Light has to get to the sensor to not block up your blacks, causing noise, when photographing Milky Way skies. The problem is when you kick up the ISO that creates noise as well right? I’ll share a technique that gives you light but can process out the noise. Know that it’s a dance and you’ll have to learn the steps that work for your camera and lens.
What’s going on?
It’s night. It’s dark. But you want to see a foreground against a black silhouette. While silhouettes can work, they can get boring after a bit if that is the only foreground element you feature. You need to get light to your sensor or open up those shadows in post production. The problem with opening dark shadows is you have a very small number of pixels in those shadow areas. When you make them brighter you highlight the lack of quality in those pixels and it’s pretty hard to fix. You already have the widest aperture selected and still not enough light. So the answer is to increase the ISO. But wait Bob, that’s going to be noisy as well, correct? True, but we have a solution. Check the next section for the answer.
High ISO capture and processing
In this example I have the ISO cranked up to 20,000. There’s some serious noise. If I was to make a single image and try to reduce the noise, I could do that somewhat, but it would be less than ideal as I would also lose detail. Here’s the ticket.
When capturing your images, make multiple copies. Twenty photos were taken with one second in between each frame using the Interval Shooting Mode on my OM System micro 4/3rds OM 1 camera (as of the posting of this link, there’s a $500 discount to $1,699). Other manufacturers have different names for this feature Nikon’s Interval Timer, Canon’s Timer Shooting and Sony’s Interval Shooting Func. among others. If you have an older model camera you can add an external intervalometer to achieve the same thing. The idea is to capture these images while having as little contact with the camera as possible.
Immediately following the twenty light exposures, the lens was covered with and 10 dark frames were made using the exact same settings. Basically, you are making images of the noise patterns of your sensor. These dark frames will be helpful for the software or processing to recognize and remove noise.
Noise reduction software
If you are a MAC user the is an application called Starry Landscape Stacker. You’ll find it in the Apple App Store. It sells for about $60. If you do much Milky Way processing you will find it highly worthwhile. PC users have a similar program that is free, called Sequator. Both of the programs take the multiple images made, align them and process out the noise. A bonus is if a plane or satellite passed through the frame during you capture it will be removed along with the noise which is a sweet bonus as there are lots if things streaking through the skies these days. Here are links to another article using Starry Landscape Stacker. And another article on handling noise from fellow Photofocus author Ken Lee.
Finishing the noise free image
In the next article I’ll show my finishing touches including moving mountains! When you tilt your wide angle lens camera up you create distortion. That can be cool but many times I prefer an image that is not distorted. You can decide whether you like the original or the “fixed” image.
Yours in Creative Photography,
Bob
