I am completely lost when it comes to using a big fancy camera, believe me, I film everything on my shitty iPhone camera and so knowing I had to use such an expensive fiddly bit of equipment it made me somewhat regret my entire decision. No I’m only joking, I was actually really excited to learn how to make really cool videos and so I dove straight into researching basic functions and settings!
GETTING THE EXPOSURE RIGHT.
What controls exposure?
There are three things which control exposure:
1. The aperture
2. The shutter speed
3. The setting of the ISO
1) THE APERTURE
Inside the lens, is a mechanism that opens to allow light to pass through the lens into the camera (and onto the sensor). The amount or size of the opening varies and is referred to as an ‘f’ number, for example f2, f2.8, f4 etc.
The range of apertures is shown below:
f1.4, f2, f2.8, f4, f5.6 f8, f11, f16, f22, f32
The other important thing to understand about f numbers is that each step in the f number scale, lets half as much light in. So for example, f2 lets in twice as much light in, as f2.8. Similarly, f22 allows only half as much light in, as f16.
The aperture opening also determines the ‘depth of field’ in a photograph.
When you focus on a subject, a certain distance, both in front of the subject and behind the subject is also in focus. This area is called the depth of field. So, by controlling the aperture, you can determine how much of the picture is in focus and use it to be creative.
For example, if you were taking a picture of a landscape, you would want the depth of field to be as big as possible, so from close foreground to distant background is in focus. On the other hand, if you were taking a portrait of someone in a crowd, you might want to have a very shallow depth of filed so your subject is isolated from everyone else around them.
Small f number = big opening = shallow depth of field = less of the picture in focus
Large f number = small opening = greater depth of field = more of the picture in focus
2) THE SHUTTER SPEED
Inside the camera is a shutter, which is a bit like a curtain and opens, usually for a split second and then closes. The sensor in the camera is exposed to the scene it sees through the lens and the detail is captured and saved as a picture on the card in the camera.
The time the shutter is open is called the shutter speed and is normally stated in fractions of a second:
1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000 1/2000 1/4000
3) THE ISO SETTING
The final factor that controls exposure is the ISO setting. The first thing to say is that you don’t need understand what the acronym ISO stands for.
In the ‘old days’ before digital cameras, a roll of film was loaded to the camera. The rolls of film could be bought in various ISO speeds. The range was normally 50 ISO, 100 ISO, 200 ISO and 400 ISO. Having loaded the film, every picture on the roll had to be taken at the same ISO speed.
These days, with digital cameras, the ISO range is vast and typically:
100, 200, 400, 800, 1600, 3200, 6400.
On high end digital cameras, the range extends to:
12800, 25600, 51200, 102400.
Good lighting conditions = Low ISO speeds = 100 ISO or 200 ISO
Overcast or cloudy conditions = Medium ISO speeds = 400 ISO or 800 ISO
Poor light or floodlight conditions = Fast ISO speeds = 1600 ISO to 6400 ISO