Shaw Academy. Lesson 2 Course Notes. Diploma in Smartphone Photography

Transcription

1 Shaw Academy Lesson 2 Course Notes Diploma in Smartphone Photography

2 Angle of View Seeing the World through your Smartphone To understand how lenses differ from each other we first need to look at what's called the Angle of View of human Vision. This is essentially the view we see when we look straight ahead and how wide that view is. For most humans when we look forward without moving our head we can see an angle of view that is about 130 degrees wide. So basically if you stand still don t move your head or eyes and just look forward, you view of the world is about 130 degrees wide. However in reality the area of our vision that is in focus is only about 50degrees wide. This illustration shows the width of our angle of view that is actually sharp and in focus (indicated in pink) when we look straight ahead. As you can see it s a very small portion of our total vision (indicated in blue). How does this relate to smartphones? Smartphones can capture images much wider than what our focused vision can see. So keeping in mind that our eyes can only see about 50 degrees wide compare to our total angle of vision of 130 degrees. Smartphones typically can have an angle of view up to about 83degrees wide which is substantially wider than our own 50 degrees of focused vision. Therefore your smartphone has the potential to capture more of a scene in focus than our eyes will see as focused. However it is still narrower than our total angle of view. Lens attachments: Lens attachemnets can offer us an alternative view of the world, either narrowing the field of view of your camera or widening it. Typical lens options available to smartphone users are: Wide Angle Lens A lens with field of view wider than the angle of focused human vision. Telephoto x2 Lens These can bring your phones view to 2 times closer to your subject. Fish Eye Lens They give us an extremely wide view of the world. In order to achieve this wide view the images are very heavily distorted which is very prominent around the edges. Curved lines are a typical distortion with these lenses.

3 Macro Lens A lens that allows you to get extremely close to your subject while still maintaining its ability to focus on it. This allows us to capture incredible detail from our subjects. A brief history of photography* *The word "photography" from the Greek word phōtos meaning "light and graphé meaning drawing" together mean "drawing or painting with light". The concept of photography has been around for about 2500 years all the way back in 400BC when a Chinese philosopher called MO-ti mentioned the basic concept of light forming images. They realised that when sitting in a darkroom, light entering the room through tiny pinholes formed a picture on the wall on the opposite side of the room. Over the next 1000 years this lead to development of that camera obscura. The camera obscura is a darkened room with a pinhole in one wall. Because of the physics of light, light passing through the tiny hole, projects the scene from outside on the opposite wall of the room. Because of the physics of how light moves, the picture would be upside down and back to front. At this stage there was still no way to record the image. A painter or artist would sit in the room and sketch or paint over the image that was been projected. Over the next years the desire to permanently record this image by some other means became a desire of many scientists and inventors. Eventually in 1827, French inventor Joseph Nicephore Niepce captured an image on a bitumen-coated metal plate using a camera obscura to produce the first photographic image he called heliographs. However the quality was not very good or detailed. In 1838 Louis Daguerre who previously worked with Niecpes revealed his own superior process to the world. His recorded images were much higher quality and photography was officially born. In the meantime, competition and consumerism drove the development of the camera obscura to become smaller, more portable and ultimately developed into the cameras we are familiar with today. The technology behind capturing images developed also to accommodate these new cameras. Daguerre s light sensitive metal plate, became 35mm film, which has now practically been replaced by light sensitive sensors inside our digital cameras and smartphones.

4 Exposure The Camera Exposure works the same way in our modern cameras. The digital sensor, which captures and records our images is light sensitive. Light entering the camera forms an image on the sensor, if we do not control the light entering the cameras our images will either become too bright or too dark. Too much light hitting the sensor and the image becomes over exposed. Not enough light and the image will be under exposed. What we want to achieve is the right level of brightness to replicate the scene as we saw it. We refer to this as correct exposure.

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