During week one we not only learned about workflow, but we also had an introduction to the basics of both photography and image processing. During this introduction we learned about the exposure triangle the importance of the histogram and how to use it, and the importance of shooting in RAW and why we should only downgrade to JPEG for the use of file transmission and E-Mail.
The exposure triangle:
The exposure triangle is made up of the following three elements, shutter speed, aperture and ISO. In order to get a correct exposure it’s important that we balance these three elements, we can however push certain elements in the triangle to gain certain creative effects, but we need to understand that for every element we push there is a counter reaction. For example if i want to shoot an image with a deep depth of field, I would select a small aperture for example F16. By choosing F16 however I’ve created a very dark space between the lens iris and the sensor/film. To counter this I either need to use a longer shutter speed and perhaps a tripod or boost my ISO/change film, if handheld. The same applies for the shutter speed and ISO, by manipulating one element you must also change another in order to expose correct. They’re are other ways around this such as the use of filters and digital manipulation, however this is a very basic look into the exposure triangle and how it operates.
The histogram is a tool that shows us the levels of each colour present in our image, the histogram also works on a number scale, the scale on the histogram works between the numbers of 0 -255. Black or underexposed with no detail is found at the beginning of the scale at 0, burnt out white is found at the other end of the spectrum at 255. In theory any area displaying a number above 1 and below 254 on the histogram should have some amount of retrievable information to be found within it.
The best way to describe the histogram is that it looks like it has the appearance of a graph with a line through it. We can manipulate the ‘levels’ of each colour and the actual exposure of the image by physical grabbing this line and moving it. We can also manipulate the levels of an image by changing the values numerically, for example by changing blue from say 200, to 245 should give you a deeper shade of blue within the image.
This makes the histogram especially useful for making both experimentation and precision changes to both the colours in your image and the exposure of the image itself.
8 BIT or 16 BIT?
16 BITs is the colour channel that I have chosen to shoot my images at for this project, I have done this as a precautionary measure incase I should need to carry out any heavy manipulation of colour during the processing of the images. This also increases the quality of the recorded colours in the files, therefore making the files themselves of a much higher quality. If I’m shooting images for a book or a piece of work such as this, than the maximum quality available should be sought out. An 8 BIT channel, may be useful for when shooting jpeg images or sample images that are not expected to receive much scrutiny from the viewer.