Whilst I have shot the Brisbane city skyline at night many times before, this week I wanted to test the performance of my Canon 40D in regards to ISO settings. This post will be about how to test the ISO on your camera. These types of test are a great way to learn the limits your camera has so that when you are out in the field you can select the best settings for your gear.
The ISO performance of cameras is being dramatically improved with each new camera release. At the high end of the Canon range a 5D Mark 2 can perform very well around ISO of 3200. On my 40D I try not to push it past 800.
For the test I had the camera in Manual mode and set an aperture of f/16. I then compensated for the change in ISO with the shutter speed. I have decided to only test the ISO’s performance for full stops of light steps. The lowest ISO for my 40D is 200 and this is where I usually try to shoot. I then moved to 400 and then 800. The below image compares the 3 shots. There is certainly a noticeable difference between the 200 and 800 shots in the sky. The water is also much more silky smooth the the ISO 200 shot. This is due to the fact that the exposure was 4 times longer then the ISO 800 image.
There are some great software packages available on the market for reducing the noise. Some of these tools have plugins to most the mainstream graphic processing programs. I personally use Noise Ninja.