Simple Manual To get The Best Out from Your Raw Files
Shooting the Milky Way is not a simple game at first. You also need to know the right techniques, as well as handling all the equipment.
If you haven’t read it yet, I suggest you first read another article i wrote, where I explain how to photograph the Milky Way, where, when and with what equipment.
This manual is intended as a practical guide on how you can get the best files when you are in front of the Milky Way.
Photographing the Milky Way without using a star tracker
| Exposure Time | 15-20 seconds |
| ISO | 3200-6400 |
| Aperture | f/1.8 – f/2.8 |
| Focal lens | 14mm-18mm |
Without using a star tracker, you are limited to 15-20 seconds of exposure to prevent stars from starting to create star trails. 15-20 seconds is an average and depends on the focal length you shoot with and the density of your sensor.
Focal Length
If you use a 14mm or 16mm you can fix the exposure at 20-22 seconds.
If you use a longer focal length, such as a 24-30mm you need to shorten the shutter speed, for example 10-12 seconds.
Sensor density
The density of the sensor doesn’t affect much, but it still makes a difference on the length of the exposure.
With denser Full Frame sensors (46Mpx) at the same focal length, you have to shorten the exposure by 3-4 seconds.
With less dense full frame sensors (24Mpx), at the same focal length, you can add 3-4 seconds to your exposure.
Another important factor to take into consideration are the ISO.
If you have an old sensor you will have more problems with digital noise.
In order not to create too much digital noise, you have to stay below a certain ISO threshold and, without using a star tracker (to lengthen the exposure time), you will get an underexposed raw file (to be corrected in post production).
With a modern sensor you can shoot at much higher ISO without running into major digital noise issues, so you’ll get a better result, with better exposure.
Sensor Quality
The quality of the sensor certainly affects the ISO parameter.
If you have an older sensor, you’re limited to around ISO 3200.
If you have a modern sensor it will be more resistant to digital noise caused by high ISO and you can also shoot at ISO 6400-8000.
Photographing the Milky Way using a star tracker
Using a star tracker you can drastically decrease the ISO, lengthen the exposure time and work with a slightly smaller aperture, this means that you will get a higher quality file.
| Exposure Time | 60-180 seconds |
| ISO | 600-1200 |
| Aperture | f/4.0 |
| Focal lens | It doesn’t metter |
My favorite EXIFs when using the star tracker are: 120 seconds, 800-1000 ISO, f/4.0
This data depends on where you are shooting. If it’s very dark with no light pollution, you need to increase the shutter speed and/or increase the ISO.
If you’re shooting in a light polluted location or in a snowy landscape that reflects light making the sky brighter, I recommend lowering the ISO instead of decreasing the exposure time. If you have problems with stability caused by the wind, then decrease the exposure time.
Focal length depends on what you want to do, keep in mind that the longer the focal length, the more chance there is of making a mistake. Let me explain, if you shoot at 100mm you have to make a perfect pointing to the North Star and pay attention to the wind. In this case you must have a robust star tracker and if you see that the stars begin to create star trails or are slightly moved, shorten the exposure time or check the pointing of the Polar star.
With a wide angle the game will be easier.
Conclusions
If you want to get a good result from your shots of the Milky Way without the use of a star tracker, it is essential to have a bright wide angle, for example a 14-24mm f/2.8 and possibly, a sensor that can handle at least 4000-5000 ISO.
With the use of a star tracker you will get the best out of your shots of the Milky Way.
You can lengthen the exposure time and decrease the ISO, in this way you will get a file without digital noise, with more details and higher quality.
I wish you clear and starry skies!