意識流隨筆
旅遊寫意
Northern Light (NL) & Photography
The NL intensity depends on both solar activity and the strength of earth magnetic field. Strong solar rain will results a high NL intensity (KP). The third factor determines NL observation is the clouds coverage. High percentage of clouds coverage will make impossible for NL observation no matter how bigger number of KP is. Iceland is one of the best place on the earth to see NL. The NL clouds move across the Iceland sky every night. Because KP is usually 1-2 and sky often is covered by clouds, NL observation still requires lots of luck. We met one couple from Span who said they spent last 10 days in Iceland waiting to see NL without any luck. We have been hunting for NL for 4 nights in the middle nights at temperatures below zero C. Only twice we saw faint NL with help of the camera. The first night at Fosshotel in Myvatn, I was lucky to capture several pictures of NL with KP 2 and 0 clouds coverage. The 2nd time at Fosshotel Nupar with KP 3-4 and 0 clouds, I got better pictures with improved technique using a primary wide angle lens, F2.8, 28 mm and easy adjustable focus (to maximum). When taking pictures of NL in dark, I have to be able to know the focus stay on maximum and F 2.8. Also I sometimes forgot to take off lens cover. After taking many pictures and just realized the cover is still on. To avoid this mistake, leave the LCD on the camera open every time you start shooting. After each picture is taken, the image will show on the LCD. You can then close the LCD to save battery.
Camera Settings (F 2.8 or the lowest the lens allowed)
SETTINGS ARE DEPENDENT ON THE NL STRENGTH
NL Strength: 2-4 (NL moves slowly, low intensity)
ISO: 2000-2500, speed: 6 to 10 seconds
NL Strength: 4-5 (NL moves slowly)
ISO: 400 speed: 10 seconds (NL moves slowly)
*** The tour guide said he never use ISO higher than 400 with F3.5
NL Strength: 4-5 (NL moves slowly)
ISO: 800 speed: 6 seconds (NL moves quickly)
*** I use ISO 800, speed 6 second & F2.8 to capture fast moving NL (KP 5)
