Following on from my previous posts about buying a camera and getting started, I have been asked to attempt to explain the different aspects but in English and not camera speak. So Todays topic is Aperture... the dreaded F-stop, which works upside-down and back-to-front yet is a vital part of taking control of the images you produce.
Most cameras bought by beginners start off being used in Auto mode, or if the photographer is feeling adventurous... Aperture Priority mode.
Aperture priority is a camera mode that lets the photographer set the aperture while the camera chooses the shutter speed and the ISO. This mode is a semi-automatic tool that can help photographers learn how aperture interacts with other camera settings.
How it works
The photographer chooses an aperture value
The camera's light meter measures the lighting conditions
The camera calculates the correct shutter speed to match the aperture and ensure proper exposure
The above images show the difference in light gathering between wide open aperture and narrowed aperture at the same shutter speed. I used a 30mm lens and only opened it to f3.5 to replicate the values of a normal kit lens which is usually a f3.5 or f4 and i left the iso setting in auto to assist with the light, open shot at ISO1000 and narrow required ISO6400, which we are not worried about yet. the next 2 images show the depth of field or focus range difference between the two ends of the aperture scale.
This is f16
And this is f3.5, notice how much less of the frame is in focus? This is due to a load of technical gibberish that we don`t really need to know at this moment, but what we do need to know is that the f-stops run backwards to what our brain tells us, which is surely the higher the f number, the more light is let in, well no... the lens has blades which control the aperture, these close from the outside to the centre, so f3.5 is the blades at the outside of the lens and as you increase the number, you increase the amount of blade blocking light, hence the upside-down numbers... think of it as curtain measurements, on an 18ft window, a 3.5ft curtain will allow lots of light to pass through, and a 16ft curtain will stop more light.
And to explain the focus or DoF (Depth of Field) we will just say Black Magic happens, but is has to do with science and confusing things which doesn`t help us get our head round what aperture does. Not as beginners anyway, all we really want to know is what the various terms mean, and what they do, in the simplest form possible.
So to recap, smaller the F number, the more light and less DoF we get, and the Higher the F number, the less light we get but more DoF.
Play around with your cameras, use a tripod or a firm base, and shoot your chosen target at varying apertures, your own camera will have its own characteristics that you can use for artistic effect or work around by varying your aperture. Go have fun, instead of taking photography too seriously as a beginner, have fun experimenting, not only will you enjoy it more but you will also teach yourself so much. At the end of the day, the why`s and wherefore`s and how`s are only important if you are doing a photography course and need to sit an exam. Yes there is a lot more to aperture, but you will learn them as you progress, this is just your appetizer if you like, just enough info to make it less scary and to allow you to research deeper if that is how you wish to progress.
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