Basic Astro Photography Knowledge


I first got interested in Astro Photography many years ago after I would go out for a sunset shoot and not get the colors I wanted.  I decided, “Well since I have a clear sky, let’s see what we get!”  Over the years I’ve learned that you don’t need a clear sky for every type of astro-shot, sometimes you only need five minutes access to the stars.

STARTERS – At the right you can see a Lightroom screenshot of a shot I did at Crater Lake National Park in December of 2012.

SETTINGS –

Camera -  Canon 5DMKIII with a 16-35 f2.8 lens

ISO 3200, f2.8 Shutter Speed 30 secs

SITUATION – It was -6 degrees out.  I had climbed up a 7 foot bank of snow to just see the lake.  This is a shot I had scouted for years.  It was the darkest dark I’d ever seen!  I had to work fast!

ADJUSTMENT – After I saw the first shot, I knew I needed more light, a higher exposure.  I also knew I couldn’t go longer exposure because I’d get streaks in the stars.  So, I bumped up the ISO to 4000 and backed off the exposure to 20 seconds.  (If I’d only known about star stacking and better noise reduction software back then!)

Image

The composition I wanted dictated the need to do a panorama, which helped me as the shots I had taken overlapped to help increase the exposure and the sharpness.

MORAL OF THE STORYEven though it was pitch dark, I relied on my basic photography knowledge to adjust my exposure, overlap my images and get the shot I came for.  Don't forget your basic knowledge.  Also, don't forget to document your experience.



What Do I Get With Different ISO's?

The image on the right is a composite created from five images shot at 20 secs @ f2.8.  From left to right the ISO's were:

2000
3200
4000
5000
6400

I think this REALLY goes to show that a higher ISO REALLY makes a better astro picture.  Now we just need to work on blending it with your camera type and the noise it creates.

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LESSONS


Lesson #1 – Sharp Stars

  • Set camera on tripod, fix focus, leave focus in manual mode, connect cable release or intervalometer
  • Set ISO to 2000, f2.8 or lowest, Shutter Speed 20 seconds – take a shot
  • Increase ISO to 3200
  • Increase ISO to 4000
  • Increase ISO to 6400
    Image

    Lesson #2 – Sharp Stars, Model Holding Light

    • Set camera on tripod, fix focus, leave focus in manual mode, connect cable release or intervalometer

    • Set ISO to 2000, f2.8 or lowest, Shutter Speed 20 seconds – take a shot
    • Increase ISO to 3200
    • Increase ISO to 4000
    • Increase ISO to 6400
    Image

    Lesson #3 – Sharp Stars, Illuminated Tent

    • Set camera on tripod, fix focus, leave focus in manual mode, connect cable release or intervalometer
    • Set ISO to 2000, f2.8 or lowest, Shutter Speed 20 seconds – take a shot
    • Increase ISO to 3200
    • Increase ISO to 4000
    • Increase ISO to 6400
    Image

    Lesson #4 – Shooting For Star Stacking – 20 x 20sec exposures

    • Set camera on tripod, fix focus, leave focus in manual mode, connect cable release or intervalometer
    • Set ISO to your best light ISO.  For me, this is 6400. Others may want between 3200 – 6400, but I’d certainly try a series at 6400.
    • Shoot 20 exposures for 20 seconds each.
    Image

    Lesson #5 – Star Trails – Long Exposure (10 minutes)

    • Set camera on tripod, fix focus, leave focus in manual mode, connect cable release or intervalometer
    • Change camera to Bulb (or manage through Intervalometer)
    • Set ISO at 4000, f 2.8, Exposure for 600 seconds
    Image