An ISO can make or break a picture. Changing the ISO can change the sensitivity of the image sensor. To put it simply, setting a higher ISO raises the shutter speed and reduces the aperture value to let less light hit the sensor. The lower the ISO, the less sensitive the sensor is to light. Similarly, the higher the number, the more sensitive it becomes. That comes in handy when shooting in variable lighting conditions. It's particularly beneficial when the light is low, but you don’t want to spoil the mood of the picture by using a flash. That's an example of when you can increase the ISO and compensate for low light. The only problem with that is there would be more "noise" or "grain" in your shots. Yes, the higher the ISO, the grainier your picture will be. Therefore, the best rule to live by is to choose the lowest ISO possible for smooth shots.

So, without further ado, here are a few guidelines you can follow to choose the right ISO for your photos:

1.) When you're using a tripod, use a slower shutter speed. That will allow you to lower your ISO.

2.) If you don’t need a large depth of field, increase your aperture and allow more light into the camera. You'll then be able to lower your ISO.

3.) Using a flash will help you decrease your ISO setting as well.

4.) Bump up the ISO if you're into abstract photography and you need a grainy look to give your pictures mood and a certain character.

5.) If you're not planning to blow up the picture, you don’t have to worry about graininess. You can increase the ISO as much as you want.

6.) You can change the ISO only if you're shooting in manual or semi-manual mode. If you have a camera with preset modes or you're opting for the auto mode, you don’t have to bother with changing the ISO, because the camera picks the lowest ISO for you at that particular setting.

7.) In cases where your picture conveys the right mood, but has a lot more noise, you can salvage that photo by playing around with a free tool called ND Noise. Other tools can be found by doing a Google search for "Noise Reduction Software."

8.) If you're photographing fireworks, shoot them at an ISO of 3200.

9.) Many times, you'll end up changing the ISO for one photo shoot and you won’t remember to change it back to its default position later. Therefore, it's best to write yourself a note and put it just below the viewfinder so that you see it every time you're doing a shoot. Another way is to try and shoot in manual all the time. That way, you're more likely to check the ISO when you're adjusting the aperture and shutter speed.

10.) One rule of thumb to go by is to always set the ISO to the lowest number possible. Start with ISO 80 for bright conditions and 100 or 200 for darker conditions. You can then increase it, if necessary. Photographers rarely shoot at ISO 400 and above for fear of more noise. However, if you're dealing with tricky light conditions, select the aperture priority mode and adjust the aperture and ISO accordingly.

11.) Another handy rule is to try different ISO settings all the time when you take pictures. Try several different shots with different ISOs so that you can choose the propecia normal dosage best of the bunch. With practice, you'll get better at finding the best ISO for the light conditions you have to work with.

12.) Graininess becomes a lot more visible when you add contrast in post-production. A photo that looks fine before editing can look awful once you’ve given it more life. That's just another example of when noise reduction software comes in handy.

Just some thoughts to keep in mind. Happy shooting!