ISO and Noise test

 ISO is used to figure out cameras sensitivity to light controlling the sensitivity of the sensor.  An obvious reason for the use of higher ISO's is so that it can be possible to take photographs in low light without having to have an extended shutter speed. Noise can sometimes be seen within an image when higher ISO is used in digital photography. Signals are produced when light hits the cameras sensor; some of the signals become distorted and change the result of the photograph. Noise can be seen when some of the pixels in an image changes colour.

 I wanted to do two different tests to see how my camera reacts to different ISO setting. Firstly I found a space in my house with very little light and took 5 photographs changing the ISO setting on each photograph. I used a tripod as I had to use long shutter times and wouldn’t have been able to keep the camera still hand held. I kept the shutter speed at a constant 20 seconds and aperture at f3.2. I carried out this test to see how the ISO setting would affect the sensitivity of the cameras sensor.

I am happy with the results I have got from this test because it is clear to see the effect that the ISO setting has on an image. It amazed me that the only variable was ISO and that the shutter speed and aperture were both constant, I have learnt that changing the ISO can make a big difference to what is captured by the camera.

I then went on to perform the 'noise test'. Like the ISO test I also had to find another low-light area where I could set up my camera on a tripod. This time because I already knew the effectiveness of the ISO I was able to alter the shutter-speed from picture to picture. I was now able to control the light levels throughout the images so that it would be easier to compare them with regards to noise levels. . This test is done to see how well the higher ISO settings on the camera work.

The outcomes of these images are very clear. I found that the picture on the lowest ISO is much clearer and cleaner compared to the higher ISO which is left with a lot of noise and distortion. As the ISO level was increased, the shutter-speed was decreased to help the additional sensitivity work well. The shutter-speeds were declining in the same fashion, each speed being halved. I also found out that although a higher ISO speed produces a much noisier photograph, it allows an image to be taken in an area with less light at a higher shutter-speed, this is helping this images becoming blurred caused by movement.