Aperture in the Exposure Triangle by 42nd St Photo

What is commonly known as the ‘Exposure Triangle’ in photography is more like a tripod with adjustable legs to allow the camera to take the best shot. Each leg of the tripod has to work with the others and photographers adjust the legs to to the specifications needed at the time. Today 42nd St Photo is taking a look at one of the legs of the tripod/triangle: Aperture.

When you look into your camera lens you see black blades of the shutter whorled into a point in the center of the lens. When the photo is taken, the blades open and form the aperture, the window that lets the light and image into the camera to be captured on film or memory card.

An analogy would be the human eye. Bright light causes the pupil to shrink and reduce the amount of light entering the eyeball while darkness causes the pupil to open wide to capture more light and see. The pupil is not the moving part of the eye: the iris or colored part of the eye is moving and changing the opening we look through to view the world around us.

In a camera, the size of the aperture is measured in f/stop numbers. Larger numbers mean that more of the shutter is blocking the light and the aperture is smaller. Smaller numbers conversley indicate that less shutter is being used so the aperture is larger.

Cameras carried by 42nd St Photo have a range of settings, from the automatic poin-and-shoot to the DSLR cameras that allow you to control things like f/stops. The advantage of being able to control the f/stop and hence the aperture is in the depth of field you want in your image.

Depth of field is essentially what is in focus in your shot. A smaller aperture (higher f/stop) means that more objects can be in focus even when in various distances from the camera lens, kind of like squinting to see clearer. Learning how to adjust the aperture in coordination with ISO and shutter speed will greatly enhance your ability to take the photographs you aim for.

Know your camera’s capabilities, and come to 42nd St Photo for all your photographic needs.


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