The short answer
For wide-field night sky photos, a good starting point is a wide-angle lens, roughly 14 to 24 mm on a full-frame camera, with a maximum aperture of about f/2.8 or wider. That combination gathers plenty of light while keeping exposures short enough to avoid star trailing. Specific models change often, so this article focuses on what to look for rather than naming a single winner.
What kind of lens for night sky photography?
It depends on the subject.
- Milky Way and landscapes: a wide-angle lens, to include foreground and a big part of the sky.
- Constellations: a normal to short telephoto lens works if you want a tighter view of patterns such as the famous constellations.
- Deep sky objects, the Moon and planets: these need longer focal lengths, and usually a tracking mount or a telescope (see astrophotography with a telescope). See how to photograph through a telescope with a phone for an easy start.
Focal length
Wider lenses allow longer exposures before stars trail, and they capture more of the Milky Way. Longer lenses make stars trail sooner, so exposures must be shorter. This is why many people reach for 14 to 24 mm lenses.
Is a 14 mm lens good for astrophotography? Yes, a 14 mm lens on full frame is a popular choice for Milky Way scenes, since it takes in a wide area and allows relatively long exposures. The trade-off is that stars are smaller in the frame, and some ultra-wide lenses show edge distortion. Whether it suits you depends on how much sky you want to include.
Aperture
A wide maximum aperture, such as f/2.8, f/2 or f/1.8, lets in more light (the same idea as focal ratio in telescopes), so you can use a lower ISO or shorter shutter speed. Faster lenses are usually larger and more expensive. Even a fast lens often looks sharper when stopped down slightly, so test yours at its widest setting and one stop narrower.
Optical quality
Night photography reveals optical flaws that daytime shots hide.
- Coma: stars near the corners stretch into wing or comet shapes. Some lenses control this well, others less so.
- Vignetting: darker corners are common at wide apertures. It can be corrected in editing, but that brings out more noise there.
- Sharpness across the frame: stars show whether the edges are as sharp as the center.
- Chromatic aberration: color fringes around bright stars.
Reviews and sample images taken at night are more useful than daytime test charts. Look for photos of stars in the corners at the aperture you plan to use.
Crop sensors and focal length
On APS-C cameras the field of view is narrower than on full frame because of the crop factor (often about 1.5x, or 1.6x on some brands). Micro Four Thirds has a crop factor of about 2x. Divide the full-frame focal length you want by the crop factor to estimate what you need. Crop factor also matters for shutter speed rules, as described in our night sky photography guide.
Manual focus and build
You will focus manually, so a lens with a smooth focus ring, and ideally a focus scale, helps. Autofocus matters little for stars. Weather sealing is useful in cold or damp conditions.
Prime or zoom?
Primes usually offer wider apertures and sharper results for the price. Zooms are more flexible for framing, especially f/2.8 zooms, but are heavier and often cost more. For beginners, a single wide prime is a simple starting point.
Budget options
- Your kit lens. Typical kit lenses are slower, around f/3.5 to f/5.6, so you will need a higher ISO or shorter exposures. They can still work for bright constellations.
- Manual-focus third-party lenses are often inexpensive and fast, and are popular among night photographers. They lack autofocus, which does not matter for stars.
- Used lenses can be good value. Check the condition and, if you can, test for sharp stars at the edges.
Checklist
- Focal length suited to the sky area you want (about 14 to 24 mm full-frame equivalent for the Milky Way).
- Maximum aperture of f/2.8 or wider.
- Acceptable coma and edge sharpness, checked in night samples.
- Smooth manual focus.
- Fits your camera mount and budget.
Pair your lens with sound technique. See the night sky photography guide for starting settings, or try star trail photography with the same lens.