Now let's discuss the Exposure Triangle.  The starting basics for good photography and arugably the most important thing to know about cameras and photography.  Understand the relationship between Shutter Speed, Aperture, and ISO is the most important thing you need to know as a photographer.  So lets talk about what each of them are and how they all work together to make an image.

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Shutter Speed

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First let's look at Shutter Speed.  The shutter of the camera controls how long the camera's sensor, or film, to light.  How long the sensor/film is exposed to light is the Shutter Speed.  Most DSLRs have a range from as fast as 1/8000s of a second to as slow as 30 seconds, and some have a mode called bulb where you can use a shutter release cable to manually keep the shutter open. 

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The longer the shutter is open the more light is reaching the sensor, making the photo brighter.  This also capture any movement in the subject of the photograph.  If you are taking a landscape photo of mountain which does not move, slower shutter speeds can be used.  However if you are shooting a sprinter running full speed to a finish line they will become blurry with a show shutter. Sometimes you want somethings to be blurry and show movement, sometimes you want everything frozen still in time.  Knowing when to shoot fast and when to shoot slower is key to capturing the movement, or lack or movement, you want.  In addition to movement the amount of available light will need to be considered when choosing your shutter speed.  If it's bright outside, high noon, no clouds, you may need a fast shutter 1/1000 or faster.  Are you in a dark room or maybe out at a night time shoot with a tripod? Then something slower will work much better.  

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Many things can add blur to a photograph, a fast moving subject, wind moving flowers or trees, vibrations, the shaking hands of the photographer.  I even have times where my camera is on a tripod but the vibrations coming from the traffic on the street still made my images blurry.

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When picking the perfect shutter speed remember to consider:

- the movement of the subject

- the available light

- the iso and aperture

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Aperture

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Now since we all understand shutter speed lets look at the aperture, the hole of the camera lens.  The size of the hole is measured in f stops shown on the camera as f/#.    The bigger the number the smaller the hole.  The smaller the number the bigger the hole.

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We use aperture to two main things, first we use the size of the aperture to control how much light gets to the sensor.  The larger the hole the more light comes through the lens and makes it to the sensore.  Too much light? Use a higher f stop (f/11, f/16).   Photos too dark? Open the aperture up and use a low f stop (f/1.4, f/2.8).

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Secondly we use the aperture to control Depth of Field.  Depth of field is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image.  Shallow/Narrow depth of field have a lot of out of focus parts. Think of a photo of a flower that is in focus but the trees and sky in the background blurry, While a Deep depth of field has most parts of the image in focus. 

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When picking the right aperture consider:

- Do you want a shallow or deep depth of field

- the available light

- the iso and shutter speed

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ISO

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In digital photography ISO refers to the sensitivity of the sensor.  The more sensitive the sensor the more light it pick up.  This is very useful when shooting in dark conditions.  However the more sensitive the sensor is the more "noise" or graininess you will see in your image. 

 

A typical ISO range is about 100-1600. I always try to shoot with as low ISO possible for the conditions at hand to have the clearest image. 

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When picking the right ISO consider:

- Try to get the lowest ISO possible for the light 

- the available light

- the iso and shutter speed

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USING SHUTTER SPEED, APERTURE, AND ISO TOGETHER

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Now how do where use these three together to make a good exposure?  First we need to look at the subject we are photographing. 

 

Are you shooting a landscape with no moving parts?  Then you may want to use a higher f stop (f/7, f/11, f/16) so all of the scene is in focus, and since the landscape is not moving around we can use a slower shutter speed.

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What if we want to shoot a portrait with a sharp in focus eye and blurry out of focus background?  Then we can shoot with the aperture wide open (f/2.8, f/4) to get that nice shallow depth of field.

 

If your shooting a sprinter at a sports event you will want to make sure you shutter speed is fast to stop his motion or you will end up with a blurry photo.

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Are you shooting something that needs to be a clear and tack sharp as possible then keeping your ISO at it lowest level is the way to go.

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Photography is very much a balancing act between these three parts.  Finding the perfect exposure may mean giving up some depth of field to get a correct exposure.  Working and this is what learning photography is all about. 

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This is where you as a photographer get to express themselves, show their creativity and create something unique. 

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