Stacking question

I had a question regarding bias and flat frames. Assuming I use the same camera, ISO, lens and focal length, can I use the same bias and flat frames? Wouldn't the flat frames always be the same for a particular lens? How would it be different from correcting vignetting with lens correction in lightroom or peripheral illumination correction in DPP?

After reading the DSS FAQ, I understand light, dark and flat frames, but I do not understand how bias frames work.

Flat frames not only correct vignetting, but also any dust motes in your imaging train.

LR lens correction profiles vary wildly in quality. Some are acceptable, some borderline unusable.

Compare these, first two images with two different LR profiles and then a flat field corrected image:

jannefoo wrote in post #14633235
LR lens correction profiles vary wildly in quality. Some are acceptable, some borderline unusable.

Compare these, first two images with two different LR profiles and then a flat field corrected image:

[IMG]
(Unusable)

[IMG]
(Acceptable)

[IMG]
(Perfect correction with flat field)

Nice.

To reword my previous question, if you are using the same lens, with the same settings, could you use the same flat frames? Or is it better to take new flat, dark or bias frames every time?