Beyond the Basics Overview of Tafe Southport course Night 2

Tonight was about the relationship between ISO, Aperture and Shutter Speed. 

Two and a Half hours of the relationship. Quick rant = Would this NOT have been covered in the basics course? Rant ends.

The biggest issue I believe beginners have with these three things (the ONLY things that dictate exposure, which excludes white balance, coz WB is about colour and not exposure) is that the three terms are foreign to you. That’s it.

Here is how I like to explain a perfect exposure. Let’s say that an empty bucket is what you have at the start of an exposure and what you want is the bucket to be full of water, without overflowing, for a perfect exposure. You take a hose and you turn on the tap so the velocity of water (in photography terms = ISO / film speed) will not change (ie the brightness of the light) over the exposure. Using your garden hose (half inch, small (eg. f22) compared to a fire hose, (eg. f4) and it takes say 30 seconds (shutter speed – how long the tap is turned on / shutter open) to fill the bucket perfectly. Nice pic right, perfectly exposed. Let’s say though that you want to fill the bucket faster.  So would you use a BIGGER diameter HOSE (aperture) or a smaller one? Let’s say you get a hose that has twice the opening surface area … now it will take half as long to fill the bucket? The same goes with photography.

That’s it folks. Stop over thinking it. If you change the aperture by x, you change the shutter speed (the other way) by the same amount. No. Stop. That’s it. No. Stop thinking. That is as complicated as it gets.


As to the effect that changing the Shutter Speed and or Aperture has, well that’s got nothing to do with exposure, it has to do with your creative desire.

Bucket of water. Full.



bucket of water

bucket of water

PS. Think of aperture numbers as 1/22 for f22 and 1/4 for f4.  Is 1/22 bigger or smaller than 1/4.?