# Photography is the art of capturing light. Every choice that a photographer makes when taking a photo is based on this simple concept. What is photography?

## Presentation on theme: "Photography is the art of capturing light. Every choice that a photographer makes when taking a photo is based on this simple concept. What is photography?"— Presentation transcript:

Photography is the art of capturing light. Every choice that a photographer makes when taking a photo is based on this simple concept. What is photography?

How do digital cameras work? Digital cameras have an image sensor that is made of a special metal that reacts to light The image sensor is divided up into a grid containing millions of individual cells.

When light shines through the camera and hits the image sensor, each cell converts the light into a small amount of electricity (like solar power) The more light that hits a cell, the more electricity it creates The camera then reads the amount of electricity that each cell created and uses that information to create the image Each cell of the image sensor makes up one pixel of the final picture How do digital cameras work?

What about color? Each cell of the image sensor is coated with a filter that allows the camera to know what color hit it.

How do digital cameras work? What are megapixels? Megapixel is a measurement that tells a consumer how many cells a camera’s image sensor is divided into A five megapixel camera’s image sensor is divided into a grid of five million cells The more megapixels a camera has, the better its pictures will look when they are enlarged

How do photographers adjust how much light hits the image sensor? Photographers have three main ways to adjust how much light hits their camera’s image sensor: Shutter Speed Aperture ISO

Shutter Speed The shutter of a camera is what blocks light from the camera’s image sensor The longer the shutter is open, the more light that hits the sensor Shutter speed is measured in fractions of a second (ex: 1/500)

Shutter Speed Faster shutter speeds are used to freeze fast moving objects in a picture 1/60 th of a second is more time than 1/500 th of a second, so a shutter speed of 1/60 is slower than a shutter speed of 1/500 Shutter speeds slower than 1/60 aren’t usually used without a tri-pod, because the shutter is open long enough to capture the natural shaking in your hands, causing a blurry picture

Shutter Speed This photographer used a very slow shutter speed to blur the tail lights of passing cars. A faster shutter speed would have simply shown the cars on the freeway.

Shutter Speed This photographer used a fast shutter speed to capture a water balloon as it was popping.

Shutter Speed This photographer should have used a faster shutter speed to freeze the persons movements.

Aperture The second tool that the photographer can use to limit the amount of light that hits the image sensor is the aperture. The aperture works like the iris in your eye. It opens more to let more light in, and less to let in less light. In most cameras the aperture is found in the camera’s lens.

Aperture Aperture size is measured in “f-stops” The larger the f-stop number, the smaller the aperture opening (it’s opposite of what you would expect) The chart to the right shows some common f-stops

Aperture Aperture effects how much light hits the sensor, but it also determines depth of field Depth of field is how much of your image will be in focus A larger aperture setting like f/4 will blur out the background of an image A smaller aperture setting like f/16 will keep the foreground and background in focus

Aperture This photographer used a large aperture setting to blur the background of the photo

Aperture This photographer used a small aperture to keep everything in the picture in focus.

ISO As you learned earlier, your image sensor converts light into electrical signals These electrical signals are very small, and must be amplified before the camera can use them to construct the picture Your ISO setting determines how much the signals are amplified

ISO In general, the higher your ISO setting, the brighter your picture will be This can be handy when taking pictures in low light situations If you turn the ISO up too high, you do run the risk of having your pictures turn out a little grainy

Exposure Balancing shutter speed, aperture, and ISO is known as controlling “exposure” An over exposed photo is too bright and an underexposed photo is too dark Under exposedOver exposed

Auto Mode Most digital cameras have an Auto Mode that measures how bright it is and sets the shutter speed, aperture, and ISO for you automatically Auto Mode is normally fine for typical picture taking scenarios, but if you want to make your photo more artsy, you may want to change some of the settings to fit your needs All cameras are different, but there is normally a “P” mode that allows you to take control over the camera’s settings

Helpful Tips When shooting a picture, keeping your subject away from the center can make the photo more interesting.

Helpful Tips When shooting a picture, don’t shoot towards the sun if it can be helped. The sun is so bright it can overexpose portions of your picture.

Helpful Tips Camera shake is one of the most common causes of blurry pictures. As often as possible, try pulling your elbows in towards your body and exhaling completely before taking your photo.

Helpful Tips Although slow shutter speeds can cause blurry pictures, if used in an artistic way (usually with a tripod) blurry pictures can be very interesting.