First time astrophotography with 7-14mm 2.8 - tips?

Discussion in 'Astrophotography' started by cyrax83, Dec 8, 2015.

  1. cyrax83

    cyrax83 Mu-43 Regular

    193
    Dec 8, 2014
    Hi,

    I wanted to get some tips from you fellow astrophotographers. I've never done astro before but love the pics I've seen for the milky way. I'm from Sydney so light pollution galore so no chance of it happening here.
    I'm travelling to Fiji Islands soon which is less light polluted so very keen to try out the 7-14mm 2.8 for some astroshots.

    I understand the general idea - manual mode, tripod, follow the 500 rule (7mm (~14 equiv)), 35 second shutter speed, f/2.8 and ISO 1600 and manual focus on the stars. Is this right?

    Other questions are:
    1. How do I know where the milky way is going to be in the sky? Is there an app or something I can use?
    2. How do I avoid my photo getting blown out by environment lights? For example, here are some lights in this astro shot, but the light isn't bright enough to blow out the photo. How is this possible if it was a 20-30 second exposure?
    https://c2.staticflickr.com/8/7443/9064946043_6baed9a0a1_b.jpg

    I'm hoping to capture something like this (also taken with 7-14mm @ 2.8) Photos from posts
    - His EXIF data shows 7mm, 25s, f/2.8 and 6400 ISO. Would it not be better to do 35s and perhaps drop the ISO down a little?

    Any other tips?

    Thanks
     
    Last edited: Dec 8, 2015
  2. Nathanael

    Nathanael Mu-43 Veteran

    401
    Oct 12, 2015
    It can pay to go a bit shorter than the 500 rule would dictate if you want sharp stars at 100%, since it was originally for film/lower res sensors.

    I use Sky Guide for iPhone which is pretty handy. You can check how things will be in the future. Otherwise just show up and shoot.

    In your example the foreground light is a bit blown out, I wouldn't be surprised if it's just dim light in person and a 20s exposure works out. Otherwise you can do a separate foreground exposure and mask it in photoshop.

    Manual focus on the star can be tricky, I usually look for a light/silhouette in the distance or have a friend run 50 yrds and hold a flashlight up.

    You can use Deep Sky Stacker (or similar program) to combine multiple exposure to reduce the total noise and allow you to bring out more of the detail in the milky way. That's a bigger topic you'd have to research separately but it's not terribly difficult. I would be pretty surprised if you could get something like the example you posted with M43 without stacking.
     
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  3. siftu

    siftu Mu-43 Top Veteran

    646
    Mar 26, 2015
    Bay Area, CA
    siftu
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  4. cyrax83

    cyrax83 Mu-43 Regular

    193
    Dec 8, 2014
    Fantastic!
     
  5. siftu

    siftu Mu-43 Top Veteran

    646
    Mar 26, 2015
    Bay Area, CA
    siftu
    Also the pic you linked of the Bristlecone Pine has some light painting in it for the foreground. Your cell phone or a flashlight with a tissue/cloth of over the front can help for that.

    One I did recently with headlights from a highway and a little fill from my flashlight with a tissue

    21088118520_21759b2500_b. Timeless by Siftu, on Flickr

    Also one with my cell phone inside the building and a flashlight with a tissue over it for the outside.

    20542553624_4e3cf7a2e4_b. Anyone home? by Siftu, on Flickr
     
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  6. cyrax83

    cyrax83 Mu-43 Regular

    193
    Dec 8, 2014
    Cheers thanks! I'll remember to bring a fashlight to light paint foreground a bit
     
  7. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Google has an app called Sky Map, and they have web version at Google Sky
     
  8. cyrax83

    cyrax83 Mu-43 Regular

    193
    Dec 8, 2014
    I do have Sky Guide app on my iPhone and it looks good as I can get away using it without any data
     
  9. wjiang

    wjiang Mu-43 Hall of Famer

    The constellations are pretty predictable with any of those apps. It's a rough line running through Crux, Carina, Sagittarius, Scorpius.

    For bright foreground - you might need to do separate sky and foreground exposures.