5 Practical Applications Of The Exposure Triangle


Hi, everybody. Welcome to Episode 28 of the photography explained podcast. In this episode five practical explanations of the exposure triangle.

I’m your host, Rick, and each week, I will try to explain one photographic thing to you in plain English in less than 10 minutes without the irrelevant details. My aim is to explain things in just enough detail to help you and I with our photography and no more.

Nope, still can’t remember it and am still reading out the intro!

So five practical applications of the exposure triangle.

In this episode, I’m going to give you five practical examples of the exposure triangle. Apologies for repeating myself there. These examples tell you how to use the exposure triangle to correct a photo that is too light and one that is too dark. I also tell you how to use the exposure triangle to get a correct exposure with a faster and slower shutter speed. I’ll tell you what I do as well.

  1. You took a photo, but this is too dark. So what do you do?
  2. You took a photo that is too light, here’s what you do.
  3. You want to make moving things blurry but get the exposure correct.
  4. You want to freeze the action.
  5. How do I use the exposure triangle?

You can listen to the episode here

Or keep on reading. Or do both. Entirely up to you!

Okay, let’s go straight into these five examples.

Now I’m not gonna lie to you. I’m reading these out because I’ve written them down because what I found is when I tried to record this I always got something wrong. So I’m reading these out, and I’m not apologising for it, because this is the good stuff, trust me.

1 – You took a photo, but this is too dark. So what do you do?

Take another photo, but this time use a slower shutter speed to let more light in. Alternatively, choose a wider aperture, (which is a smaller number of course) to let more light in.

If you don’t want to change the settings increase the ISO to make the sensor more sensitive to light (in theory).

Okay, that’s the first one. I wanted to give you these practical examples because having spoken so much about it, you might be sat there going “OK, well, that’s great, but what do I do if my photos are too dark? So that’s why I’m doing this, which is nice.

2 – You took a photo that is too light, here’s what you do.

Take another photo and this time pick a faster shutter speed to let less light in. Alternatively, choose a smaller aperture (larger number) to let less light in, as the lens opening is smaller in physical size

If you don’t want to change these settings, reduce the ISO to make the sensor less sensitive to light (in theory).

OK, that’s one way of dealing with underexposed photos, and overexposed photos.

In the next episode, I’m going to talk about exposure compensation, which is a different and easier way of doing the same thing. You can do this without taking the camera away from your eyes, which is good. And the logical thing to get on to then is going to be speaking about the different picture-taking modes, which I’ll get onto shortly.

I know it’s complicated

As you’ll see, I can’t explain one thing in photography without having to refer to something else – nothing seems to stand alone. So each of these subjects is naturally leading on to another one which is great when I try and come up with episodes to record.

So back to the subject – here are three other practical uses of the exposure triangle.

3 – You want to make moving things blurry but get the exposure correct.

First, you need to choose a longer shutter speed which means more light is getting into the sensor as the shutter is open for longer, let’s say one second to blur a waterfall. Once you’ve done this, you’ll need to choose a smaller aperture (larger number) which lets less light in to compensate for this.

If you cannot get the correct exposure for the lighting conditions by changing the aperture you can then select a lower ISO – yes this is an ISO with a smaller number.

A quick word on a filter that can help

If this does not work, you might need to select a faster shutter speed and then re-meter or use a filter to block the amount of light getting into the sensor. I’ll come on to this in a future episode but just so you know you can have a look at this now if you want.

Neutral Density Filters

These filters, which reduce the amount of light getting to the sensor, are called neutral density filters.

I have one (ND Filter) which is called a Lee Big Stopper, which gives a whopping 10-stop reduction in the light that gets through to the sensor. If you go back to previous episodes and check out the aperture scales and shutter scales, you’ll see what massive impact this has.

Tripods are a must here

If you’re going to make things blurry, but keep the photo sharp you need to put your camera on a tripad, A tripad? No a tripod. A tripad is a tripod and an iPad, I think I’ve made this mistake before but I’ve invented a new product – a tripad   – I should try and sell that to Apple. Why not?

Back to the subject. Sorry.

4 – You want to freeze the action.

Well, this is the reverse of the above. You need to choose a shutter speed that is fast enough to freeze what you’re photographing. This will of course depend on what you’re photographing. If you’re photographing an F1 car, you will need a faster shutter speed than say someone walking quickly.

When you choose a faster shutter speed, each time you change the shutter speed by a full stop you are halving the amount of light getting to the sensor.

What do I mean by that? Well check out the last episode where I explain the exposure triangle. Each time you change the shutter speed by a stop, you need to change the aperture by one stop to maintain the correct exposure.

I know this is a little bit complicated but think of it like this.

Each time you make the shutter speed faster, less light is getting through to the sensor. So you need to choose a larger aperture (smaller number, bigger opening) to let more light in.

And if you can’t get a fast enough shutter speed by changing the aperture, all you have left to do is increase the ISO (changing to a bigger number), which is making the sensor more sensitive to light (in theory).

Okay, nearly there on this one.

5 – How do I use the exposure triangle?

Well, I’m going to finish this episode by telling how I use the exposure triangle in my architectural and construction photography work. Yeah, everything today might sound complicated, but the reality can be different. It’s important that you understand how these things work and relate though.

But I want to reassure you, once you have got your nut around all these things, it should be relatively straightforward.

This is what I do

I take my architectural, construction and real estate photography photos with a Canon 6D. I use AV mode (where I select the aperture and the camera selects the shutter speed). AV stands for aperture value, also known as aperture priority.

I use the lowest native ISO normally (one for another episode) which is ISO100. And most of the time my camera is on a tripod.

I set the aperture to suit what I’m photographing, which is normally F8 or F16, and take photos using the camera self-timer.

And that’s it.

The aperture I choose is determined by the composition.

The camera does all the clever work. So let’s not forget as complicated as cameras are these days, they are wonderful things that can help us.

But we still need to understand this stuff

It does help if you know what you’re doing because if you do you can simplify things. The hard bit is getting your head around some of these things.

Quick recap.

In this episode, I’ve given you five practical applications of the exposure triangle which I hope you found helpful.

Now I want you to do some things.

1 – Do this one thing.

Just try one of the five things above.

2 – Tell me how it went on Twitter.

Message me on Twitter @rickphoto.

3 – Subscribe to my podcast

If you enjoyed this episode please – this helps me tremendously.

4 – Rate and review my podcast

If you’ve enjoyed this episode that is – this also helps me.

5 – Tell someone you know about my podcast.

This also helps me and it doesn’t cost anything.

Next episode I do believe is exposure compensation.

Okay, times nearly up.

Thank you for listening to my small but perfectly formed podcast. Check out my website Rick McEvoy Photography, where you can find out all about me and my architectural and construction photography work, as well as my photography blog where you can learn lots more about photography, and about me.

Last thing folks

Finally, let me know if there is a photography thing you want me to explain and I will add it to my list. Just head over to my website and click on the podcast tile. And if I explain your thing, I will give you a shout-out on that episode. The list is now live on my website for all to see.

This episode is brought to you by the power of me sitting in a small room without being distracted.

1000 downloads

One thing I want to say is I’m delighted to announce that I have achieved 1000 downloads. So thank you to everybody who is downloading my podcast – that really is a massive number for me. It might not sound big to some people, but it makes me happy. So thank you to everyone who’s downloaded my podcast.

I’ve been Rick McEvoy. Thanks again for listening to me and for giving me 10 minutes of your valuable time. I’ll see you on the next episode.

Cheers from me, Rick

OK – that was the podcast episode.

Want to know more?

Head over to the Start page on the Photography Explained Podcast website to find out more.

And here is the list of episodes published to date – you can listen to any episode straight from this page which is nice.

Let me know if there is a photography thing that you want me to explain and I will add it to my list. Just head over to the This is my list of things to explain page of this website to see what is on there already.

Let me send you stuff

I send out a weekly email to my subscribers. It is my take on one photography thing, plus what I have been writing and talking about. Just fill in the box and you can get my weekly photographic musings straight to your inbox. Which is nice.

And finally a little bit about me

Finally, yes this paragraph is all about me – check out my Rick McEvoy Photography website to find out more about me and my architectural, construction, real estate and travel photography work. I also write about general photography stuff, all in plain English without the irrelevant detail.

Thank you

Thanks for listening to my podcast (if you did) and reading this blog post (which I assume you have done as you are reading this).

Cheers from me Rick

Rick McEvoy Photography

Rick McEvoy

I am the creator of the Photography Explained podcast. I am a photographer, podcaster and blogger. I am professionally qualified in both photography and construction. I have over 30 years of photography expereience and specialise in architectural photography and construction photography.

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