How Does ISO, F-stop, and Shutter Speed all work together?

ISO, Aperture, and Shutter Speed all play together.
How do they all play together? Well follow close and I'll do my best to try and explain.. and if you have your camera with you you'll know what I'm talking about.

As explained in my last post ISO was how sensitive your camera is to light, Aperture was how much light your lens was allowing in, and Shutter Speed is the length it takes to take the picture. These three elements took me quite a long time to understand how they work together, especially when I had nobody to show me how things work. So if you don't understand it right off the bat, no worries, just experiment and it'll come to you with time and practice.

Lets start it off: Having a low ISO (lets say 100) will make your camera have a lower Shutter Speed. Easier put, lower ISO=lower Shutter Speed.

Now, having an Aperture of 22 (remember that means the lens will be letting in little amount of light) will make your Shutter Speed lower as well. Lower Aperture= Lower Shutter Speed

Here is an example*:

As you can see, as the Shutter Speed reduces (while keeping the same Aperture) the picture gets brighter because your camera is allowing more time for light to come in.

Wonder how people get water to look like mist? They make waterfalls and waves look like they are moving in the picture? Many people like myself years and years ago went, "oh that's just Photoshop, duh!". Well, no.
If you can use what I explained above, you can create "long exposures" to make beautiful pictures that not even your brain can capture in real life. Though there are many methods of how to create a long exposure, I'm going to tell you the most basic.

Materials needed for Long Exposure:
-Camera
-Tri-pod
-Low ISO (100)
-High Aperture # (F/22+)
-Low Shutter Speed (1/25-->1 second)

ISO 200, Shutter Speed of 3 seconds, and F/22. I was able to achieve such a long exposure because I wasn't facing the sun, using a low ISO, a high F/#, allowing me to create a 3 second Shutter Speed.

In my later tutorials I will explain what filters are and how they can be used to create very long exposures during the day.



*http://www.shortcourses.com/use/using1-8.html