I’ve thought about covering off some of the basic principles of photography a few times on this website, but often find myself coming to the conclusion that someone else will have done a better job. The problem is, when I’m asked questions about some of the basics, most of the links I find online are so heavily based on digital photography, that I worry they create confusion in those looking to approach learning photography via analogue mediums.

As such, nearly 6 years into running this website, I thought I might put together a few articles on some of the basic principles of photography from, but talk about them in the context of analogue rather than digital. This first article is to focus on three key variables in photography: shutter speed, aperture and ISO (film speed), and the relationship between them.


The first thing to understand about these three variables is that if you strip a camera back to its most basic function, shutter speed, aperture and film speed are the only things beyond light itself that you need to understand to take a photo. These three variables amount to what’s called “Exposure”.

Exposure defines how light or dark a photo will be. With there being three variables, the relationship between them is often referred to as the “Exposure Triangle”. By understanding the exposure triangle it is not only possible to achieve correct exposure, but it also opens the up doors to creativity within photography.

It’s worth noting at this stage that the concept of “Correct Exposure” is a very deep hole – so for the sake of this post, let’s just assume we always want to achieve an even distribution of light, mid and dark tones across our photo.  This is about the most simple definition of correct exposure I can think of. As a definition, it overlooks many potential creative goals – but the point is here, to obtain the correct exposure, it is important to understand all three of the key variables, and indeed the relationship between them.

But, before we get to the relationship between them, it’s useful to understand how each one of the variables has a different impact on how your photo will look. To understand how they impact the photo, the best place to start is to understand what they do and how they work.


Source (https://www.35mmc.com)