Hi, everybody, welcome to Episode 23 of the photography explained podcast. In this episode, what is aperture in photography?
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 us with our photography and no more.
Now I just noticed a bit of a flaw in my erm, my opening text because I'm doing this twice weekly. So I'm actually explaining two photographic things in plain English in less than 10 minutes without the irrelevant details in a week, not one.
Will I carry on and do that in the new year? Who knows? I was thinking of going to once a week, but I'm not gonna lie to you. I do actually enjoy this.
Right, let's get on
What is aperture in photography? This as Jeremy Clarkson would say, is my answer.
In photography, when we talk about the aperture, we're referring to the opening in the camera lens through which light passes when you take a photo. The aperture combined with the camera shutter controls the amount of light that reaches the camera sensor when you take a photo.
Okay, I know I'm talking about exposure in general here, but I really should have mentioned that ISO is the other part of the exposure triangle, apologies for that omission (not emission!). ISO is the sensitivity of the sensor to light.
Okay, so about camera aperture.
Let's have a look at this in a little bit more detail. Not too much, but enough. So you understand. And as it turns out, so I understand because I got a few things wrong on this, which was a little bit, well, let's just say that I thought I knew more than I did.
So I had to do some actual work and research on this one. Which is good, because that was always going to be part of the process of the podcast. I can just sit there for 10 minutes and tell you all about this, that and the other. But when I start writing my notes, yes, believe it or not, I do prep these episodes, I find gaps in my knowledge.
So I've enjoyed finding those gaps and filling them and hopefully giving you a complete and correct answer, but just enough.
Okay, then what is the aperture made of?
Obviously, camera lenses are made of all sorts of stuff, polycarbonate plastic, glass for the optics, metal bits here and there. I told you I didn't want to get too technical. But what is the aperture actually made off?
Now then I have written to Olympus, Canon, and Sony. And you know what? They wouldn't tell me. I'm surprised at that. So I can tell you is that they are probably metal. I can't do any more. I can't tell you which metal - can't say anything more about them.
Seems like it's a bit of a trade secret, which was a bit of a surprise to me. Let’s hope we have a bit more joy with my question to these guys about what's the shutter made of – not holding any hopes to be honest with you.
The actual aperture
You need to look at a picture of a camera aperture or get your camera and stop down the aperture and you can see it making the hole smaller. That's the important part of this.
If I use for an example, a camera lens, a 50 millimetre F2 lens, F2 is the maximum aperture. F2 is the aperture fully open. So that's as much light as you can get into the camera lens.
There is something called an aperture scale.
This is yet another of these things that if we were inventing photography now, we wouldn't have come up with this between us – well I hope we wouldn't.
So what is the aperture scale?
This is a range, I'll give you the range of numbers first, and then I will explain them.
So this is the aperture scale in full stops
F1.4, F2, F2.8, F4, F 5.6, F8, F11, F16, F22.
I hope you're still awake. That was dull.
So why these numbers?
Well, if you look into it, there's a number of different explanations for these numbers and to be honest with you, they don't help so I'm going to move on from that. That's not important. But let me tell you something.
This is very important.
Now, you could accuse me of oversimplifying this, but I just want to explain it, so you understand it.
Going with my example of a 50 mm F2 lens, F2is the small number that is the maximum aperture. So, a smaller number means a larger aperture setting, which means a larger hole, which means more light getting in, and you also get less depth of field.
Now, this is obviously a generalisation, but this is the important principle, larger numbers equals a smaller aperture settings equals a smaller hole. I've actually written this wrong in my notes (but corrected it here)!
- So larger numbers, a larger aperture setting, a smaller hole, less light, more depth of field.
That's the that's the takeaway. And this is the first time I've used that term.
The smaller number, the larger the aperture, the more light that gets in.
The larger the number, the smaller the aperture, the less light that gets in.
Who came up with this?
Someone who's probably too clever for their own good and needed a hobby, but didn't find one?
What are F stops? Oh, I don't really know, let's not worry about them. If you look on Google, some will say the F stops are apertures. I don't think that's right. Or the say it's the ratio of the focal length and the lens – this could be right. And this is a bit baffling.
Doesn't matter. larger number, smaller number. more light, less light. That's what matters.
Obviously, there's things like depth of field which I will cover separately.
What are half stops?
Well, I have helpfully written in my notes here, the bits in the middle.
Why can I change the aperture?
Well on a camera, you change the aperture to change the amount of light that gets to the camera sensor. Now let's assume you haven't changed the ISO (the sensitivity of the sensor). If you wanted to use an example, I'm going to get this wrong - I always do.
If you had an exposure of 1/500th of a second at F8.
If you wanted to use a faster shutter speed as in 1,000th of a second, that would be letting half as much light in. So what you do is you change your aperture from F8 to F5.6, which is a full stop. And that will give you the correct exposure with different settings.
So that's one of the important parts of the exposure triangle. So the aperture is changeable.
Now what about an iPhone?
I have not spoken about phones much, but they also have an aperture. Now I'm sure there's clever things that can recreate changing apertures computationally now, which is a lot more advanced and different.
But I currently have an iPhone XS and the aperture on that lens is F 1.8.
Okay, so I think I'm done here. What I wanted to get over and what I wanted you to understand was the simple principle.
- Small number, larger hole, more light
- Larger number, smaller hole, less light.
That's the important part of aperture.
Okay, I'm going to stop there. I was in danger of saying something else and which would have been a risk of confusing things.
So what's next? Well the logical next thing which will be in Episode 24 of the Photography Explained podcast. What does shutter mean in photography? Let's do this in a logical order.
Thank you
Okay, thank you for listening. I hope you enjoyed this episode. I hope I've explained it. If you did, please leave a nice review and rating wherever you get your podcast from. And please subscribe so you don't miss an episode.
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Yeah, you can also check out my website Rick McEvoy Photography where you can find out all about me. I nearly got through an episode then without getting my words wrong!
Check out my website where you can find out all about me, my construction, photography work, my architectural photography work, and all the good stuff I write about on my blog. You can also find all my podcast episodes there. You'll also find a list of future subjects which probably needs an update now. Finally, if you want me to explain something to you, let me know – just go to my website where you will find loads of ways to get in touch.
Let me know what it is you want me to explain and I will add it to my list on my website. And when I do it, I will give you a shout out and a link to your website if you have one.
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We're nearly there. I’ve been Rick McEvoy, thank you again for listening and giving me 10 minutes of your valuable time. I will see you on the next episode. Cheers from me, Rick.”