Deminishing returns.....

Started 3 months ago | Discussions thread
Astrozoid Contributing Member • Posts: 846
Re: Deminishing returns.....

Alen K wrote:

Astrozoid wrote:

When you use LENR you get a double whammy hit because not only have you lost half the signal you could have recorded, you are adding noise in each dark that you shoot in the camera. You would add a lot less noise with a good master dark.

I don't understand this. Please elaborate. If I take N light frames with LENR on (generally a bad idea, I agree), I will be using N dark frames, one for each light. Mathematically, there should be no difference between averaging N frames, each with a dark pre-subtracted, and averaging N frames then subtracting the average of N dark frames (the master dark).

Yea, except for one thing.

I can construct a master dark out of as many subs as I like when I shoot darks in my garage.

I don't have to limit it to the same number as the number of lights.

If you shoot 16 lights with 16 darks, you will inject X amount of dark-frame subtraction calibration noise. With 64 darks, I will only inject 1/2 as much.

So, separate darks vs LENR darks will inject less noise to the final stack.


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