When cost, time, and effort are invested into a photography trip, generally only the best-available gear (or something new being reviewed) makes the pack. Milky way and aurora nightscape photography opportunities were on the potential list for a recent trip, and my three favorite night sky lenses were packed specifically for these subjects.
When the milky way is visible, the scene is extremely dark. While the milky way exposures are long, the earth is rotating, creating a form of action photography.
The aurora has varying intensities and can be pulsing and dancing around the frame. If the exposure is too long, the dancing and pulsing aurora turns into a big smear of color. Thus, aurora photography also involves action, an action that is often moving considerably faster than the earth's rotation.
Wide apertures are a big advantage for stopping action, and each of the lenses included in the above list is the widest available at its respective focal length. Just because a lens has a wide aperture does not mean that you want to use that aperture, as many wide aperture lenses are not sharp wide open, becoming considerably sharper as they are stopped down. However, those in the above list are outstanding performers wide open.
While the f/1.4 aperture is a clear advantage held by the FE 24 over the other two lenses, f/1.8 is still very wide. Motion blur is caused when subject details cross over pixel wells on the imaging sensor. Because the 24mm focal length magnifies subject details more than the 14mm and 20mm options, a slightly faster shutter speed is required to photograph the same subject at the same distance with an equivalent amount of motion blur. This shutter speed difference offsets some of the aperture difference.
Mostly, I selected between these three prime lenses based on the angle of view they provide.
The day started with a 5:30 AM alarm and a long search for moose. Upon returning late morning, we learned that the northern lights forecast was favorable. However, the weather did not appear to be favorable, with heavy cloud cover promising to block all higher altitude subjects. Still, the National Weather Service hourly forecast showed the skies expected to clear at 2:00 AM at our desired viewing location. That time coincided with the moon setting, yielding darker skies.
After a short nap, a 2-hour drive ensued, heading north for darker skies and a favorable viewing location. Intermittently checking the skies, the clearing began right on schedule. Unfortunately, the aurora was not yet apparent to the eye. Dim northern lights are considerably easier to see in a long exposure image, so cameras were mounted to tripods and put into action. Test images showed a small vertical column forming over Denali, the mountain in the bottom of this image.
Initially, the northern lights were small, muted, and stationary. The 24mm lens made the little show larger in the frame than the other two lens options, and also accentuated Denali in the foreground.
The show progressed, significantly increasing in intensity and motion, with this image requiring only a 4-second exposure at f/1.4 and ISO 2500. Eventually, the 20mm angle of view (sample here) was needed to take it all in, and the 14mm angle of view (sample here) became optimal not long afterward.
We pulled into the driveway at 6:30 AM. Aside from a short nap and a few eyes-closed rests, it was a 25-hour day. As is usually the case, I struggle to remember the details of the exhaustion, but the memory of the dancing northern lights is still clear, and the images will last a lifetime, keeping the memory alive.