Pillars of photography Or The Exposure Triangle

The Power Players Aperture Shutter Speed ISO Size of the hole that lets light into the camera Shutter Speed How long the light is allowed to enter the camera ISO How sensitive the media recording the image is to light

Aperture The “hole” story

Aperture The aperture is the hole that allows light to travel through the lens of the camera. Likely one of the most quoted, and least understood photographic term. “What was your aperture setting?” F 16 ”Looks really good” Generally speaking, people ask about aperture settings, however they don’t ask about the ISO setting or shutter speed.

Aperture A normal issue people have when discussing aperture is that a large number results in a small hole….how? The aperture value, often referred to as an F-Stop comes from a mathematical equation. Focal Length of lens / Physical size of opening 100 mm lens/ 25mm opening= F4 100 mm Lens/ 10mm opening= F10 You will get a bigger number with a smaller hole and a smaller number with a bigger hole due to the math of division.

Aperture Another thing that messes people up is how is F5.6 to F6.3 twice the light? Again, this is a math thing….derived by focal length of lens, physical size of the opening and the good old (pi)r2 A larger aperture allows more light to enter the camera in less time, this normally equates to a faster shutter speed. Conversely, a smaller aperture will normally make for a slower shutter speed. One of the biggest things you need to know about aperture to get started in photography is this: It controls depth of field

Depth of field How much of your image do you want in focus? Just the persons face, I want the background blurry Small F-Number, (i.e.: F5.6), this will keep the subject sharp while blurring the background. Everything…I want it all F16 to F22 are good numbers for keeping the entire image in focus. For example…

Shallow DOF Settings for this shot were: ISO: 100 Aperture: F6.3 Shutter Speed: 1/320th of a sec Focal Length: 163mm

Deep DOF Settings for this shot were: ISO: 100 Aperture: F22 Shutter Speed: 1/13th of a sec Focal Length: 28mm

What is Depth of Field? Depth of Field is a term put to the amount of image that is in acceptable focus. There is lots of tecnobabble on this subject, however suffice to say that the following rule of thumb applies to your focal point: Two thirds behind One third in front

Based on an aperture of F4 Tecnobabble Focal Length (mm) Focal Distance Depth of Field 10 0.5 (1.64 ft) 0.482 (1.581 ft) 20 1.0 (3.281 ft) 0.421 (1.381 ft) 50 2.5 (8.202 ft) 0.406 (1.332 ft) 100 5.0 (16.4 ft) 0.404 (1.325 ft) 200 10 (32.8 ft) 400 20 (65.62 ft) Based on an aperture of F4

Smaller apertures normally require a tripod Small Aperture Aperture value F22 This small aperture opening forces the shutter to stay open for a longer period of time, this allows you to make water seem silky. Smaller apertures normally require a tripod Almost everything in the image is in the same focus as a small aperture allows for greater depth of field.

Large apertures can be used easily for hand held shots Aperture Value F5.6 The large aperture opening allows a great deal of light into the camera in a very short period of time, as such, the shutter speed will be increased significantly. Backgrounds are normally blurred with large apertures as the shutter isn’t open long enough to capture all of the reflected light and detail Large apertures can be used easily for hand held shots

Mid-range Aperture Aperture value F8 Mid-range apertures will allow you to have greater depth of field while still blurring some of the background. This can be useful when you are trying to capture larger groups of people, or there are subjects of interest in the general proximity of your main subject.

Darker lighting and dark clouds set the mood. Aperture F13 I chose F13 for the relatively deep depth of field, however I didn’t want the shutter open so long as to make the waves in the background blur. Good texture in the foreground and lighthouse in acceptable focus in the background gives the person viewing the image a sense of the location and time of year. Darker lighting and dark clouds set the mood.

Aperture F5.6 Applied a shallow depth of field on this shot to isolate my primary subject. I wanted to show the male to be ever vigilant while the female was feeding. Female and background are blurred, foreground is limited in focus. Male in sharp focus with light reflection in his eye.

Aperture Questions?