Sharp low-noise photography using multiple photos

Step 2 Configuring the camera

So, every time you take a picture, you get some noise.
When shooting dark scenes, and use a high ISO speed (sensor sensitivity) it is very visible,
while it is almost impossible to find on well lit bright pictures.

This noise does not look the same on each photo you take,
so by taking multiple photos, you can just find an average color for the same pixel on each image.
In that way you can get closer to the "actual" color.

So... Find yourself a subject with the right lighting for this experiment. I just chose a bunch of books in my room, lit by 2 windows with an overcast sky outside, right after sundown.

If you have "exposure compensation" on your camera, and don't want to learn how to do this manually, just find the =!= and read on from there.

Make sure your camera is set to "green automatic". Frame your subject and take a shot.
Is the result blurry or noise? Good... Find the info for the newly taken picture on your camera. You need 2 numbers: shutter speed and sensitivity.

First number is often a fraction, like 1/30 or 1/2, or maybe just a whole number, like 1 or 2 (often displayed like 1" or 2") The other number can often be divided with 100 or 25.

Exposure time / shutter speed:

16" 8" 4" 2" 1" 1/2 1/4 1/8 1/16 1/30 1/60 1/125 1/250

ISO speed / sensor sensitivity:

100 200 400 800 1600 3200

Each of these numbers are "full steps". Your camera will step in either 1/2 steps or 1/3 steps.

The numbers can therefore also be for example:

Exposure time:

1,3" or 1,6" between 1" and 2" at 1/3 step, or 1,5" at 1/2 step

125 or 160 between 100 and 200, at 1/3, or 150 at 1/2 step

Now you know what settings will give the right exposure.

We will be combining 8 photos in this instructable, each with 1/8 the needed brightness.
As you have propably noticed, each step on the above scales are either half of, or double of the previous, depending on in which direction you're moving on the list above.
So, we need to step down (go to the right) 3 times. This can be done with either shutter speed, ISO sensitivity, or a combination.

Go for shutter speed as first priority.

Find the "manual" mode on the camera. Dial in the shutter speed and sensitivity found earlier.
Now, step these settings down 3 steps. That is pressing down 9 times if your camera uses 1/3 steps, and 6 times if it's 1/2 steps.

=!= The easy way

Find "exposure compensation" on your camera. If you don't know where to find it, look in the manual.
Set this to "-3 EV" this will take the picture 3 steps lower than what the camera otherwise would find suiting. Here you can not really control the settings, the camera will choose sensitivity and shutter speed.