Shooting the stars

November 27, 2017 by Mike in Uncategorized 0 comments
Shooting the stars

Shooting the stars, or astrophotography, is one of those specialist sides to photography. You don’t need to have fancy kit, but it does help.

As there is very little light about, the camera needs to be good at low light capture and your lens needs to be as fast as possible….and if you’re photographing the milky way, or trying to capture shooting stars, you’ll need as wide a lens as possible.

I shot my first astro shots with the canon 350d and the 10-20mm sigma, they didn’t come out that well, but I was hooked and wanted to get my image quality better and wanted to get some milky way shots.

Now I shoot with the A7rii (I haven’t upgraded the firmware and I am not going to as apparently the update automatically reduces what it thinks is noise…..and it seems to think stars are noise….) This is know as the “star eater” upgrade…..The A7rii is great in low light and gets great shots of the stars.

Lenses

I use two different lenses, the samyang 14mm f2.8 and the Zeiss Batis 25mm f2. So With the samyang,it is a really wide lens, and surprisingly sharp for the price I paid for it. The batis is a little tighter but is a phenomenal lens. I switch between the two, sometimes the batis is my favourite and other times the samyang is my favourite.

 

If you’re shooting on a crop sensor, I’d recommend something around 10mm, like the 10-20mm sigma. This will give you you a nice wide angle to get as much of the sky in as you want, with the flexibility to zoom in to 20mm. It is definitely a nice compliment to the kit lens to give you those funky wide shots that the kit lens doesn’t quite get to.

The Steps

Part 1

  1. You need a sturdy tripod
  2. Turn the mode dial to manual
  3. Turn on the self timer (to 2 seconds if you have that option).
  4. Turn off any image stabilisation
  5. Switch your white balance to Tungsten (Might be called indoor or incandescent)
  6. If you are using a zoom, zoom out as wide as possible
  7. Switch on live mode
  8. Switch to manual focus.

If you have a lens with no focus markings on, this is the tricky bit:

Find a bright star that you can see in live mode and hit the magnify button to help focus. Now turn your focus ring until you can see the star clearly and in focus. Then keep the focus in manual and try not to touch it. With this method, you might have to take a few photographs to dial in the focus so it is tack sharp. Come out of live mode and continue from point 10.

Part 2

  1. If you do have focus markers on your lens, set your focus to infinity.
  2. Set your iso to about 10,000
  3. Set your aperture as wide as possible.
  4. Set your shutter speed to about 6 seconds and take a shot.
  5. Depending on the moonlight and any ambient light from any cities near by, your shot might be over exposed. If so, bring your shutterspeed down and retake the photograph until you get a good exposure………..This first step is mereley to dial in the exposure and find a pleasing composition.
  6. Once you’ve got good composition and exposure , start bringing your iso down and your shutter speed up.

Just don’t take your shutter speed up too much though….otherwise the stars will start to streak from the rotation of the earth. Unless that’s the look you are going for….then get them streaking as far as possible!

Click here for the downloadable PDF file of all the above steps.

The maths to get clean stars

If you are shooting an APS-C sensor, divide 400 by the focal length, that will give you your maximum shutter speed. So for your 18mm you want a max shutter speed of about 22 seconds.

APSC 400 rule

400/focal length = maximum shutter duration in seconds

Wide open kit lens (usually 18mm) so:

400/18 = 22       So if you have a kit lens on an APS-C sensor, wide open, you can keep the shutter open for 22 seconds.

Full Frame 600 rule

If you are using a full frame camera, divide 600 by the focal length.

600/focal length = maximum shutter duration in seconds

Wide open kit lens (usually 24mm):

600/24 = 25.     So if you have a full frame with a kit lens, wide open at 24mm, you can keep the shutter open for 25 seconds.

So when I shoot with the 14mm, my maximum shutter speed would be 42 seconds. So you can see why a full frame sensor and a wide angle lens would be beneficial to astrophotography.

Then it’s just a case of coming up with interesting compositions and and following the patterns of the moon and the stars to see what might give an interesting sky. I only really dabble in this field taking wide shots with the milky way or the moon or a starlit sky. If you do some research on line you’ll find so many amazing photographs especially the closeup shots of nebulas, gas clouds and planets. But this needs tracking equipment, telescopes and things like that!!

If you really want to get into astrophotography, I’d start by getting a wide manual focus lens around 10mm for a crop sensor or about 14mm for a full frame sensor. The manual focus lens will enable you to easily get focus without having to go into the live mode, if you get a prime lens it will be faster (wider aperture) and without all the electronics, it’s usually a bit cheaper.

So that’s about it.

Let me know how you get on with your astrophotography by sending me an email, leaving a comment below or logging on to my youtube page and leaving a comment. And if you like the video above, please subscribe to my youtube page for weekly tutorials on photography.

Also if you’d like to learn something that I haven’t covered, please get in contact and I’ll see if I can help.

Thanks

 

Mike Smith

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