What Is A Zoom Lens Explained In Plain English In Less Than 10 Minutes


Hi, and welcome to Episode 59 of the photography explained podcast. I’m your host, Rick, and in each episode I will explain one photographic thing in plain English in less than 10 minutes without the irrelevant details.

What I tell you is based on my lifetime of photographic experience, not Google, this is stuff that I know. And this being about zoom lenses, it is stuff that I know so there was no research required, which is always good, makes me feel a little bit better about myself.

Right then. So what is a zoom lens? Here is the answery bit

A zoom lens is a camera lens that has a variable focal length. Zoom lenses offer photographers greater flexibility over fixed or prime lenses. Zoom lenses enable photographers to carry fewer camera lenses due to the variable focal lengths, and change lenses less often. Zoom lenses can provide excellent-quality images.

Now I have to say here that zoom lenses can provide rubbish images, but so-called prime lenses can also, and that is normally down to the photographer and not the lens (interesting digression).

You can listen to the episode here

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

What are the types of lenses?

Well, the other type I covered in Episode 58 is prime lenses. I don’t like the term prime lenses. I call them fixed lenses. Check out the last episode for more.

Why are they called zoom lenses?

Well, prime wasn’t clear. Not that it matters, to be honest with you. But Zoom makes sense. This makes a change in photography.

You zoom in, you zoom out, sorted, we get it.

Do zoom lenses take better photos than prime lenses?

It depends on the quality of the lenses that you’re comparing. If you got oh, I don’t know, a five grand fixed (prime) Leica lens and compared it to £100 kit lens with a zoom, then you will get a better (quality) photo with the fixed lens.

If you compare a five grand zoom lens with a £100 fixed (prime – see I call them fixed incorrectly!) lens, you will probably get a better (quality) photo from the zoom lens.

If you compared similar quality lenses, you would probably get better image quality with the prime lens than you will with the zoom lens – as a generality, when you’re making a sensible comparison.

So that doesn’t mean zoom lenses are (or are not) better than prime lenses, it means that prime lenses probably give you a higher quality photo.

But the next question will answer the burning question I’m sure you all have.

Can you actually tell the difference?

Well, when you are making a like-for-like comparison, most people probably won’t notice.

So why should you not use a prime lens?

(Keeping this in as it made me smile – I remember struggling here!

Or as I could also have said – So why should you not use a zoom lens?

Why should you use a prime lens?

Well, if you’re doing massive prints, the same thing with medium format cameras, if you do massive prints like billboards, posters, huge things that people can get close and look at, then you’d want the sharpest lens you could get, and you’d want the largest sensor thinking about it.

If you’re after the ultimate image quality prime lenses are for you. And there is nothing wrong with that.

If you’re a normal person, like me (I like to think) then you should be fine in zoom land, zoom lenses these days are really good. They give you great image quality.

So why should you not use a zoom lens?

I don’t use prime lenses, to be honest with you, but I’ll get onto that.

How much do zoom lenses cost?

Depends (of course) – it depends on the focal length of the lens, and this is relative to the number of lenses that you can replace. I come on to this shortly as well.

I use a Canon 24-105mm lens. Now that’s just taken out the need (in theory) for me to have the following lenses

  • 24mm
  • 28mm
  • 35mm
  • 50mm
  • 85mm
  • 105mm

That is six lenses (in theory) that I don’t need. I say in theory because I need to let you into a secret.

Now, I actually use 24mm and 105mm, and not often the bits in the middle. So you could say I’m a prime contender for prime lenses – oh the irony. I’ve just thought about that never came to me before. Should I be using prime lenses?

Yes, I probably should. And I’m going to compound that theory even more (in a bit). Right – let’s get back on track.

What are the advantages of zoom lenses?

You have different focal lengths, as I’ve just described, and you can get great image quality. If you buy a rubbish zoom lens, you won’t get as good quality as if you buy a really good zoom lens. But that’s no different to prime lenses.

You can get great image quality with zoom lenses, you get more flexibility.

Changing lenses – you don’t have to do it as often, or in my case at all. I work on construction sites, in very dusty environments, and I don’t really want to be changing my lenses on the site.

As it happens, I don’t because I use my 17-40mm lens. I don’t use anything else on shoots. I’m all right.

So every time you need a different focal length, you have to change the lens.

And finally, you need more gear.

What are the disadvantages of zoom lenses?

Well, they are bigger and heavier, they have moving parts, and there’s more to go wrong.

They can be expensive.

And you probably get a smaller maximum aperture with a zoom lens, which reduces your options when you’re taking photos handheld.

Basically, if you think about the zoom lens, you’ve got stuff, optical stuff moving in and out and all over the place to very cleverly change the focal length but keep the focus and everything working – incredibly complex things.

And like I say there are moving parts so there is more to go wrong.

Spoiler alert – I have never (touching wood and everything wooden including my head), I’ve never had an optical problem with a zoom lens, I use Canon L series zoom lenses, or as some people like to call them glass. I hate that term.

So what are the most common focal lengths of zoom lenses?

Well, this is what I have

  • 17-40mm
  • 24-105mm
  • 70-200mm

I don’t use prime lenses anymore, I sold them all because I didn’t use them. I didn’t use them because I didn’t need them.

Now the maximum aperture on these three lenses is f4. I take most of my photos, 95% on a tripod. So I’m not concerned about having a fast lens with a large maximum aperture, it doesn’t affect me. And if you’re a landscape photographer, you’d be in the same boat – you don’t need it (a larger maximum aperture).

I take most of my photos at F8 anyway, so yeah, I don’t need prime lenses.

The case for me having a prime lens

Now I might get slightly better image quality (with prime lenses). Sure I might, if I had them – I want to get back to the point I made earlier on.

I use my Canon 17-40mm lens on my Canon 6D for virtually all my architectural photography work. I’ll say virtually – every now and then I’ll find something that I want to get closer into to get a detail of, or to isolate things, and then I use the 70-200 lens.

But I use the 17-40 and I probably take, I don’t know, 80 to 90% of the photos at 17mm. It’s become subconscious (this was never a plan), it’s become a bit of a thing, taking photos at 17mm.

As I mentioned before, I also use a 24-105mm lens and tend to use the 24mm or 105mm ends of the 24-105mm lens, I don’t tend to use the bits in the middle.

If Canon did a 17mm F4L lens I might go with that, might give it a try

And the case for not?

What I like about the 17-40 lens is this. I look at my composition, and if I need to just zoom in a little bit, I can do it. I don’t think I’ve ever taken a photo at 40mm. Can’t remember.

So obviously there are many, many other focal lengths available and there are some fantastic zoom lenses out there.

And again, massive generalisation, but the more money you pay, the better the quality of the lens. But having the best lens in the world doesn’t guarantee great photos.

You can have the best lens in the world and take rubbish photos. Let’s not forget that. Right then. Not too bad on time again, quite happy with that.

My one-line explanation.

Zoom lenses offer photographers different focal lengths in one lens, giving photographers more options and possibilities with less gear.

One more thing – less gear is good. More gear is bad. That’s my personal opinion.

Next Episode

Episode 60. I’m in the 60s, fantastic – kit lenses explained by me in plain English in less than 10 minutes. Kit lenses it’s a simple thing.

But I still want to explain it. I was going to shoehorn kit lenses into zoom lenses and I thought no, no, no, let’s just keep them separate so I can explain each one. This is where I’ve been going wrong with stuff before.

I’m going to talk about Ken Lay kit lenses (what the transcript came up with). And before I record the next episode, I am going to sit down in a dark room and say kit lenses, kit lenses kit lenses until I don’t make a mistake.

What Is A Kit Lens? What You Need To Know Without The Irrelevant Detail!

Right nearly done.

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Thank you

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And also the Photography Explained Podcast website where you can find out all about this podcast and ask me a question of your own.

This episode is brought to you by the power of caffeine and just one take which I’m delighted with.

I’ve been Rick McEvoy. Thanks again very much for listening and for giving me 12 and three-quarter minutes of your valuable time. And I will see you in the next episode.

Cheers from me, Rick.

OK – that was the podcast episode.

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Thank you

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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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