One question I get asked many times is how do you get one thing, ie; the subject in focus and the background out of focus I will try and explain it simply.
There are three things that work together when taking photos that's good to know a bit about. Some call it a Exposure triangle of settings as changing one affects the others that is Shutter Speed which simply put is how quick the camera opens the lens for the photo and I touched upon this in my first blog post.
Another leg of the triangle is ISO, which in very simple terms is how sensitive your sensor is set to be. The Lower the ISO the more light is needed. A higher ISO works with less light but can introduce noise into the image.
And the Last peg of the triangle, which I will try to expand a little further on in this post, is Aperture. OK, what is Aperture? Very simply, it is how far the lens is opened when taking a photo and is measured in a term call F Stop. A low number Aperture ( also called F-stop) such as F1.4 opens the lens pretty wide and lets a lot of light in. Where as a high number Aperture/Fstop setting of say F22, only opens the lens a little bit so less light gets in.
What can this mean when taking photos? Aperture can be seen to have a big impact on what we call depth of field, which means how much is in focus a small Fstop number will give a shorter depth of field. So if you want to get something in focus and the background blurry you use as Low a F stop setting as you can for the camera and lenses your using. Here are some examples using a low Fstop to get the subject in focus and the background blurry.
Now I would be remiss if I didn’t mention the Exposure triangle again and highlight if you change one setting to get a certain effect you may well need to also adjust one or two of the there legs of the triangle. If you want to use a lower aperture setting to get a shallow depth of field you may well need to adjust the shutter speed or ISO to get the desired image you want. And do remember, if you increase the ISO you may well get more noise on your image. What ISO can you go up to? That will depend a lot on your camera play around and see what is the limit that works for you. The same goes with shutter speed, if you adjust that to low, you may have issues with blurry images for handheld shots. Again, depending on the camera and how steady your hands, trial and error, it will give you an idea of the lowest shutter speed you can use with your camera and still get clear images.
Above were some example photos where I used a lower Fstop number to limit the depth of field to primarily on the subject, ie; the flowers and my little toy sheep Bahbahra.
The next photo, which the main subject is the blossoms, i used a higher Fstop number as I wanted the background although not as clearly in focus but easy to see where it was taken.
And I come to the end of this post. I hope it made sense and was helpful.
Feel free to contact me if you have any questions.
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