kinds of funny things going on, like unity gain, so it may be a purpose I don't fully appreciate that makes the gain conversion desirable in the camera.
Your post makes perfect sense. Unity gain performs the useful function of getting the signal well over the read noise with very little penalty in dynamic range.
que detalle, gracias por este video!!
Gracias!
I set my SvBony 705c (asi585) to 250 and my SvBony 405cc (asi294) to 120.
For almost all DSOs, I just generally set the camera for unity gain. It is frequently the best compromise.
Absolutely! That's why I always go to 130 on the Ares camera, 5 points over official unity.
hey! yo tambien tengo esas camaras, recien las compre. gracias por la referencia!!!
So do i have this right? Set exposure duration as limited by tracking accuracy (to limit motion blur) and duration to be less than saturation for scene (signal and camera thermal electrons) at chosen gain level. Benefit to analog gain being to limit influence of read noise and a/d quantization uncertainty present in shorter durations. #subscribed
Opinions differ on the best shooting strategy. Over the years, I have leaned more and more toward shorter exposures. It mitigates tracking errors and issues due to night breezes and seeing (and even wildlife, such as the owl that recently decided to land on the telescope). But since I live in the back woods and there is no light pollution, I don't have to deal with issues like shot noise. Short exposures won't work for everyone. Exposure length is generally light curve to the left of the histogram but offset enough to put a little space from the bottom left of the light curve and the left of the histogram, though offsets vary by camera (this is different from ordinary photography where you expose to the right). Unity gain is usually the sweet spot that gets you out of most of the electronic noise while giving a great balance of dynamic range, though it will cost some in well depth.
Interesting topic, but very confusing explanation. Instead of addressing gain as a hardware feature and explaining inherent limitations of high gain in terms of electrons and currents/volts, gain is represented as what appears to be a scaling/rescaling during an image processing step.
Unfortunately, this is an exceedingly complex topic and this video only covers it in the most rudimentary way. There are fundamentally two sides to the modern gain process: analog amplification on the one side, and digital gain on the other. This video focuses on the latter, as its where we really impact an image with processing. But throughout the entire process, the camera sensor always operates at maximum sensitivity, and newer sensor/camera designs make gain semi-irrelevant by digitizing the data so that gain can be handled and changed entirely in post while other cameras have two or more gain converters to better handle wider ranges of light while shooting. Pushing into this deeper would require going into each topic separately, and since how gain is managed is something of a designer secret one can only work with certain generalizations. In short, it is a deep, deep warren of rabbit holes.
@@SKYST0RY Agree. I hope that one day you can make a longer video with more detailed explanations for those of us who would like to learn more. You have the knowledge and it would be great to hear from you again. Thanks a lot.
Mine is set to 101 and will not be changing.
Until i watch all of your video, probably ;(
Gain is different model to model. I find unity gain is best for most DSOs.
@@SKYST0RY yeah 100 is unity but like cuiv, no harm in me using 101 to make sure :)
@@jesuschrist2284 Me, too. I push about 5 points higher to account for possible variance, but same idea.
Wait. I’m a newbie. I thought you were arguing for gain zero. I have a ZWO ASI2600MC pro. The description of this camera says that at gain 100, the read noise plummets and the dynamic range improves. And ZWO recommends a gain of 100 for nearly all applications. Is this gain 100 what you are calling unity gain?
@@OilPainter01 The video isn't really an argument for any gain setting. That will depend on what you are shooting and what you are trying to accomplish. I don't know the specs for the ZWO ASI2600MC but it sounds like you are describing unity gain. Unity is usually your best choice for most DSOs, unless you have some kind of unusual setup or shooting circumstance.