Nikon D200 Noise at Long Exposures

The table below shows a series of dark frames with different exposure time and sensor sensitivity, taken at about 20 degrees room temperature. The camera settings were: (optimize image = normal, long exposure noise reduction = no, image quality = fine, white balance = direct sunlight). Except for scaling no image treatement was done. Between each exposure there was enought time to let the camera cool down. The camera was put into a dark room to prevent light getting through the finder or bajonet. Compeare also the tests about Nikon D70 sensor noise.

One can easily see that the due to heat of the electronics the corner of the images get pink bright. Some spots on the right hand picture side are interesting.

ISO 100 ISO 200 ISO 400 ISO 800 ISO 1600
1 min 1m @ ISO100 1m @ ISO200 1m @ ISO400 1m @ ISO800 1m @ ISO1600
2 min 2m @ ISO100 2m @ ISO200 2m @ ISO400 2m @ ISO800 2m @ ISO1600
4 min 4m @ ISO100 4m @ ISO200 4m @ ISO400 4m @ ISO800 4m @ ISO1600
8 min 8m @ ISO100 8m @ ISO200 8m @ ISO400 8m @ ISO800 8m @ ISO1600
15 min 15m @ ISO100 15m @ ISO200 15m @ ISO400 15m @ ISO800 15m @ ISO1600
30 min 30m @ ISO100 30m @ ISO200 30m @ ISO400 30m @ ISO800 30m @ ISO1600

The picture belo shows a dark frame of 30 minutes exposure time at ISO 400. Interesting are the few spots on the right hand side. They rather look like defects of the sensor than coming from heat. At "normal" exposure times these spots are not visible.