I Can’t Sleep - Aperture | Gentle Bedtime Reading for Sleep

Episode Date: April 3, 2019

Ease into rest with calm bedtime reading about aperture to help insomnia and sleepless nights fade away. This soothing episode explores the concept of aperture, from its role in controlling light in cameras and photography to its meaning in optics and vision. Benjamin’s gentle cadence turns technical details into a peaceful journey of discovery. With no whispering or hypnosis—just calm, fact-filled storytelling—you’ll find your mind settling, stress easing, and rest arriving naturally. Press play, imagine light passing through a lens, and drift into sleep. Want More? Request a Topic: https://www.icantsleeppodcast.com/request-a-topic Ad-Free Episodes: https://icantsleep.supportingcast.fm/ Shop Sleep-Friendly Products: https://www.icantsleeppodcast.com/sponsors Join the Discussion on Discord: https://discord.gg/myhGhVUhn7 This content is derived from the Wikipedia article on Aperture, available under the Creative Commons Attribution-ShareAlike (CC BY-SA) license. Read the full article: Wikipedia – Aperture. Happy sleeping! Learn more about your ad choices. Visit megaphone.fm/adchoices

You're listening to a Glassbox media podcast. What if I told you that most of the modern day self-help advice you've been hearing could actually make you worse? The key to a better life isn't about feel-good gimmicks that sound catchy. The Mentally Stronger Podcast gives you access to a licensed therapist who shares science-backed tools that will actually change your life. Hi, I'm Amy Morin, psychotherapist, mental strength trainer, and international best-selling author. In each episode, we cover research-back strategies, like how to stop relying on willpower and start creating habits for lasting change. And the five mental strength-building exercises you can do from your couch. I also speak to world-class experts like Dr. Nicole Kane, who shares how to permanently heal anxiety by addressing the root cause.

With over 200 episodes in our catalog, this podcast is for you if you're ready to crush self-doubt, conquer challenges, and become stronger than ever with therapist-approved strategies that can change your life. Listen to Mentally Stronger with therapist Amy Morin, wherever you get your podcasts. Welcome to the I Can't Sleep podcast, where I read random articles to pour you to sleep with my soothing voice. I'm your host, Benjamin Boster. This episode is from an article on Wikipedia entitled, aperture. Enjoy the episode. Apperture. In optics, an aperture is a hole or an opening through which light travels.

More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that comes to, to a focus in the image plane. An optical system typically has many openings or structures that limit the ray bundles. Ray bundles are also known as pencils of light. These structures may be the edge of a lens or mirror, or a ring or other fixture. that holds an optical element in place, or may be a special element such as a diaphragm

placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that primarily, primarily determines the ray cone angle and brightness at the image point. In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop, rather than the physical stop or the opening itself.

For example, In a telescope, the aperture stop is typically the edges of the objective lens or mirror, or of the mount that holds it. One then speaks of a telescope as having, for example, a 100-centimeter aperture. Note that the aperture stop is not necessarily, the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a relatively large stop to be the aperture stop for the system.

In astrophotography, the aperture may be given as a linear measure, for example, in inches or millimeters. or as the dimensionless ratio between that measure and the focal length. In other photography, it is usually given as a ratio. Sometimes stops and diaphragms are called apertures, even when they are not the aperture stop of the system. The word aperture is also used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy, for example, a photometric aperture around a star usually corresponds to a circular window around the image of a star,

within which the light intensity is assumed. Application. The aperture stop is an important element in most optical designs. Its most obvious feature is that it limits the amount of light that can reach the image film plane. This can be either unavoidable, as in a telescope, where one wants to collect as much light as possible, or deliberate to prevent saturation of a detector or over-exposure of film.

In both cases, the size of the aperture stop is constrained by things other than the amount of light admitted. However, the size of the size of the, The stop is one factor that affects depth of field. Smaller stops, larger F numbers, produce a longer depth of field, allowing objects at a wide range of distances to all be in focus at the same time. The stop limits the effect of optical aberrations.

If the stop is too large, the image will be distorted. More sophisticated optical system designs can mitigate the effect of aberrations, allowing a larger stop and therefore greater light-collecting ability. The stop determines whether the image will be vignetted. Stops can cause the intensity reaching the film or detector to fall off toward the edges of the picture, especially when, for off-axis points, a different stop becomes the aperture stop by virtue of more light than did the stop that was the aperture stop on the optic axis. A larger aperture stop requires larger diameter optics, which are heavier and more expensive.

In addition to an aperture stop, a photographic lens may have one or more field stops, which limit the system's field of view. When the field of view is limited by a field stop in the lens rather than at the film or sensor, vignetting results. This is only a problem if the resulting field of view is less than was desired. The biological pupil of the eye is its aperture in optics nomenclature. The iris is the diaphragm that serves as the aperture stop. Refraction in the cornea causes the effective aperture, the entrance pupil in optics parlance.

Two differ slightly from the physical pupil diameter. The entrance pupil is typically about four millimeters in diameter, although it can range from two millimeters, F8.3, in a brightly lit place to 8mm F2.1 in the dark. In astronomy, the diameter of the aperture stop, called the aperture, is a critical parameter in the design of a telescope. Generally, one would want the aperture to be as large as possible to collect the maximum amount of a telescope. light from the distant objects being imaged. The size of the aperture is limited, however, in practice by considerations of cost and weight,

as well as prevention of aberrations, as mentioned above. Apertures are also used in laser energy control, close aperture Z-scan technique, diffractions patterns, beam cleaning. Laser applications include spatial filters, cue switching, high-intensity X-ray control. In light microscopy, the word aperture may be used with reference to either the condenser changes angle of light onto specimen field, field iris, changes area of illumination, or possibly objective lens forms primary image. See optical microscope. In photography, the aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter,

The aperture size will regulate the films or image sensors degree of exposure to light. Typically, a fast shutter will require a larger aperture to ensure sufficient light exposure, and a slow shutter will require a smaller aperture to avoid excessive exposure. A device called a diaphragm usually serves as the average aperture stop and controls the aperture. The diaphragm functions much like the iris of the eye. It controls the effective diameter of the lens opening. Reducing the aperture size increases the depth of field, which describes the extent to which subject matter line closer than or farther from the actual plane of focus appears to be in focus.

In general, the smaller the aperture, the larger the number, the greater the distance from the plane of focus the subject matter may be while still appearing in focus. The lens aperture is usually specified as an F number, the ratio of focal length to effective aperture diameter. A lens typically has a set of marked F-stops that the F-number can be set to. A lower F-number denotes a greater aperture opening, which allows more light to reach the film or image sensor. The photography term 1F-stop refers to a factor of the square root of 2, approximately 1.4. change in f number, which in turn corresponds to a factor of two change in light intensity. The photography term one F stop refers to a factor of the square root of 2, approximately 1.41, change in F number, which in turn corresponds to a factor of 2 change in light intensity.

Aperture priority is a semi-automatic shooting mode used in cameras. It permits the photographer to select an aperture setting and let the camera decide the shutter speed and sometimes also ISO sensitivity for the correct exposure. This is also referred to as aperture priority auto exposure, A-modeusory, A-mode, AV mode, Aperture value mode, or semi-auto mode. Typical ranges of apertures used in photography are about F-2.8 to F-22, or F-2 to F-16, covering six stops, which may be divided into wide, middle, and narrow of two stops each, roughly using round numbers, F2 to F4, F4 to F8 and F8 to F-16, or for a slower lens, F2.8 to F-F-1-F-1 to F-11, F-11 to F-11 to F-1, F-1 to F-1 to F-Even, F-1 to F-22. These are not sharp divisions and ranges for specific lenses vary. Maximum and

minimum apertures. Further information, lens speed. The specifications for a given lens typically include the maximum and minimum aperture sizes. For example, F1.4 to F-22. In this case, F-1.4 is the maximum aperture, the widest opening, and F-22 is the minimum aperture, the smallest opening. The maximum aperture opening tends to be of most interest and is always included when describing a lens. This value is also known, as the lens speed as it affects the exposure time. The aperture is proportional to the square root of the light admitted and thus inversely proportional to the square root of required exposure time such that an aperture of F2 allows for

exposure times one-quarter that of F-4. Lenses with apertures opening F2.8 or wider are referred to as fast lenses. Although the specific point has changed over time, for example, in the early 20th century, aperture openings wider than F6 were considered fast. The fastest lenses for the common 35 millimeter film format in general production have apertures of F1.2 or F1.4, with more at F1.8 and F2.0. And many at F2.8 or slower. F1.0 is unusual, though sees some use. When comparing fast lenses, the image format used must be considered. Lenses designed for a small format such as half frame or APS-C need to project a much smaller image circle than a lens used for large format photography.

Thus, the optical elements built into the lens can be far smaller and cheaper.