A look into how a camera aperture scale determines the amount of light required for excellent photographs with the proper settings.
Define Aperture Photography
The aperture is one of two principal components for controlling the light into the camera; the second is explained in my previous post “Camera Shutter Speed Explained”.
In this post, we are going to learn about the camera aperture chart and what exactly does it mean for starters. So when we talk about the f-stops, this refers to tell us the size of the aperture or how big the opening is inside the lens barrel to allow light to pass through to the sensor in the camera that records your picture. The smaller the number is for your f-stop, the bigger the opening is for the passage of light. The opposite is true as you increase the size of your f-stop you reduce the aperture size.
You see the iris is the mechanism that is used to control and create the aperture for the different sizes for the amount of light available to come into the camera. Each f-stop will double the incoming light between each setting or half the amount of light entering the camera determined by whether your dialling up or down for the aperture sizes.
To figure out your f-stop, you can get your f-number by taking the focal length of your lens and divided it by the diameter of the opening of the lens. That is the equation that will give you the f-number.
So your fist part is the focal range of the lens or how much zoom that your lens has.
The second part is how much diameter of opening you have in the lens.
If we use a prime lens of 50 mm with an opening diameter of 12.5mm across
Aperture (f) = Focal Length / Aperture Diameter
f = 50 mm / 12.5 mm
f = 4 notated as f/4
Now if we take this same prime lens with a diameter of 25mm and put that into the equation, you divide 50 by 25 giving you an f-stop of 2, so you end up with f/2.
Below is a photo showing a camera aperture chart displaying full f-stops in your possible camera aperture range. The reason I say the possible range is not all lenses are capable of using all f stops do to size and length of barrel that make up the lens. That will be something I will discuss in another post.
In the different cameras, you have a mode dial where you can choose A or Av depending on which camera you use to put your setting in picture priority mode. Once you have selected this setting in your display, it will show what your f-number is set on in your camera.
For the Canon camera, the jog dial is usually up on front above the shutter button while the Nikon has it located where your thumb rests when you hold the camera.
So if we were to take a canon camera and spin the dial all the way to the left, this would give us the biggest aperture setting for opening up for maximum light that you can have. Just as you spin the dial all the way to the right, you get the smallest setting in the aperture for how much you would minimize the amount of light you would let in.
Some would say why control the aperture?
What it comes down to is you can have blurry pictures because subject or camera has moved before the sensor could finish recording the image you were trying to take. You see the aperture and shutter speed work together by opening the aperture to let in more light we can let the shutter close faster requiring less time for the camera or the subject to sit still for clearer photos.
The first line of defence against blurry photos is by having a bigger aperture. By doing this, it works very efficiently when taking photographs of people and other subject matters for portrait shots. There are other times when you do want lower aperture settings for such pictures as landscapes etc. and here’s why.
Choose a large aperture when you want to blur in front and behind your subject in portraits by using an aperture setting of f/2.8 for instance. Now in the case you want an excellent and clear imagery for the entire photograph such as a landscape, then you would want to use a smaller aperture setting such as f/16 that gives your photos a much sharper image with no blurring. These two F stops are kind of in the middle from the chart above for each type of shot taken in the photographs below giving you the best camera aperture starting point.
So from the information above you can define aperture photography and how it applies to taking excellent photographs by understanding the difference between the amount of light required for some of your different kinds of photos. In other related posts, we will go over in more depth on how this all ties in together with your Shutter Speed and ISO settings.
” Hi once again, I’m Travis Smithers author of Say It With Photographs where you will find tutorials on photography, editing software, cameras and accessories. The use of post production equipment and their operation to the creation of fantastic gifts for you, friends and family, enjoy. Comments and questions always welcomed here!”