constellation is the most dominant one in the night sky for me. Sirius, the brightest star system in the Earth’s night sky, and a couple other relatively bright stars are also easily identified. I like to call them friends of Orion. Today, I am sharing two astro photos and describe how I made them. Hopefully, my description will help you make better astro shots, or at least explain why yours might not be as appealing. You might have heard that Great Barrier Island is a so-called DarkSky Sanctuary (https://greatbarrierphotography.com/dark-sky-sanctuary-award-for-aotea/). You might also like to read my blog about how to “Shooting Stars Differently“. Let’s start with the photos.
Astrophotography – Equipment & Approach
For these photos I used the following hardware:
- sturdy tripod (doesn’t shake when there’s a breeze)
- a wide angle, zoom lens
- a digital SLR camera
- an infra-red remote shutter release
- a head torch with red light
- a watch with timer function/stop watch
When I got on site, I used only the red light of my head torch. This is to keep my eyes sensitive to the night sky. My camera has also a red-light display setting, which I used for the same reason. If red light is not an option for you, set the LCD screen brightness to the lowest. Otherwise, your eyes will have to constantly adjust for very bright vs. dark. Instead of a remote shutter, you can use the timer setting of your camera. An IR remote costs less than 10 bucks, and sometimes you want the photo taken at a press of a button and not a timer countdown.
After inspecting the night sky, I memorised the “distance” between a particular star with a fixed, terrestrial point. For instance, Orion vs. a hill in background. Once you’ve done that, you wait 15 minutes and observe how things have changed. This will give you a very good idea on how to compose. Our planet is moving and as a result, your orientation towards the stars will change.
Taking the First Shot
For the first shot, I have composed more or less for what I am interested in, I choose the widest aperture (in this case f2.8), a shutter speed of 5 s and then keep increasing the ISO until I can see what is going on. Start with ISO 10000 and increase to as much as needed or possible. In terms of focussing, I either focus during day light and tape the focus ring (put in manual focus when taping). Alternatively, as in this case, I set the focus manually to infinity, take a photo and fine tune the focus. On the LCD screen, I zoom into the centre of the photo, observe sharpness, fine tune, take a photo, observe again.
You must get the focus right first and then set your camera to manual focus, so it doesn’t auto focus. By the way, for this and most other types of photography, you do NOT want the shutter button to focus. I never use half-pressed shutter to focus. The focus is set to a back button only.
Taking the Second Shot
The idea of using a very high ISO shot is to be able to check focus and composition quickly. Once composition and focus are set, I increase the shutter speed according to the 500 rule and decrease the ISO. This rule of thumb is handy to estimate a shutter speed at which stars appear as sharp objects instead of star trails. If you are using a 50mm lens (35mm reference), you can set a shutter speed of no more than 10 seconds. I used a focal length of about 28 mm for this, which results in 17 seconds. At this stage, I have high ISO and long-exposure “correction” settings turned on. It means, that after a 17 second exposure, I need to wait about another 17 seconds where the camera shoots against complete dark to reduce noise and hot pixels etc. While shooting, I decrease the ISO to something that shows enough brightness but also results in little noise. Empirical knowledge using your camera will help. I see astro-shots at 10000 ISO, they look great on a tiny screen, but won’t when printed at A3. ISO performance will depend on camera make and model. I generally stay below 4000 ISO.
Taking the Money Shot
For the final shot, you want to increase the shutter speed to the maximum (sharp stars, no star trails) and reduce ISO to minimum. The latter will really be an experience thing. Remember, you have set LCD brightness to a minimum and you are looking at a tiny screen. Things always look great on a tiny screen. It is easier to brighten the shadows than darkening the highlights in post production. Hence, once you have made the perfect photo (of the night), take two or three more and gradually reduce ISO.
Pentax Astro Tracer Function
I use the Pentax K-1 and also have a K-50. Why do I use Pentax over Nikon or Canon? Simple, much better value. Pentax has options many other cameras do not have yet and costs less. I had a go at Nikon and Canon menus and couldn’t be bothered, Pentax has a very neat and user-friendly menu. Pentax uses in camera shake reduction vs. in lens. This has significant advantages, one of them being that the sensor in my camera is not fixed and can be moved. Via software or by the user. For instance, I can set a composition and then move the sensor in x and y direction. Very helpful for interior shots.
Further, I can use the so-called astro tracer function. For this, I need to turn the GPS unit on, calibrate the camera (moving it along 3 axes) and then the sensor will move in accordance with the movement of the Earth. This allows me to use much longer shutter speeds than the 500er rule. The sweet spot for lens sharpness will never be at the extremes. If it is a zoom lens, like 15-30 mm, shoot from 17mm to 28mm instead of going all the way. If it has aperture from f2.8 to f32, don’t shoot at the extremes unless you must.
My exposure was f5.6, 150s, iso2000, 28mm.
Blending & Other “Tricks”
A lot of seemingly great astro shots on Instagram and the like are not really good. Things always look great on a small screen. If they are also looking good on the big screen, and you compare them to yours, you might not be happy with your results. The most likely reason why the shots of the “pros” look so much better, is because they processed the photo via some techniques. Sure, experience with hard- and software, equipment, time of the year etc. will play a big role in astro photography, but often blending or focus stacking or stitching techniques were also used.
My second photo is a result of two photos blended together. One was the astro shot with the above-mentioned exposure, the foreground was shot on the day after, during golden light with a 50mm prime lens. I used a layer mask to blend them together and under-exposed the foreground shot in a manner that it would blend in well.
The term Photoshop is massive. I wouldn’t be surprised if it is used in a dictionary. Has this photo been photoshopped? I can say NO to all of my photos. Simply, because I do not use Photoshop or any related Adobe software. Adobe is industry-leading and some “professionals” believe that every photographer works with Photoshop. Great for Adobe, but very strange indeed. Imagine writing a short-story and people asking whether it has been Microsoft-Worded…
I use Lightzone and Gimp. If you are starting out, money is a factor or you just don’t like the idea of using Adobe Photoshop and CC and so forth subscriptions, there are plenty proprietary-free solutions.
Thanks for visiting my website, I hope you learned something and/or enjoyed reading this. Best wishes, Ben