Your tolerance for noise

The idea of this exercise is to check out the range of iso on my camera and also to look at the amount of noise and how it affects a photograph as the iso gets higher.

I use a nikon D300s and the range of iso on that camera is between 200 and 3200 but with the option to go three 1/3 ev stops either way in special conditions.  I decided to include these as well in the exercise and picked an aperture of F5.6 and began taking the photographs, as this exercise needed to be indoors and I had no white walls I finally settled on using my backdrop with a small red chair and teddy bear on it. This way I had some sharpness in the form of the chair to look at plus the white backdrop and also I thought it might be interesting to see how the 'fur' of the teddy bear reacted to the higher iso.

Above is the range of my camera, the one photograph came out very dark the only thing I can think of is that the sky clouded over slightly more for a second.
Having looked closer at the photographs I could see that there was no noise until the iso got to about 800 from there it started to get progressively worse, and by the time it reached the highest iso on my camera the effect was so bad it would render the photograph useless, not only could you see the deterioration in the white background but also in the chair and  it was very evident   in the fur of the teddy bear where there was some much noise the detail was lost.

these two photographs show there is no noise present in the lowest iso which is probably about iso 75 at a guess.

the three photographs above are the highest iso in my camera's range, I have included the photograph of the bear as I think the noise is clearer in this photograph than the one above.

ISO is also the third way of adjusting the amount of light that is let in, after the aperture and shutter speed, sometimes using a high iso and getting noise can add to the image, for example a band photograph might like the slightly 'gritty appearance'.

Interestingly I brought the April edition of Practical Photography and in it was an article on iso and grain they also had three photographs of coloured pencils at various iso settings which gave me another example to look at, they also go onto say that sometimes noise can be used as an effect for example on some black and white work.

So what have I learned from the exercise? I have learnt that you can adjust the iso and it can be a useful tool to use, sometimes to a great effect but I have also learnt that there is very often a trade off when using a very high iso, I think the motto is don't be afraid to alter the iso when the need is there but use it wisely.