Quantity of light

Quantity of light

The quantity of light is probably the easiest concept for people to grasp.  Essentially it determines what exposure settings you need in your camera, and – if adding light – how much power you need from your flash or added light source.

Essentially this reduces to balancing how much light there is available, versus how much light you want to let fall on your sensor for the duration of time that the shutter is open. 

For a wedding photographer in Ireland, it’s rare to have too much light, but it can happen, especially when adding light yourself.  More common is a sense of there being too little light, but what I hope to convey throughout this blog is that there is rarely actually too little light. Given a choice, I’d often opt for too little light rather than too much, because it can be really hard to take light away, but it’s often possible to add light.

When we create light we will endeavour to independently control the quantity of ambient light versus the quantity of added light. Learning how to do this is the key to creating your own light, and will be a major focus of this blog.

There’s an important aspect to the quantity of light that needs to be highlighted, though – I mentioned above that quantity is often the easiest concept for people to grasp. I believe that’s why the two most common questions I get asked if I show a photograph are:

  • What were your camera settings?
  • What power was your flash at?

Because quantity is the easy bit, conceptually, it’s easy to fall into the trap of thinking that once you know how to control quantity, you’re able to replicate a shot. The reality couldn’t be more different. If you stick at this for long enough, you’ll find that in time you’re able to do two things quite intuitively. Firstly, you’ll get good at estimating shutter speed, aperture and ISO for a given scene. Maybe not nailing the exposure, but enough to be within a margin of error that some processing work can deal with. Secondly, you’ll get good at approximating how much power you need from a flash to add light. Those skills will, in many cases, come long before the skill of knowing where to put a light, or – perhaps crucially – why to put a light.

So do yourself a favour – next time you see a photo which has light that catches your eye, don’t ask the photographer about camera settings or flash power. Ask about where is the light coming from and, if added by the photographer, why was it added, and why was it added there?

In the detailed breakdowns that I’ll be offering occasionally on this blog, I’ll focus on those aspects more than anything. When it comes to exposure and flash power – more often than not my answer to the question of “what are they?” will be – the right ones. But – and this is the most important thing – if you stick with learning all about this topic, either here or elsewhere, you’ll quickly be comfortable with finding the right exposure, and finding the right flash power.

So in short, when it comes to quantity of light, be aware it’s a characteristic and be able to assess it, but please don’t dwell on it. There are far more important aspects deserve your attention to make a good photograph. In fact, of all the characteristics, quantity is the one that your flash and camera would, if left in automatic mode, take a pretty good stab at figuring out all by themselves.