© Juzo Iwaki SIGMA 14mm F1.8 DG HSM | Art Impression Shooting stars

"This is the lens we would like you to test this time," said a SIGMA representative putting a fixed-focal 14mm lens on the table. It feels big and hefty. The presence is outrageous, but it's convincing because the F-number 1.8 is outrageously fast. After feeling overwhelmed by the enormous front element, I came back to myself to ask them a question. "I wonder what people shoot with this lens." "Let's see. Stars?" "Stars. I see!" I answered as if I were an expert in shooting stars even though I hadn't shoot them seriously. Stars, huh.

© Juzo Iwaki

So, I decided to shoot stars. While there're many kinds of photos of stars, I can use only one lens this time. But, I can take it easy because my job is to demonstrate that even someone with no prior experience in shooting stars can shoot beautiful images with this lens. Of course, I won't(can't) use the equatorial telescope. So, one goal is to find out the lowest ISO sensitivity for the slowest shutter speed that stops the stars. Another goal is how to compose constructions and landscapes utilizing the angle of view. Everything else will be determined at the location.

© Juzo Iwaki

I headed to Nagawamachi, Nagano-prefecture. They say it's a sacred spot for stargazers. It was around midnight. After setting up the tripod (this part was so hard: getting to the point from the car was a pain because it was all dark in the location and I couldn't use my lighting device), I started my experiment. First, I tried to find out the slowest shutter speed that stops the stars at wide open because I wanted to keep the ISO sensitivity as low as possible. While they moved at 30 seconds, they barely stopped at 15 seconds. It looks like 15 seconds is the borderline for the focal length of 14mm. Accordingly, the ISO sensitivity for 15 seconds and F1.8 must be between ISO 800 and ISO 1600.

© Juzo Iwaki

At ISO 800 to ISO 1600, we can obtain the high image quality. Isn't it amazing? In order to get the same exposure with an F4 lens, the sensitivity has to jumped to ISO 6400. Or even with an F2.8 lens, I need ISO 3200. I don't have to repeat about the negative impact of higher sensitivity on image quality here. Being "one F-stop faster" works!