u/theCaitiff

Afternoon guys, gals, and pals, looking for some wisdom if you've got some to spare.

Planning a trip out to a dark sky area later this month and want to do a little astrophotography while I'm at it. I haven't done any before but I figure why not load up the car with gear and see what happens. I'm going with a friend who has a digital setup but I'm going to be rocking old fashioned film gear because that's what I've got.

Does anyone have any tips or suggestions for film and lens setup? I am mostly looking for milky way shots rather than telescope assisted nebula or galaxy shots. I've got a few rolls of Ilford 3200 and a couple Portra 800 on hand but I've also got time to order in something if there's a better option I am unaware of for low light conditions. I'm told I want short focal lengths and wider apertures for lenses which means I probably want my 24mm 2.5 lense or 50mm 1.4 lenses.

What brings me hat in hand to folks with more experience is a pair of quandaries.

First of all, is it worth trying to push Portra 800 to maybe get some color out of the milky way? I know Delta 3200 is actually around ISO 1000 and it's advertised at 3200 because you can push it and still get good results. How far can we push Portra 800 before it becomes a grainy mess?

Second, everything I've read for astrophotography emphasizes that f2.8 is the highest f-stop to consider because starlight is already almost non-existent, so I need a wide open fast lens. And the 500 rule limits how long an exposure I can have for a given focal length. Knowing this, I have to look at my lens choice. My f1.4 lens lets in a lot more light than my f2.5 lens, but it's twice the focal length so I'm not sure I'd be gaining anything in return.

My gut would say to grab the 3200 and my f2.5 24mm lens. The 500 rule would allow for a 20 second exposure without star trails which may not be enough with reciprocity, but if I accept my stars being a little oblong I should be able to get something. Crank the aperture wide open, focus as best I can on one bright star, and hold the release cable as long as I dare.

Is it worth considering the 50mm lens to get that f1.4 aperture or should I stick with the shorter 24mm lens and longer exposure? Can I push Portra 800 that hard or should I just embrace 3200 as my best option?