Why to Keep the Camera ISO Low
In understanding why to keep the Camera's ISO low, it would first be helpful to understand the ASA of film stock. ASA is a system used to measure how much light is need to expose an image. The higher the ASA rating, the more light you need. Lower ASA film stock opened up new possibilities for people working with tighter budgets, but it does not look as good as it's higher ASA counterpart. Instead it looks grainy and not as crisp. ISO causes the reverse effect in the digital world.
Your camera's ISO is similar to film ASA except, the lower the ISO the less grainier the image. If you want the best looking pictures possible then leave your ISO setting low. However, this is not always practical. There will be situations where your aperture is opened as far as it could and you still don't have enough light. The only options then are to raise the ISO or have a picture where you can't see anything.
Since the ISO is so important to the quality of the image, especially in consumer cameras with small image sensors, as a rule you should always open the aperture before raising the ISO. A shot with a wide open aperture and low ISO looks better than a shot with a closed aperture and high ISO.Popular Cameras for High Quality Photos: