Photography: Why Your Photos Are Grainy

Newcomers to 35mm (SLR and Digital SLR) photography commonly ask why their photos appear to be more grainy than the sleek, crystal clear shots of professionals.

The answer lies within the setting of your ISO speed. Traditionally, ISO refers to film speed. As confusing as it seems, ISO actually stands for International Organization for Standardization. However, according to Thinkcp.com, ISO is not an exact acronym. Thinkcp.com continues to explain, "In fact,"ISO" is a word,derived from the Greek isos, meaning "equal", which is the root of the prefix "iso-" that occurs in a host of terms, such as "isometric" (of equal measure or dimensions) and "isonomy" (equality of laws,or of people before the law) ... From "equal" to "standard", the line of thinking that led to the choice of "ISO" as the name of the organization is easy to follow."

Now, as I said before, in a traditional sense, ISO refers to film speed - But what about Digital SLR? It most certainly is known for not using film of any kind, so how does a Digital SLR use ISO if there is no film? The creators of this technology have passed down this concept on a digital level. In essence, you are not controlling the film speed but the light sensitivity of the digital censor - "Virtual film", if you will. So, from an external point of view, this concept seems to work exactly the same in both forms of photography - Film and digital.

ISO speed is based on a number system typically beginning with 100 and ending with 1600. On the ISO scale, 100 is less sensitive to light, where as 1600 is enhanced to be more sensitive to light - Thus, creating visual distortion in the form of grain. When determining your ISO speed, you must understand that using a lower ISO number will result in improved quality but, as mentioned before, it also lowers the overall amount of light that the camera's sensor records. This means the lower ISO number you choose, you will have to use slower shutter speeds, and/or larger aperture to make up for the loss of light the ISO speed caused and vice versa for higher iso numbers closer to 1600.

Be sure not to confuse grain with noise. This happens more often in video production, but sometimes colors like green are known for causing visual noise when editing in post production due to chroma factors and color sampling levels (compression), which is an entirely different article. All in all, if you have the option to shoot with a lower ISO speed, by all means, do so. Just remember that if you're in low light situations, like an indoor party at night time, it may not be a good idea due to the fact that you'd have to decrease the shutter speed (if your aperture cannot makeup for all of the loss of light), which can result in an unwanted blurry picture!