Wide Angle Lenses
For Landscape and Astro-photography, "wide" is a necessity in order to capture as much of the scene (or night sky) as possible. While 35mm was once considered the standard "wide" landscape lens, 14mm is now common. Used correctly, 14mm does not produce the 'fisheye' image once associated with focal lengths shorter than 20mm.
Banner image: "Milky Way over Arch Rock, Joshua Tree" - was taken with a Sony a7r II Full-Frame camera using a Rokinon 14mm F2.8 lens. The image was created as a vertical panorama consisting of nine vertical images.
The panorama was generated in Lightroom CC.
WHY GO WIDE?
For Milky Way photography, the focal length of the lens determines how long you can leave the shutter open before the stars start blurring in the final image - see the 500 Rule. For 14mm lenses, you can leave the shutter open for 35 seconds which is essential for the standard 'nighttime' exposure of ISO 3200 @ F2.8 for 30 seconds.
Modern full-frame cameras produce images at 6k to 8k resolution, With a wide lens, you can record more usable information in the scene at very high quality.
For landscape photography, wide lenses allow you more freedom when composing your scene, including the ability to move closer to a critical element (a tree or rock) while still retaining your overall composition in the frame.
Can't I just make a "Panorama" with my standard lens?
Standard lenses are not optimal for panorama photography. 1) You are required to take many more (2x) images for the pano, resulting in increased distortion. 2) "Vertical Panoramas" are the norm now - and standard lenses provide minimal coverage in the vertical format.
HERE ARE SOME OF MY FAVORITE WIDE LENSES
Note: For Astro-Photography, "fast" F2.8 lenses are required.
Note: Check out the volume of ratings on these lenses on Amazon.
NIKON 14-24MM F/2.8G ED ZOOM
This the premiere landscape and astro-photography lens. Indeed, you will frequently see it attached to Canon and Sony bodies. It is sharp edge-to-edge and the chromatic aberration is minimal. This lens is designed for full frame cameras.
ROKINON 14MM F2.8 ULTRA WIDE
Rokinon has produced a stellar 14mm lens and they offer it at an affordable price. This is a manual focus, manual aperture lens, but you generally just keep it set to infinity - even at F2.8 (night-time photography), objects as close as 5 feet from the lens remain in sharp focus. This lens is designed for full frame cameras, but will work with smaller sensors. Rokinon produces versions of this lens for all major camera manufacturers.
TOKINA 11-16MM F2.8
Tokina has produced a great 'wide' lens for non "full frame" sensor cameras. The lens is very sharp, and the images are very clean. For a 1.6 crop factor - this lens is the equalivent of a 17-25mm lens.
CANON EF 16-35MM F/2.8L III LENS
This Canon lens (and Version II as well) is a great all around lens for astro and landscape photography. It is sharp and clean. V III brightens up vignetting in the corners and improves the overall optics. 16mm is plenty wide!