Since I have been a bad girl and have yet to give you all a January photography lesson, this week I will post two blogs. One will cover the basics of your camera’s light sensitivity and the other will cover the photography rule of leading lines.

Let’s Get Started

A camera’s ISO setting controls its sensitivity to environmental light. ISO stands for International Organization for Standardization and is the standard measurement used to rate a camera image sensor’s responsiveness to available light.

ISO is a measurement left over the Dark Ages of film cameras. Before the versatile beauty that is digital photography, photographers had to plan in advance what how much light sensitivity they needed their film to have during on a shoot. Film was rated at ISO 100 for use during blaringly bright sunny days while ISO 800 was needed during low-light shooting. Basically a higher ISO number meant the film had more sensitivity to light and therefore could create an image using less light. There were higher ISO ratings available for specialized night photography, but those were a bit too expensive to sell in mass markets (and way too rare for a teenager like me to play around with). Nowadays, my shiny mid-priced Canon digital SLR (currently on the market for about $700) comes ready to shoot an ISO range of 100-3200. The ISO is easily adjusted with a single camera button. I’ve seen high-end camera systems with maximum ranges closer to 12800. Most modern cameras also feature an auto ISO mode.

There are key advantages to knowing how to handle your ISO setting, the foremost of these being able to understand ISO’s relationship with a good quality photograph. If the ISO is too high on a bright day, the produced photographs will have a “blown out” appearance (i.e. lighter colors such as whites and creams will seem to glow). If the ISO is too low, you may not see anything all because the photograph will be blacked out. There is also the risk of an image appearing grainy or noisy if the ISO tries to compensate for too much low light. A grainy image will look like it has green or red squares and is considered poor photography. To combat these problems, know your ISO ranges and understand their strengths and weaknesses.

Let’s Break it Down

ISO 100 and lower – Exceptional quality for brightly lit places, such as in bright sunlight. The setting allows for lots of detail and excellent image quality.

ISO 200 – Should be generally be used on dull days with overcast or cloudy skies. The setting adds a small amount of noise. (200 or 400 ISO often work well for dawn and dusk shots.)

ISO 400 – Works fairly well for indoor photography so long as the room is well-lit or you are using a decent flash; however, noise can be seen in your images.

ISO 800 and up – This setting is only effective with high quality digital SLR (Single Lens Reflex) cameras. If you use a small point-and-shoot compact camera, this setting will make your images look extremely noisy.


Grab your camera and practice shooting in different light levels switching back and forth between the ISO levels so that you can see the way your camera interprets light. Email me with any questions.

I will talk about how to control noise in another article, and also about the relationship between ISO, aperture and shutter speed.

Until we meet again, I wish all of you brilliant flashes of perspective!

[ O*] Alycia