All about Aperture February Issue

2/2/2015

What is Aperture and how do I use it?

February Issue

All about Aperture

What is Aperture and how do I use it?

Funnily enough, this is the question that I get asked the most for advice on, but people who ask don't realise that this is what they are asking for advice on.

So what is aperture? Aperture relates to how far open the iris of you camera is. Now for anyone that isn't sure what is the iris of your camera. It is the part in your lens that controls how much light is let through to your camera body. You can change how far this opens with the aperture setting and this will affect how long the shutter is open, this can also affect the ISO setting (we will look at shutter speed & ISO in future newsletters) You just need to know for now that they are all related to each other.
You can see below how different aperture settings change how far open the iris is. Funnily the smaller the number, the larger the opening in the iris. But I'll explain why shortly.

So how do you use the aperture setting on your camera. On Canon cameras the setting is "AV" on Nikon, Sony and most other cameras it is just "A". When you are looking at your display screen or through your lens it appears on your screen as a f-number, as seen below in the circle.

So why does a smaller number make the hole larger? It is because the number refers to a ratio between the focal distance and the opening diameter of the iris. The way I think of it so I can remember how it works is, at F/1.8 only the first 1.8 meters of the photo is in focus at f/22 the first 22 meters of the photo is in focus (and this isn't how it works but it helps me remember, and the distance I have stated is just to help remember how it works, this is not the actual focal range).

So how does it work? You can think of it this way, close your eyes then open then and close them as quick as you can while looking at the picture to the left. Do you remember much of what you just saw, you maybe know it was a picture of some buildings in Venice, correct.
Ok, now this time just have a good look at the picture. Did you see the couple going for a ride in the gondola last time? So this is kind of how aperture works. Basically when the iris is fully open, like f/1.8 in the image of the lenses above, there is much more light going onto the sensor therefore the camera only opens the shutter for a short period of time,

(assuming the weather is the same as in the picture of Venice above). What this means is, like when you opened and closed your eyes quickly. The camera doesn't have much time to pick up all the details in the background. So only the item that you made the focal point will be in focus, like in a setting of f2.8 on the camera. See Picture 1 below.
But if you choose an aperture like f/22 because this is such a small hole, the shutter must stay open for longer to let the same amount of light in to get the same exposure. Therefore the sensor has a lot longer to collect the light and therefore the details of the objects in the background. As seen in picture 2 below.

f2.8

Picture 1

f22

Picture 2

I hope you have enjoyed this months' topic "All about Aperture". Please share this with any of your friends you think it may benefit.

And if you have any topics you would like me to cover in future editions of "Photography Tips" please feel free to contact me by any of the means below.

If you have any topics you would like covered, you can contact me either by commenting on my Blog which is on both www.thebooth.com.au and www.brendanfellowsphotography.com or by leaving me a message on one of my Facebook pages https://www.facebook.com/TheBoothSydney or https://www.facebook.com/brendanfellowsphotography . I look forward to hearing from you.

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