That said, if you don’t have a tracker or don’t want to deal with the complexity, then you might want to try star stacking.
However, you will definitely get more detail in the sky with a star tracker, since you’re able to capture much more light in a single exposure. Blending the static foreground shot with the star tracker shot would require dealing with blending the blurred foreground of the star tracker shot with the sharp foreground of the static shot.
I do this anyways even without a tracker so that I can get detail and low noise in my foreground. This is fine if you’re just doing shots of the sky without a foreground, but if you’re capturing the foreground then it will blur in the star tracked exposures, so if you want a sharp foreground you’ll need a separate exposure (or more than one) of the foreground with the tracker turned off. You can certainly do this, but that requires lugging around the star tracker, and polar aligning the tracker every time you move your tripod. It’s hard to tell on these small images on the web, but the noise in the star stacked result is much less than the noise in the 20 second exposure.īefore we get into star stacking, you might be wondering if you could just us a star tracker, a device that sits on top of your tripod and turns with the rotation of the earth so that your camera can follow the stars, capturing long exposures with no star movement. By star stacking, we get the result on the right, pinpoint stars and low noise. Notice how the image on the left has lower noise than the 10 second shot in the middle, but the image on the left also has longer star trails. On the left is a shot taken with a shutter speed of 20 seconds, the center is 10 seconds, and the right is the star stacked result of 10 exposures at 10 seconds each.
#FREE PHOTO STACKING SOFTWARE MAC ISO#
The image above contains three 100% crops from the same night, all shot with the Nikon D810A and the Nikon 14-24mm f/2.8 lens 14mm, f/2.8, and ISO 12,800. Right: Star stacked result of 10 exposures at 10 seconds each – Pinpoint stars and low noiseĪll shots with the Nikon D810A and Nikon 14-24mm f/2.8 lens 14mm and f/2.8 Left: 20 seconds ISO 12,800 – Note the star trailsĬenter: 10 seconds ISO 12,800 – Pinpoint stars but more noise (brightened to show detail) Or you can combine a star tracker with star stacking for incredibly low noise.
You can either use a star tracker with very long shutter speeds to capture a lot of light and thus a high signal to noise ratio, or you can use star stacking, a method of capturing multiple photos with shorter shutter speeds that are then aligned and averaged in software to reduce noise. Noise reduction tools these days are great, but they can’t fix everything all the time.įortunately there are ways to capture both pinpoint stars and achieve low noise. If you try shooting with a short enough shutter speed to capture completely motionless stars, the noise level can be so high (depending on your camera and lens f-stop) that the exposure is either unusable or needs a ridiculous amount of noise reduction, resulting in large size prints that can look very grainy or blocky due noise or noise reduction. The result is that you’re usually shooting with a shutter speed that captures enough light for tolerable noise, but it’s also probably long enough that the stars trail in the frame. So you’re stuck using a shutter speed that isn’t long enough to capture enough light for a high signal, and having to use a high ISO as well to boost the signal to a usable level, which can add additional noise to the image (although how much depends on your camera). However, when shooting the Milky Way you’re usually going for short star trails, or completely pinpoint (trail-less) stars, which means you’re limited in how long you can expose before the stars appear to move too much in the frame. A higher signal will result in less noise even with a high ISO (depending on your camera, modern sensors are much better). If you exposure for a longer period of time, you’ll capture more light, and have a higher signal to noise ratio, meaning less noise.
But the noise isn’t all just from the high ISO. If you’ve done any night photography, then you’re likely very familiar with the noise of exposures in low light using a high ISO. The green color in the sky is from airglow. The Milky Way rises over a fairly intimate canyon view in Canyonlands National Park in Utah.