Is there any escape from noise?
Digital night photography with Canon digital SLRs is constrained by exposure times of approximately 6-8 minutes without noise reduction. For most cameras, turning on noise reduction in the camera effectively cuts your productivity in half, because noise reduction takes the same amount of time to run as your exposure (i.e., a 15 minute exposure necessitates an additional 15 minutes for noise reduction to run, for a total time of 30 minutes). Noise reduction can be performed in post-processing, but I've found in-camera dark frame subtraction to be superior.
Before the recent rise of the digital SLR, medium format film cameras were often the tool of choice for night photography. For many night photographers this still holds true. Due to longer focal lengths, and film reciprocity, a standard full moon exposure for medium format film can often run in the 15-20 minute range at f/8. With clear skies, a 15-20 minute exposure produces a star trail length that hits a personal sweet spot for me. I will often push the Canon 5D into the 10-12 minute range to get longer star trails. With noise reduction this ties up the camera for 20-25 minutes per shot, giving you shorter star trails than film, and less productivity.
One tactic that has always seemed like a great idea is to bring two kits into the field -- a digital SLR and a medium format film camera. A digital SLR allows quick exposure testing, and the instant feedback on shots with light painting. A medium format film camera can be setup for 20 minute or longer exposures on shots where longer star trails would be aesthetically pleasing.
The only problem with this idea is you better have a great chiropractor. Carrying 2 camera kits into the field with 2 tripods can get ridiculous. If you're working close to the car, and have reasonably light camera kits and tripods, it's certainly doable. This was my plan last week in the Mojave, but cloudy conditions with mixed lighting meant that 20 minute exposures were unnecessary -- for the most part, there were no stars to make trails.
A Cloudy Night
I brought both camera kits and one tripod into the field. The 5D with a 24-70/2.8L lens was carried on the tripod, and a Mamiya 7II with a 50mm lens in my backpack. After exposure, composition, and lighting were nailed on the 5D's LCD screen, I'd shoot from a similar camera position with the Mamiya. Digital exposures were 2-3 minutes at f/6.7 ISO 200, and film about 6 minutes at f/8 with Kodak E100VS film.
Exposure times of 1-3 minutes are often a good range for capturing cloud movement at night. Longer exposures will often just blur out the sky and look flat. Had the sky been clear, I would have shot at 6 minutes f/6.7 or 8 minutes f/8 at ISO 100 with digital for star trails.
Digital Night Photography: Camera Settings
Exposure testing is extremely fast and convenient with the 5D. The camera is preset in "M" mode for an exposure time of 6 seconds at f/2.8. I bump the ISO to 1600, take a test shot, and assess the histogram. This exposure time equates to 4 minutes at f/6.7 ISO 200, or 6 minutes at f/8 ISO 200. If the histogram looks right, change the ISO back to 200, and switch to "B" mode -- which will still be set at f/6.7 from your last shot -- and make your next exposure.
Here are a few tips:
- Setting your camera to half stop exposure increments makes exposure calculations much easier.
- A Canon TC-80N3 timer remote (or equivalent) is a must. You'll wonder how you lived without it.
- With the 5D, I preset my camera in "B" mode to f/6.7, and in "M" mode to 6 seconds at f/2.8. I'm ready to shoot in "B" mode, and ready for exposure testing in "M" mode. All I need to do is change the ISO, and then start the timer remote when I want to open the shutter.
- Set your LCD brightness to the darkest setting. A bright LCD will screw up your night vision.
Medium Format Film
Night photography exposures with a film camera require getting to know different lighting conditions and film emulsions. Kodak E100VS and Fuji RTP Tungsten are my favorites for night photography. Black and white shooters need look no further than Fuji Acros, the king of reciprocity and fine grain for night shooting.
The Mamiya 7II has a clear, bright viewfinder, and extremely sharp wide angle lenses. While there are some complaints about the depth of field scales being overly optimistic, I've found the scale on the 50mm lens to be reasonably accurate. This lens equates to about 25mm focal length in 35mm terms, which is my personal preference over the also stunning 43mm lens, which equates to 21mm. If you are used to SLR zoom lenses, the optical performance of the Mamiya wides are bitingly sharp in comparison.
Unlike fully mechanical cameras like the Hasselblad or Mamiya RB67, the Mamiya 7 is battery dependant. No battery = no photos. A lithium battery is supposed to give you 8-9 hours of operation, and costs about $9. Bring a spare.
While I've shot extensively in the 6x6 format, and also a bit in 6x9, i've never owned a 6x7 camera. I'm finding the aspect ratio to be extremely pleasing for both night and day photography. The 2:3 aspect ration of 35mm works well for me in landscape format, but has always seemed too narrow for verticals. Perhaps 6x7 really is the "ideal format." Of course 35mm shots can be cropped -- I'm not a purist about cropping, but I don't tend to crop very often.
Below is the 6x7 film version of the same shot posted above (both in landscape format). I've pushed the digital RAW file a bit to bring out the blue and orange mix/saturation. The film version is pretty true to how it looks on the light table. Which one do you like better?