I’ve been meaning to cover off what stops of light are in photography and how you can use your stops knowledge to help you out, but other things have come up. Never fear, I’ve covered it here!

A video of everything you may need to know about stops can be found below, but let me just say that this video features a major boo-boo on my part in the form of an example image. We are all human and mistakes happen, even by me (usually by me) and therefore, please be a nice person when you see my disastrous photograph, ok?

Let’s start at the top:

What are stops of light?

Essentially, stops are what photographers use to measure how much light or how little light we have. If you’ve ever heard or seen me say/write, “you could do with an extra stop of light” or “you’re about one stop over here” then I am talking about this hypothetical (but also very real) measurement of light.

How do stops of light work?

In a nutshell, stops of light work in doubles or halves. So if you need 1 stop of light, you can halve your shutter speed to get it. Or double your ISO. Or halve your F-Number. If it seems like I’m speaking Latin, you might need to go and brush up on your exposure triangle knowledge here.

Just like you can get a full stop by halving one thing, you can also get a full stop by taking a quarter off of two things. It works in fractions.

To get a half stop of light, just work out a quarter of your chosen setting and take it off what you’ve got. For example, if you’re on 1/1000s and you want half a stop more light, work out a quarter of 1000 = 250, and take it off of 1000 = 1/750s.

How do stops of light help me?

If you know the maths around stops, you can critically assess a poor shoot in terms of exposure and work out what you can do next time to get the shot well exposed, whilst not compromising your settings. The same can be done on the fly, on location. So if you think, “Oops, this shot is about 1 stop underexposed here, what can I do?”, think back to your exposure triangle and work out which settings you can alter to regain that full stop of exposure back.

In the video, you’ll see a photo of Alfie which, through Lightroom, we worked out was 2.5 stops underexposed. Yes, you read that right. Yes, I didn’t check. Yes, it was a disaster.

So we did some maths, pulled back 3 stops and then tactically lost a stop to reduce our ISO.

I then went out and re-shot at those new settings, at the same time of day, and the photograph was well exposed and completely usable.

Job done. That’s stops!