Warp Speed
Or, “How To Achieve a Star Zoom Effect In Camera”
By Brady Cabe
Let me preface by saying I am no pioneer in the realm of astrophotography and this is certainly not a concept I came up with. I saw a few really cool star zoom photos, like the ones by Aaron J. Groen and Michael Shainblum and was totally blown away. I love the almost Star Wars effect this technique provides. So let’s get to it.
“Windmill Zoom” by Brady Cabe
What Gear Do I Need?
You must have a zoom lens to achieve this effect. If you are stumbling across this blog post it is likely you already have the necessary gear for astrophotography, and there isn’t anything additional needed for this shot, unless you don’t have a zoom lens. Also, your camera settings will be identical to what you typically use for star photos.
Gear & Settings:
- Canon 6D
- Canon 16-35mm f/2.8 lens
- Really Right Stuff TVC-34L tripod and BH-55 LR ballhead
- ISO: 5000
- Aperture: f/2.8
- Shutter: 20 seconds
Now What?
Camera Setup
Setup the shot with your lens zoomed out to its widest possible focal length, in my case 16mm. It is important to note that the stars will appear to zoom out from the lens center or center of the frame, so this could lead to some pretty interesting compositions that I am anxious to try. Go wild with this.
Shutter And Zoom
Once you have the desired composition, it is time to take the photo. Press the shutter, or cable release if you are using a remote. Once the exposure is about halfway complete, in my case half of 20 seconds, slowly and steadily zoom the lens. If you have foreground subject you can use a flashlight to light paint, which was my technique here.
It’s important to note that you can also zoom from the narrow end to the wide end of the lens, which will give the opposite effect for the star trails, with the hard point at the outer end of the line. This may also change the appearance of foreground elements that will only show up once zoomed all the way to the wide setting, so remember to plan your exposure, frame, and the timing, duration of the zoom accordingly. For example, if shooting this same shot with a tight-to-wide zoom, you would want to zoom for the first 10 seconds of the 20 second exposure, and light paint at the end.
There are no hard and fast rules and you could even zoom for the entire exposure at a slower rate, etc. My particular arrangement worked well because I spent the first half of the exposure light-painting, and then started my zoom. I really wanted to avoid making a composite image later in Photoshop.
I hope you found this short tutorial helpful for this dead simple technique. Have fun out there.