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Digital Photography Apeture Question?

Digital Cameras Discussion

Digital Photography Apeture Question?

Postby Hosea » Tue Oct 10, 2017 8:44 pm

The Aperture controls the amount of light that passes through the lens and the amount or brightness of light that falls on the film or digital sensor.

The aperture can be thought of as the iris of an eyeball. It can be enlarged to allow more light to pass through a lens, or constricted to decrease the amount of light passing through it.

?Opening? the aperture allows more light to pass through the lens, ?closing? the aperture reduces the amount of light that passes through the lens.

The size of an aperture is denoted by an F-Number.

The smaller the F-number, the larger the aperture. The larger the F-Number, the smaller the aperture.

Larger Aperture______________Smaller Aperture

F/1.4 F/2 F/2.8 F/4 F/5.6 F/8 F/11 F/16 F22

F-Numbers are written as F/X because the F-Number is determined by the Focal length divided by the diameter of the aperture.

This is why any aperture lets in the same amount of light on every lens.

In photography the exposure is a combination of an aperture and shutter speed.

When you make changes in luminosity or exposure levels, the changes are referred to as ?Stops?.

When changes to an exposure are made using the aperture specifically, this is referred to as an F-Stop.

Stops are commonly measured in either in halves or doubles but are commonly set to 1/3 stop increments in various cameras.

One stop more of exposure is twice as much light.

One stop less of exposure is half of the light.

You can either adjust the aperture or the shutter speed to half or double the light falling on the film or digital sensor.

Bokeh is not how far something is out-of-focus, bokeh is the character of whatever blur is there.

Good bokeh causes the edges of blurred points of light to become undefined and soft, rather than sharp and clear.

A rounder opening produces softer and more natural out-of-focus areas.

Aperture not only controls the brightness or amount of light that falls on the film or digital sensor, the aperture also controls what is known as the ?Depth of Field?.

The depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.

A shallow depth of field may only have one clothespin on a line in focus / acceptably sharp while the rest are blurred out.

Only ONE plane of light is TRULY focused sharply.

If you have a large / wide / deep depth of field, that is still true.

Only one plane is truly focused and more sharp than everywhere else but other areas are just ?acceptably sharp.?

As the aperture is made smaller or larger, the depth of field becomes more shallow or larger/deeper/longer etc.


Large Aperture___________________Small... Aperture

Shallower/Smaller DOF_____________Deeper/Longer DOF

F/1.4 F/2 F/2.8 F/4 F/5.6 F/8 F/11 F/16 F22

Making photographs at smaller apertures creates a larger depth of field. Does this mean small apertures are better or sharper? No.

When making photographs using the smallest apertures, you may have noticed the photographs are not as sharp. The reason is diffraction.

Not enough room to explain that.

Commonly, lenses lose sharpness qualities due to diffraction when stopped down lower than F/8 on cropped sensor cameras.

All lenses have a sweet spot where they produce the sharpest image with a given camera sensor at a specific focal length either in the center or both the center and edges.

In practice, adjusting the aperture one stop above or below the sweet spot will not greatly affect image quality on a noticeable scale.

However, the farther you go in either direction the more noticeable it can be.

Diffraction impacts image quality the most with the smallest apertures, lens defects are the worst at the largest apertures.

So there you go, that's mostly everything the Aperture does. Not enough room to explain the rest of what it does.
Hosea
 
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Joined: Fri Jan 10, 2014 9:18 pm

Digital Photography Apeture Question?

Postby Dwayne » Wed Oct 11, 2017 4:51 am

In digital or analogue represent the same

A scale of relative measure of aperture size to make possible equal functioning of the standard photography procedure for every lens; aperture number= focal length/ aperture diameter
Dwayne
 
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Digital Photography Apeture Question?

Postby Byrley » Fri Oct 13, 2017 4:53 pm

Simply put, aperture is a hole within a lens, through which light travels into the camera body. It is easier to understand the concept if you just think about our eyes. Every camera that we know of today is designed like human eyes. The cornea in our eyes is like the front element of a lens ? it gathers all external light, then bends it and passes it to the iris. Depending on the amount of light, the iris can either expand or shrink, controlling the size of the pupil, which is a hole that lets the light pass further into the eye. The pupil is essentially what we refer to as aperture in photography. The amount of light that enters the retina (which works just like the camera sensor), is limited to the size of the pupil ? the larger the pupil, the more light enters the retina.

So, the easiest way to remember aperture, is by associating it with your pupil. Large pupil size equals large aperture, while small pupil size equals small aperture.
Byrley
 
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Digital Photography Apeture Question?

Postby Bela » Sat Oct 14, 2017 3:04 pm

The 'F' refers to the aperture of your digital camera.
An f1.8 lens can let in a lot of light, so it is good in low light conditions.
Aperture also is one of the factors that after depth of field (the wider the aperture (ie: f5.6 to f1.8) the shallower the depth of field).

Hope you enjoy your camera and have fun :)
Bela
 
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Digital Photography Apeture Question?

Postby Freemon » Sun Oct 15, 2017 12:52 pm

The bigger the f-number the smaller the aperture, thus less light goes through the lens and you have to compensate with a longer shutter speed.
Bigger f-numbers (small aperture) give great depth of field - focus sharp from front to back. Small f-numbers (big aperture) give small depth of field, good for getting blurred background in a portrait.
For portraits always use a moderately long focal length, such as 50mm or 70mm; do not use wide-angle (e.g. 18mm, 24mm) for portraits.
Freemon
 
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