Introduction to Aperture



Aperture is an important aspect of a camera’s ability to increase or reduce light exposure, allowing the camera to capture all kinds of situations in very bright light or rather dimly lit settings. It is perhaps most often confused with shutter speed, though the two actually work in tandem to produce photos that can freeze motion, create artistic blurs, or capture the night sky without so much as a single misplaced pixel. For digital camera owners just getting started with aperture, there are a few things to know.

What is Aperture, Exactly?

The best way to think of a camera’s aperture is to consider the iris of the human eye. Aperture is solely responsible for allowing light into the camera lens, while shutter speed is responsible for controlling how long that light is allowed to stick around before it’s shut out and the photo is produced.

Aperture essentially controls how widely the camera’s lens open, and this controls how much light is made available to the lens for the purpose of processing a photo and capturing the scene. A larger aperture setting means that the lens opens wider and lets more light in. This is ideal for a situation that involves very low light. A smaller setting, then, indicates just the opposite: The camera’s lens opens only a very small amount, letting a minimal amount of light in. This setting would be ideal for snow scenes, beach pictures, or other very bright backdrops.

Another great result of aperture control is that photographers can determine their photo’s depth of field. Because aperture can alter the focus of the picture, they can either give the photo unlimited depth or bring the focus only to a certain subject or area of the picture. It’s one o the best ways to produce concentrated subject focus, artistic pictures, and tightly controlled landscapes.

Measuring Aperture: How it Works and What it Means

Aperture is measured in units known to photographers as “f-stops.” The simple definition for an f-stop is this: The “F” refers to the focal length of the camera’s lens, while the “stop” refers to the number of stops used to widen or narrow the aperture opening. When an f-stop is measured it typically looks something like f/1.0, f/3.0 or similar. In some cases, the f may be on top of the number so that it resembles a traditional fraction.

The more important thing to know about aperture measurements is how they relate to the camera’s aperture itself. Simply put, a smaller f-stop measurement indicates that the aperture opening is smaller. Larger f-stop measurements mean that it is open a greater amount, letting in more light and contributing to a different type of focus than a smaller measurement would allow. Greater aperture means bigger f-stop numbers, and the reverse is true. It’s actually pretty simple to get used to.

Aperture and Focus: Beyond the Impact of Lens Exposure

Though aperture is commonly considered a lens exposure setting, it’s also heavily involved with the focus of a photograph. It’s already been covered that higher aperture numbers equate to a greater amount of light getting into the photo. Higher numbers also permit the photo to display a much larger depth of field. The larger the number, the greater the focus, and that means finer details even far in the background can be seen by the naked eye when the photo is displayed or printed.

The opposite is, of course, also true in this case. A smaller aperture number would focus centrally on the subject at hand, but it would blur the background and significantly reduce the photo’s depth of field. A smaller aperture number is a perfect way to bring a subject, like a person or even a rock formation, into focus while completely blurring the background. At very low aperture settings, this can even appear quite artistic when the photo is printed or displayed on a digital device.

Digital SLR vs. Point-and-Shoot: How Aperture Differs Between Camera Types

As always, today’s digital SLR cameras allow for more control over aperture and many other settings than their point-and-shoot counterparts typically permit. Digital SLR cameras often come with an f-stop knob that can be used on the fly to create stunning photographs with any depth of field or exposure required by the photographer. These cameras often come with on-screen controls relating to automatic aperture, a so-called “manual mode,” and “Aperture Priority” mode, which allows the camera to focus first on aperture and second on any other exposure settings.

Point-and-shoot models typically allow for only very limited aperture control, if any. Typically, aperture is automatically adjusted by the camera with built-in light sensors and focal tools. The most common result of this is the moving “box” that follows a subject and blurs the background. Essentially, this box is a way for the camera to use very low aperture without any manual adjustment.

A Great Way to Improve the Quality and Depth of Photography

The two things most closely associated with a camera’s aperture setting are light and focal depth. By adjusting the aperture between higher and lower ratings, photographers can either bring their subject into focus, extend their depth of field, or use exposure to increase the quality and visibility of key elements in the final picture.

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