Milky Way Over Arches

UPDATE: Here's an updated version of the shot, taking into account the feedback I got here. I think it's much better now, thanks! See my comment down below for what I changed, or just take a look.


My first NPN post! Decided to give the 30-day trial a shot, since the articles/galleries/critique all seem to be of a much higher quality here than on other free sites.

This is Double Arch under the Milky Way. Arches National Park, Utah, October 2011. The main arch is 104 feet tall, and 148 feet wide.

I don't usually bore people with the details of how a shot was made, but I get a lot of questions about this one, so:

Foreground exposure: ISO 400, f/4, 7 minutes, 6500K WB
Sky exposure: ISO 3200, f/2.8, 30 seconds, 4200K WB
Canon 40D, EF-S 17-55mm f/2.8 @ 17mm

I painted the arches with an LED flashlight while lying down behind the lower-center rocks - I wanted back/side lighting to bring out the texture in the rock. I also had to experiment with how long to spend on each arch/edge, as they were all different sizes. I ended up spending over half the exposure painting the main arch, and split the rest of the time amongst the other edges and the background arch.

The warm foreground WB was used to compensate for the fairly cool LED flashlight color, to try to restore their natural red hue. I hand-blended the two exposures in PS with masks, and cloned out a light trail my flashlight left at the bottom of the frame.

I could have done this in a single frame if I had a warm gel for my flashlight, and a body like the 5D2/D700, where I would have been happy with the foreground quality at ISO 3200. However, the longer foreground exposure ended up working in my favor, as the lighting appears smoother with the painting spread over more time. As it is, I'm surprised at how well the 40D did on the sky - but it did take some significant noise reduction.

The desert can be a bit scary at night alone (particularly with signs warning of mountain lions) - but well worth the photographs.