Most cameras normally come with exposure mode automatically set. This allows you to just go ahead with photography as your camera is already set to select settings for you. This helps especially when one is a beginner but as you progress in photography, you will desire to have some clear and crispy images which might not be possible to attain with the preset exposure modes. Moving on to semi automatic modes provides you with more room to explore and with proper practice you will be able to effectively master how you can set the exposure triangle effectively to be able to realize the desired images. Mastering the exposure means understanding the amount of light allowed to hit the sensor of the digital camera when you press the shutter button, which is very important.