We have covered some of the techniques for shooting in low light, so let’s go through the process of capturing a night or low-light scene for maximum image quality (Figure 8.7). The first thing to consider is that in order to shoot in low light with a low ISO, you will need to use shutter speeds that are longer than you could possibly hand-hold (longer than 1/15 of a second). This will require the use of a tripod or stable surface for you to place your camera on. For maximum quality, the ISO should be low, somewhere below 400. The long exposure noise reduction should be turned on to minimize the effects of exposing for longer durations.
Once you have noise reduction turned on, set your camera to Aperture Priority (A) mode. This way, you can concentrate on the aperture that you believe is most appropriate and let the camera determine the best shutter speed. If it is too dark for the autofocus to function properly, try manually focusing. Finally, consider using a cable release to activate the shutter. If you don’t have one, use either the Self-timer mode or Exposure Delay mode. Once you shoot the image, you may notice some lag time before it is displayed on the rear LCD. This is due to the noise reduction process, which can take anywhere from a fraction of a second up to 30 seconds, depending on the length of the exposure.
The basic idea behind the term flash synchronization (flash sync for short) is that when you take a photograph using the flash, the camera needs to ensure that the shutter is fully open at the time that the flash goes off. This is not an issue if you are using a long shutter speed such as 1/15 of a second but does become more critical for fast shutter speeds. To ensure that the flash and shutter are synchronized so that the flash is going off while the shutter is open, the D7000 implements a top sync speed of 1/250 of a second. This means that when you are using the flash, you will not be able to have your shutter speed be any faster than 1/250. If you did use a faster shutter speed, the shutter would actually start closing before the flash fired, which would cause a black area to appear in the frame where the light from the flash was blocked by the shutter.