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May 13, 2013

What is Aperture?

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Written by: Lawrence
photographySILO free workshop on Aperture


A lens aperture can control the depth of field and allow capturing
images in low light conditions, but it’s also one of the most creative tools in
photography. Aperture can create beautiful backgrounds with light via bokeh and also create the sparkle from light sources.

This tutorial on Aperture is broken down in three parts.

PART I: Aperture
Definition. What is Aperture?

PART II: What is
F-stop aka Aperture Value and how it relates to photography.

PART III: Uses of
Aperture (Creative and Functional uses)


The Merriam Webster definition of aperture is as follows.

1. The opening in a photographic lens that admits
the light.

LEARNING TIP: Think of the Aperture
as your eyes pupil.  Example: Do
you recall being in the doctors office and having a
light pass left to right at your eye to check whether your pupils are dilating?
Well think of this like your camera. When there is a lot of light your pupils
get smaller to allow less light as not much light is necessary to see and when
there is not enough light the pupils get bigger. The Same principle applies when
trying to understand Aperture.

You might often hear another tip when understanding Aperture
and it is the inverse relationship between Aperture number aka f-stop to the
Aperture Opening. In part II, I will break  the F-Stop  aka Aperture number and Aperture
opening down for you and Aperture should start to make sense to you.


F-Stop is seen as f[numerical
value] e.g. f2  F-Stop is actually
an equation that reads”F” is for Focal length divided
by the aperture number equals the aperture opening.  

What is focal length? Is not the length of your lens but the distance in millimeters from the optical center of the lens to the sensor when the lens is focused to infinity? Still confused.. well think of it in reference to perspective. Let’s say for example a focal length of 50mm on a full frame sensor is similar in perspective as the human eye. If you use a focal length greater than 50mm then the subject is magnified from normal perspective and when the focal length is less than 50mm the image is widened from normal perspective.

Let’s say for example the focal length is “200mm” and the aperture number is “2” . Using the equation focal length of 200 divided by 2
equals an aperture opening of 100.
If the focal length is “200mm” and the aperture number is “22” then the
aperture opening is 9.09. So as you can see this is the reason why an f2 has a
larger opening than an f22.


LEARNING TIP:  Remember since
“f” is a variable you can’t assume that if you always set your aperture to use
a 2.0 and lower f number you would get a shallow depth of field.

Now that the F-stop makes sense to you we can proceed with
the uses of aperture to apply what you’ve learned.


There are two main uses . #1
Creative and #2 Functional


1. Bokeh Lights
– This creative use of “bokeh lights” is
basically an image where you see lights in the background blurred and of
different shape to what they would normally look when focused.

a.   To get this bokeh
lights effect, you would need to use a low number fstop
like 1.4 or 2.0 and focus on a subject that is only a few feet from you and the
background of lights about 10 feet behind the subject.  If you followed my instructions correctly,
then you should be able to replicate the image below.

Fotodiox Wonderpana bokeh lights photo

photo credit:

2. Sparkling light – This creative use of “Sparkling light” is basically an image
where you are able to see the rays from a light source which makes it appear

a.   To get this sparkling light effect, you would need
to now use a high number fstop like 16 or 22. If you
followed my instructions correctly, then you should be able to replicate the
image below.

Aperture sparkle light effect photo

photo credit:

LEARNING TIP: Use your eye’s to help determine which creative use is best for
your image. What I mean is that try to replicate the aperture setting with your
eyes. To test bokeh lights, you simply make a fist
and place your fist 4 inches from your left eye and focus on your hand and then
make sure there are lights in the background. You should now be able to see the
bokeh lights. Now to get a visual of how the “Sparkling light” will look, you’ll simply need to squint to the point where it is almost
closed and look at the lights and you should be able to see the rays of light.

Now that you know the main creative uses of aperture, let’s
look at the more functional uses of aperture that is mainly seen in a lot of
aperture tutorials.


1. Isolate the subject by using a long focal length
of light 200mm and a small aperture number of 2.8 to achieve a shallow depth of
field and isolate the subject.

a.   Isolation functional use of aperture is commonly
used for Portraiture, Product Shots and Macro Photography.


photo credit:

2. Everything in Focus can be achieved by using a
short focal length like 14mm and a large aperture number of 22.

a.   All in focus functional use of aperture is
commonly used for group photos and landscapes.

Aperture all in focus example photo

photo credit:

LEARNING TIP: Remember to depend on your vision as
this will guide you into determining the focal length and aperture number for
your desired look.  Here are some
examples: If you are In a grounding environment and is causing too much
distraction away from the subject, then you will need to ensure for a very
shallow depth of field. If you are trying to take an image of a landscape, then
you will need to ensure that everything foreground, middle ground and
background is in focus.

Now that you’ve completed this tutorial on Aperture change from program mode to Aperture Priority mode and go out
and try to replicate all of the creative and functional uses to help
communicate your concept or story.

NOW Move out of PROGRAM MODE and change setting to APERTURE PRIORITY.


If you enjoyed this tutorial, then please make sure you sign
up for the PhotographySILO In-Crowd Newsletter. I will
be emailing the free Tutorial on Aperture to my newsletter subscribers as a
thank you and newsletter subscribers will be notified once the next free
tutorial is available to view on

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About the Author

Lawrence Atienza is a Jack of all Trades and Master of ALL. Whether it be in the realm of Advertising/Advertising operations with over 10+ years of experience to dabbling in the creative realm of photography and founding/writing for, Lawrence Atienza gives his all. You can find him on Google+,Twitter and the major social media outlets.