Last Thursday I was exploring an area of the Bighorn Basin not very far from ny home. The area is called Oregon Basin and contains the largest producing oil field in Wyoming. The field has been producing oil for nearly 100 years. Geologically it’s a breached anticline (fold in the rocks) that trends north/south. The center of the fold has been eroded out over time exposing some great rock outcrops of sandstone in the Fort Union formation. I was looking for interesting rock formations to use as an anchor for a sunset image which would include the mountains to the west and by luck I found a beautiful rock arch. Though it’s not the biggest arch it looks out to the northwest and nicely frames Hart Mountain which is one of the most recognized landforms of the western Bighorn Basin. Interestingly my home is on the southwest flank of the mountain. The first problem is that by using a wide-angle lens you lessen the prominence of Heart Mountain which you can see in the center of the image.
Canon Eos 5DmkII, EF16-35mmF2.8L, F22 3 images bracketed and merged
(click on image to view full size)
To achieve the image I had in my mind the scene presented a real challenge. The biggest problem was the extreme dynamic range of the image. I wanted good detail inside the arch along with a properly exposed sky. The dynamic range of the camera just can’ t handle that. My first thought was to use a graduated ND filter to darken the sky but by doing that I also darkened areas of the arch I wanted detail in. With warm late afternoon light was illuminating the interior of the arch I decided that my best option would be an HDR image, I decided to bracket 3 photos exposed at -2, 0 and + 2 and then merged them in Photomatix. I made a critical area by not paying enough attention to my histogram during the exposure and wasn’t able to get the sky toned down enough.
Canon Eos5DmkII, EF16-35mm F2.8L, F22. HDR 3 shot bracket
(click on image to view full size)
As the sun sank even further in the sky approaching sunset it became visible inside the arch. I envisioned the sun as a starburst and knew by shooting at F22 I could achieve that. Unfortunately I could not overcome the flare the sun produced with this lens. Most zoom lenses have a tough time controlling flare. Again my 3 shot bracket was not sufficient to cover the dynamic range of the image. I’m certain to visit this location again and I will try to overcome the photographic challenges it presents. I think a 5 image HDR bracket exposed from -3 to +2 stops would be adequate. I also need to use a single focal length wide-angle lens to help control the flare. My thought is to try the superb Canon 24mm TSE II lens on this scene. It is reputed to have excellent flare control. My first try wasn’t quite as good as I hoped but I’m sure I can get this image right and you know the very best thing about this location is that it hasn’t been over photographed…..
