Astro photography has one major issue that supersedes everything else – It’s Dark!
Photography relies on light. When there is no light, how can you possibly get a photo? Thankfully that statement is not completely true. Modern cameras have an incredible ability to see way more in the dark than the human eye can. That’s because you can stare into the darkness for 3 or 4 minutes and still see nothing. Take a photo with a 3 or 4 minute exposure and it’s staggering just how much is able to be captured and how well it can “see”. That’s because the light capturing ability of a camera is cumulative whereas your eyes are not. The longer the shutter stays open, the more amount of light builds up on the sensor and eventually there is enough light buildup for the image to become visible when the exposure is finished. While your eyes are very sensitive to low light once you adjust to the conditions, the brain does not build up an image over a period of time and make it brighter. This is why your camera can capture amazingly bright images of the stars over a long exposure that you just can’t see by eye.
I shot this image at sunset in Norway in 2018 and all I could see was the lovely blue hour. It wasn’t until after I looked at the image on the back of my camera that I suddenly realised there was actually a small aurora happening. When I looked at the sky again there was just nothing visible but the camera was clearly able to pick up the faint aurora dancing above.
While your camera can see much more than your eye can pick up, even your camera has limits. On a really dark night with no moon, while you can easily photograph stars, the foreground can be so dark that the camera just can’t get it. So you are stuck between getting the correct exposure for the stars over a 10 second exposure (to avoid start trail movement – but that’s another topic) and a dark foreground OR expose for the foreground and get blown out overexposed stars. Welcome to the world of astro photography!
The good news is there are several solutions but all require a bit of thought, knowledge and practice. The first option is just accept a dark foreground. This can still give an excellent image with a silhouette foreground. This is best used with trees or other shapes where it is obvious what the silhouetted object is. It is by far the simplest image you can take and is a great place to start while learning the correct settings for how to capture the stars correctly.
The second method is almost the same as the first. Take your image as you did above to correctly capture the stars and milky way. However this time, while it is taking 10 seconds to capture, light paint your subject with a torch. It is a surprisingly simple technique but will take a bit of practice and a few goes to get it right. The trick is, it takes surprisingly little torch light to do it. If you have a variable brightness torch, set it minimum and paint for the full exposure time. Otherwise, use normal torch strength but for a very short time, maybe just 2 or 3 seconds out of the 10 second exposure. It is much easier with a dull torch as you have more time to finesse the lighting.
As the exposure is running, simply sweep and move the torch over the subject as needed to light it nicely. Review each image as you go and if it needs changing or adjustment then take another photo and change your sweeping motion as required to eventually get the best result. It may take 10 or 20 attempts to nail it but who cares, digital images are free. You will quickly work out where more and less light is needed. Remember different surfaces reflect light more brightly than others.
This image above is a single capture using exactly this technique. It was taken for 15 seconds at F7.1 and ISO 400 and during that time I simply moved the torch over the building. I also had a lantern placed inside the shearers shed to give the warm internal glow but the outside is 100% hand held torch. I found the roof needed a bit more than the walls because the walls were reflecting directly back into the camera whereas the roof was reflecting the light up into the sky. Ground was deliberately avoided to give a natural vignette but I did highlight the yard ramp into the shed. It took me about 20 attempts to get the torch work how I liked it but eventually you will figure out the best process and see the perfect image on the back of your camera. In the meantime, you have also captured the perfect Milky Way.
There is a 3rd method of capturing separate sky and multiple lit foreground images and combining them in layers with masking but that is way beyond the scope of this particular article.
This final astro landscape of the Cascades is also a single image. On this occasion however, instead of using a torch, I used 3 LED lights at their lowest brightness to illuminate the creek, rocks and trees. The principle is identical however and after a few attempts with lights in different positions and brightness, I got the image I was after in just one frame.
I highly recommend this technique as it is simple to achieve and ultimately requires very little post processing. You will quickly learn how much light is required in the correct position. Just start out with a very low brightness as you will be very surprised how little light is required. Remember you don’t want the torch brighter than the starlight.
I hope this sheds some light (pun intended) on a simple technique that will quickly get you some awesome images and if you have any questions or comments, just drop them below and I’ll do my best to answer.
Cheers and happy learning.