All images by Alan Dyer
In Part 1 and Part 2, I reviewed factors to consider when buying a new camera. However, before you make the plunge, I suggest putting the camera you already own to work. Use the DSLR camera you have now for tripod-mounted nightscapes, constellation portraits using a simple star tracker, and close-ups of targets with your telescope.
Push your camera to its limits by shooting everything you can in the sky. You’ll learn the basics of setting exposures, framing, focusing and finding your way around its menus.
However, when it comes to images of nightscapes (especially the Milky Way over a scenic landscape, or a display of Northern Lights), the most critical piece of gear is often not the camera. The first purchase to consider, other than a sturdy tripod, may be a new lens.
Fast and Wide
The 18-55mm “kit zoom” that might have come with your camera is fine for bright scenes and twilight settings, so by all means use it to get started.
However, you’ll soon find that its maximum aperture of f/4 to f/5.6 is too “slow” for dark-sky shots. Many nightscapes, such as of the Milky Way over a scenic foreground, require a wide-angle lens with a focal length of 10mm to 24mm, and with a maximum aperture of at least f/2.8, if not f/2. The faster the better, as fast lenses also provide a brighter “live view” image to aid in manual focusing at night.
When picking a lens, be sure to get one that will work on your camera. Some lenses are designed to physically attach only to cropped-frame camera bodies. Even if they can be mated to a full-frame camera, their image circle won’t fill the frame, yielding dark vignetting at the corners.
No matter what type of camera you own, acquiring a wide, fast lens will be your best step for improving your images, allowing you to shoot at shorter shutter speeds, for less star trailing, and at lower ISO settings, for lower noise. That last factor alone can help you get good images with older, more noise-prone cameras.
Auto vs. No-Frills Manual
The good news is that fast, wide-angle lenses need not be expensive, as low-cost manual lenses from third-party manufacturers work fine for astrophotography and are much less expensive than auto-focus models.
At night we always need to manually focus our lenses anyway, so the lack of auto-focus is not a detriment. Check for manual-focus models from brands such as Irix, Rokinon (also sold as Samyang) and Venus Optics.
However, if auto-focus is important, I recommend looking at Sigma’s Art series of lenses. They provide top optical quality at a lower price than similar lenses from the original camera brands.
However, the first prerequisite for great astrophotos isn’t having the latest and greatest camera or lens, but to just get out and shoot! Take lots of images, experiment with settings and exposures, and learn what works and what doesn’t. It’s all part of the fun and satisfaction of capturing the sky at night.