thanks for the explanation. It's not like shooting highway traffic at night is it? Light trails because those people get iso 100, 200. All good
No, the lights from cars on the highway are much brighter than the stars. If you try to shoot the Milky Way at base ISO, you better have a very fast lens. I have only had experience shooting MW shots with a f2.8 lens, I still have to shoot at at least ISO 800. That was my reasoning for picking 1600, one stop of light slower lens needs one stop of light more ISO. With a star tracker, I would be able to take longer exposures, thereby reducing my ISO. Something I plan on doing next time. Another thing that can be done is to stack the images. I dont remember the formula, but it goes something like you increase your light by a third of a stop every time you double your stack. So, 1+1=2, 2+2=4, 4+4=8. 8 f4 shots stacked would appear like the same shot at f2.8, but to get to the next stop, you need to do 8+8=16, 16+16=32, 32+32=64. 64 of the same exact shot. When each of the shots are between 30 seconds and a minute, it becomes unrealistic real quick and the location of the MW strays too much for stacking to even be made possible, depending on the composition.
