Someone just asked me this question:

I just bought a Nikon D80 and wanted to know how do i reduce the “noise” In the photos? Everything that I take over ISO 400 has lots of noise.

I figured it was a good time to document my workflow. I’m not an expert on this topic… I’ve mostly been fooling around and experimenting. Sadly, it has taken a lot of fooling around and experimentation to get shots I’ve liked.

I shoot almost exclusively at ISO 800. I tend to favor aperture priority for the camera setting (although in some real bad situations I go full manual) and in low light I shoot with a 50mm f1/8 lens usually cranked down to f1/8. For long shots i have an 80-200mm f2.8 lens (Nikon 80-200/2.8 D-AF ED) although in really dark situations this lens is too heavy to shoot with freehand.

I shoot in Raw mode. I do all my post processing on Linux using F-Spot, ufraw and gimp. Getting results that are worthwhile has been a struggle with these tools, but mainly because i needed to know what I was doing and I didn’t ;-)

To get decent results with UFRaw I found i needed to do several things. First, I needed to tell ufraw about the Nikon camera’s color profile. You can download color profiles and set them up in the tool. I generally use the camera’s white balance, but will tweak this on occasion to get the colors closer to what I wanted. I don’t like to to goof with correcting the exposure much in software. I much prefer to get the exposure close to right when I take the original shot. I think this has a huge amount to do with avoiding graininess and getting sharp pictures.

You will need to do some noise reduction in software when converting your images from raw to JPEG. I use AHD interpolation with an Threshold of 150 for really noisy pictures. I played around with these settings until i could get a pic that looked as close to the JPEG generated by the camera itself. (You don’t need to shoot in JPEG+RAW to do this… see my earlier post for info on this. In the open source photography group there is a nice discussion of the different mechanisms ufraw has for noise reduction. Take a look for more information.

I haven’t resorted to using the dark frame mechanism to further reduce noise. This is mostly useful for very long exposures and since I tend to take pictures at rock shows and of kids, there is way to much activity for long exposures.

What to shoot in? DSLRs have several different choices. Jpeg, Raw+Jpeg or just Raw. Jpeg is a lossy image format. That means that the Jpeg image has lost some of the actual image. In addition, each time you open a Jpeg and save it back more information is lost. The nice thing about Jpegs is that they are relatively small. Raw images on the other hand are large and represent the data sensed by the cameras sensor. Think of a raw as the raw data from the sensor - although in the case of Nikon some data in the raw format is lost as well.

In a situation where you want to retouch, resize crop or edit a picture starting from a raw image is the way to go. You are in full control when working with raws about what data will be lost and how. This basically guarantees that you are going to want to shot with either Raw+jpeg or just the Raw format. After all, if you wanted a point and shoot experience you'd be using a point and shoot camera!

So, the question is Raw+Jpeg or just Raw. If you only shoot in raw you'll need to do some processing on the Raw file to make use of it. Many Raw formats come with preview images embedded in them constructed from the Raw using basic camera settings. Sometimes these images are great and you wont want to do much with them - these are basically just the Jpeg you'd have gotten by shooting in the Raw+Jpeg or Jpeg only mode. There is one big caveat here, not all Raw formats are the same. My Nikon camera stores a full resolution Jpeg image, but Canon cameras store a lower resolution image. If your camera stores a lower resolution image in the Raw, then its probably best to shoot Raw+Jpeg for maximum flexibility - you can find out by checking your vendors page on the ufraw wiki. Otherwise, just shoot raw. You can extract the Jpeg from the raw using ufraw with the --extract flag.

Calibrating your monitor so that the representation you get on the screen closely matches that which you'll get when printing an image is critical to properly retouching an image. I've been really happy with the results from this simple web page.