Invisible Heavens

Infrared night sky photography holds just as much magic as the visible spectrum does, and there is a certain quintessential quality to it… I need to do more of this!

Pushing the limits of my converted camera to ISO 6400 and the fastest lens I own at F/1.4, this is a two-shot panorama with focus set to the stars. The most difficult part of this image is the focus, because you can’t get it perfect without guesswork.

Infrared light focuses at a different point that visible light. If you rely on a DSLR’s normal methods of focus, an infrared shot will always be out of focus. At F/1.4, the difference can be disastrous. This also applies to manual focus through an optical viewfinder. We’re left with Live view at this point, but there is so little light coming through you can’t separate a star from the noise on the screen. There isn’t enough light to get the focus you need!

The process I used was to set the focus slightly closer than infinity and take a test shot, and taking repeated test shots until I find the perfect spot. It takes a few minutes of guesswork, but the stars weren’t going anywhere.

This infrared image shows false colour, but I didn’t edit the image in my usual manner; there was no channel swapping, which typically gives IR images a blue sky. I simply set the whitebalance to ridiculously cold. This allowed for the natural variations in the night sky to emerge, which I further adjusted and enhanced. Maybe it’s just me, but I think the dark areas of the Milky Way are darker in infrared.

click image for larger version