High ISO settings on your Nikon D3300 can result in noise, the digital defect that gives your pictures a speckled look. (Refer to the figure.) Long exposure times (slow shutter speeds) also create a noise potential. To help solve these problems, your camera offers the Noise Reduction filter, found on the Shooting menu.
Before you enable noise reduction, be aware that doing so has a few disadvantages. First, the filter is applied after you take the picture, as the camera processes the image data. For pictures taken at a very slow shutter speed or at a very high ISO, the time needed to finish the noise removal can significantly slow down your shooting speed — in fact, it can double the time the camera needs to record the file to the memory card.
While the noise-removal is in process, you see the message “Job nr” in the viewfinder, and you can’t take any pictures.
Second, although long-exposure noise filters do a fairly good job, those that attack high ISO noise work primarily by applying a slight blur to the image. Don’t expect this process to totally eliminate noise, and do expect some resulting image softness.
You may be able to get better results by using the blur tools or noise-removal filters found in many photo editors because you can blur just the parts of the image where noise is most noticeable — usually in areas of flat color or little detail, such as skies.
Unfortunately, you can’t totally disable the Noise Reduction feature on the D3300. Even when the option is set to Off, the camera continues to perform noise reduction at the level it deems appropriate. (Don’t ask why they didn’t name the settings On and Still On.)
Nikon does promise that the amount of adjustment that’s applied when you turn the filter off is less than what occurs when you turn Noise Reduction on, so that’s something.