Exercise: Your tolerance for noise.

Outline: Using a scene with the following criteria:

• Daylight indoors
• A combination of sharp detail and textureless area

set up a tripod and take a series of identical photographs, changing the ISO setting from one to the next.

Being completely honest, I haven't had fun completing this exercise. I've taken numerous different shots as I expected the outcome to be a lot different than it has on all attempts.
This is the set of images that I took in ISO setting sequence:

My camera has 5 ISO settings: 100, 200, 400, 800 & 1600 (seen here in order). I took photos of a toy box against a textureless wall where some shadow could be seen and have cropped the image to highlight just the shadowed areas.
With aperture priority at F22 the shutter speed fluctuated from 6 secs at ISO 100 to 0.40 secs at ISO 1600.

Looking at the images altogether, there doesn't seem to be much difference between them. And this was the outcome with the other 4 attempts of taking these images.

If there are any comparisons to be made here, I will state that the higher the ISO settings, the more grain you can be seen in the images although the actual shadow area seems a little lighter making the contrast slightly less.

Conclusion: I have had previous experience with noise appearing in images where I have needed to use a high ISO setting, it's just i haven't really shown a great example through the images for this exercise.  Looking at this image I took during a festival in the summer and used for my final assignment in The Art of Photography;

The image was taken in a stage tent during the day and so I needed a high ISO setting. The grain in the image is very noticeable through the artists skin, hair and even the background area. This is a prime example of noise that is not real detail and is purely due to the high ISO setting.