I went out to Chiricahua National Monument yesterday to try some sunset photography but got there too late and ended up taking some night images at Massai Point. The moon is at first quarter so I knew I wouldn't be able to get the sort of deep sky images that I enjoy taking but figured it would be a challenge to see what I could get with the moon up. I try to take exposures that are either short enough so the stars in the sky don't smear too much or long enough so they make long trails. Lately, I've enjoyed the short exposure (< 45 seconds) shots so I tried some of those. I wanted to get some of the Chiricahua rocks clearly exposed and found that in the light of the first quarter moon I needed to shoot at a fairly wide aperture to keep the exposure times short. Both of the images shown here have ~35 second exposures taken at an aperture of f/1.6.
I've been pleased with the results I've gotten with my Sigma 50mm f/1.4 lens on my Canon 5D mk II but I hadn't paid close attention to some of the lens distortions that show themselves when shooting star fields. This first image shows a couple of the rocks near Massai point illuminated by the moon and with stars in the background sky.
Look at the top of the image, the stars are distorted so they look like little line segments oriented tangential to a circle centered on the image.
Apparently, night sky imaging at wide apertures requires extremely fine lenses!