Today we will look at the three most important settings in your DSLR that are very useful in photography. They are Aperture, Shutter Speed and ISO. A Lens Aperture is Marked on it as a ratio. In this case it is 1:1.8. The 1.8 is the Maximum this lens can open-up. The Blades form an Iris inside the lens. They control the amount of light that is passing through the lens. This lens cannot open up more than 1.8. But you can step it down till 22. You can step it down in steps 2.2..2.8..4… 6… 8… When you increase the F-Stop like that the Iris opening closes down. The more the lens is open which will be your lower F-stops, the more light gets through the lens on to the sensor. The larger F number you use, the less light gets into the sensor.
These series of pics demonstrate that effect. The larger the F number, the less light the sensor gets and less bright is the pic. Also, the larger the F number, more things are in focus. It is called Depth of Field. Less F numbers give Shallower depth of Field. Higher the F number gives more things in Focus. The shallower the Depth of field, the more your subject stands out of background. Light his the sensor and our picture is captured.
One way to control the incoming light is Shutter Speed. Shutter Speed is also shown as a fraction 1/00 = one hundredth of a second. The longer the shutter is open the more light hits the sensor. Fast Shutter speeds lets less and less light on to the sensor. This pics show how increasing shutter speed affects your picture note that the depth of field doesn’t change but the picture gets dimmer. But one thing shutter speed cannot control is flash. Flash is too quick to be controlled by shutter.
Next we will look at ISO. It differs from rest of two As the others are physical control of light hitting the sensor. ISO is adjusting the gain of the sensor to boost the amount of light hitting the sensor. If you look closely at the Zoomed-in portion you will notice grains in the higher ISO. This is noise that is a result of bumping the gain of the sensor.This limits your usable ISO range.