To Reduce Noise or Not?

I was going through the various menus of my camera and realised that I have the option of switching Noise Reduction on and off. Since, noise is usually undesirable, so shouldn’t we always keep this feature switched on? Why does the option to switch it off exist in the first place?
Ramesh Shah, Vadodara, via e-mail

This story was originally published in October 2014.

Sometimes, you may wish to switch off incamera noise reduction and use the grain to your advantage. Photograph/Raj Lalwani

Noise is a phenomenon that often occurs in digital photos, while shooting at high ISO settings. It may resemble film grain or may look like coloured splotches distributed all over the image. In ordinary circumstances, it may seem as if noise is undesirable, which is why we have the option of reducing it within the camera. However, there are a number of compelling reasons why you may want to keep Noise Reduction (NR) switched off instead.

Firstly, the in-camera Noise Reduction feature in most cameras does a rather shoddy job. It smoothens out the noise in the picture, thus reducing the amount of detail recorded as well. The amount of smoothening, too, is automatic and cannot be controlled much. This is why you may wish to switch off NR, so that you can perform the same task in a software, to get better results. In addition to this, the use of Noise Reduction often slows down the camera. For example, if you are shooting a 10sec exposure, Noise Reduction will cause the camera to freeze for a further 10 seconds even after the exposure is over.

Finally, there are some situations in which a clean, smooth look may not be ideal. You may wish to add a grainy look to your photograph, especially if you are shooting in black and white, to add a sense of mood, grit or texture.