Long exposures and the problem of noise

One of the big problems with digital cameras and long exposures is noise: in long exposures, for example at sunrise or sunset, the shutter often needs to be open for lengthy periods of time. This can be 15, 30 seconds, or many minutes. What happens then, however, is that the camera sensor begins to introduce noise into images – it seems to me that this is often especially visible on “flat” or even surfaces, such as still water (and water then loses the glassy look that makes such images work so well). This noise can look a little bit like grain on traditional fast film. Most digital cameras have a noise reduction “feature”, but it is best left turned off, I think: these usually work by mushing up the pixels to reduce noise. What you get is an image that looks poorly focused – which just defeats the object of taking the photograph in the first place.

So what to do?

I’ve been going through a number of the images that I took on Mull this summer using Fuji Velvia 50 slide film (I plan to add some of them to my website soon; all the Mull ones that are online just now are from the digital camera). Many are taken using longer exposures and there is – of course! – no noticeable noise/grain, even on the longest exposures. So rather than worrying about how to solve the noise problem on my digital camera, for now at least, I think I’ll just stick to Velvia and my old film camera for the long exposures.

(Note that this post doesn’t even attempt to touch on all the other issues that relate to image quality when discussing the digital/film issue, I’m just focusing on noise… clearly, Velvia, properly used, is immeasurably superior to most digital cameras)

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