Camera lenses explained for beginners – 15 things you need to know. Hi, and welcome to Episode 57 of the Photography Explained Podcast. I’m Rick, and in each episode I will explain one photographic thing in plain English in less than 10 minutes (ish) without the irrelevant detail.

What I tell you is based on my lifetime of photographic experience, not Google, mainly this is stuff that I know.

And when I say 10 minutes, this episode is not looking good. There’s quite a lot to explain here.

I am going to go into quite a few of these things in future episodes. I’ve spent some time on cameras. Lenses – it’s a big area really. The bit you shove on your camera that you take photos through, so quite important!

You can listen to the episode here

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

Camera lenses explained for beginners – 10 things you need to know.

That’s what it was when I started writing this, and it ended up being 15. And it could have been 16 as I forgot one thing. OK, it is 16.

1 Why are there so many different lenses?

If you look on the internet and look at camera lenses, it’s a bit bewildering. I mean, I use Canon cameras and lenses. Look at the range of Canon lenses, and it’s quite, yeah, it is bewildering. There are so many different lenses.

And if you think about them, these are expensive things, so they’ve been made for a specific reason. For every lens that you can see, you might not have a need to use one yourself, but for every lens that’s ever been made (pretty much) there was a purpose for it, and somebody spent a lot of time and effort and engineering genius creating it. And a lot of money.

We have fixed lenses and zoom lenses. This is fundamental point number one.

2 Fixed lenses

With a fixed lens, you look through the lens and you see what you see. On a zoom lens, you can zoom in or out.

Fixed lenses are also called prime lenses. I don’t know why.

But a prime lens will have a focal length, for example of 50mm. A 50mm lens is what is called a standard lens. I’ll come back to that (but use this to explain things).

3 Zoom lens

A zoom lens could be, for argument’s sake, 24-70mm, a variable focal length. I will come back to this.

4 Standard Lens

Right then. A standard lens has a 50mm (focal length) on a full-frame camera, I will come back to crop factors.

This is the thing that I sort of love and hate about photography all at the same time. I can’t seem to explain one thing without having to explain five other things. So I can’t just explain a lens without going through these other things.

If it sounds like I’m jumping about all over the place, there is a reason for it, and it’s because none of these things is that straightforward. I’m trying to make them straightforward and understandable.

Standard lens on a full-frame camera.

Now I explained in an earlier episode what a full-frame camera is, but let’s just do a quick recap. A full-frame camera has a sensor which is 36mm x 24mm, which is the same size as a 35mm camera film.

You put a 50mm (standard) lens on a full-frame camera and what you see through the viewfinder is pretty much how humans see the world (certainly me – I cannot vouch for you!).

So a standard lens is you photographing things how we see them as we walk about our day-to-day business.

5 Wide angle lens.

A standard lens on a full-frame camera is 50mm.

A wide-angle lens is less than 50mm (focal length), common focal lengths are 24mm, 28mm, 35mm. Anything beyond 35/40mm and you’re getting towards standard but 24mm and 28mm are very common wide-angle lens focal lengths.

Now what does this mean?

With a wide-angle lens, because your field of view is wider you can see more. So rather than what you’re looking at and you can generally see, you’ve got a wider view, there’s more to be seen there’s more in the scene. And everything is generally smaller and farther away.

6 Telephoto lenses

A telephoto lens has a focal length which is longer than 50mm (a bigger number). With a telephoto lens, common focal lengths could be 135mm, 200mm, 300mm, or 400mm. The bigger the number, the more magnification, the closer you get to things, and the less your field of view (and the more they cost).

So that’s a telephoto lens.

Sets of lenses

So if we go back to fixed lenses, as I say, you could have a set of lenses which are 24mm, 28mm, 35mm, 50mm, 85mm, 135mm, 200mm, and 300mm.

Before zoom lenses that would have been quite a common set of lenses.

You could, however, get a zoom lens, I’ve got a Canon 24-105mm lens which goes from wide to telephoto, which is a really good all-round lens. This is why we have zoom lenses as they give you us more options than having fixed lenses.

Post-episode recording note – My Canon 24-105mm lens replaces, in theory, the 24mm, 28mm, 35mm, 50mm, and 85mm lenses – get the point? This is one of the points of zoom lenses, 3, 4, and 5 lenses in one.

7 Crop factor

Now I said at the beginning 50 millimetres on a full-frame camera is (pretty much) how we see the world, the same aspect ratio, the same everything.

Now if you get a cropped sensor camera, also known as APS-C (check out previous episodes for more on this) there is a crop factor applied because the sensor is smaller.

On a cropped sensor camera, the common crop factors are 1.5-1.6 x.

What that means is this.

You multiply the focal length on a full-frame camera (50mm) by 1.5, and that gives you an effective focal length with a 50mm lens on a cropped sensor camera of 75mm.

How did we end up with this – baffling isn’t it?

Micro Four Thirds cameras have even smaller sensors. And the crop factor on a Micro Four Thirds camera is two.

So a 50mm lens on a Micro Four Thirds camera gives you an effective focal length of 100mm.

Okay, I’ll come back to some of these in more detail (in future episodes not here).

8 Other specialist lenses

There are specialist lenses which are not that common which I’ve owned, used and sold again.

Fisheye lens.

They give you a circular image. I spent about a grand on a fisheye zoom lens, the Canon 8-15mm lens. So at 8mm, you get a fully circular image, at 15mm you had a normal full-frame aspect ratio image (but very wide).

Sure, I got some funky effects with it, but I didn’t really need it, so I sold it.

Tilt Shift Lens

I’ve also had a tilt-shift lens, complicated, manual focus, big, heavy expensive. I had a go with it, but it’s also been sold on, which is a shock considering I’m an architectural photographer.

But I get by.

9 Aperture.

Another thing in a lens. Now when you buy a lens, and I’m going to stick with my 50mm example, you have a maximum aperture, and the maximum aperture is the maximum opening that lets the most light in.

So if you have a 50mm lens. Let’s go with a 50mm F1.8 lens. F/1.8 is the maximum aperture. The aperture is a thing in the lens that reduces the size of the opening in the lens letting less light in. The minimum aperture, the smallest opening, letting the least amount of light in, will be something like f/22.

So that lens will cost you more than a 50mm F4 lens. The bigger the maximum aperture, the more light that gets in through the lens to the sensor, the “faster” the lens, and the more expensive it is. And the bigger and heavier it is too.

If you take photos on a tripod like me, it’s not a big issue anyway. So yeah, the larger the maximum aperture, the bigger and more expensive (and perceived higher quality don’t necessarily believe that) the lens is.

10 Depth of field

Depth of field is a term I hate. It’s the amount of the photo that’s sharp from front to back.

Now the aperture (of the camera lens) is a factor. The aperture and the lens focal length have an impact on the depth of field.

If you have the camera lens wide open, as in maximum aperture (largest opening), you will get less depth of field. If you stop down the lens to the minimum aperture, (the smallest opening), you will have more depth of field.

You get more depth of field on a wide-angle lens than you do on an (incoming telephone call!) telephoto lens.

You get more depth of field on a crop sensor camera than a full-frame camera, I still don’t understand that.

11 Quality

Okay, quality of lenses. I think in general terms, the more money you pay, the higher the quality, the better the photos, in general terms.

This is a big generalisation in photography because you can get fantastic photos with a camera and lens costing £1,000.

So why can you buy a camera (and lens) costing £10,000? Because the quality is higher. So the more money you spend, the higher the quality, but you can get really good results with relatively inexpensive lenses.

These days, the optics are fantastic. There’s also a lot of clever electronic stuff in the software that helps as well.

So yep, quality varies, and cost varies hugely as well – it depends on what the lens is. As I say the bigger the maximum aperture, the more expensive the lens.

Post-episode note – I will compare prime and zoom lenses in a future episode.

12 Cost – what do I use?

Now, I use a Canon 17-40mm F4 lens. It is not a fast lens. Because it’s an F4 maximum aperture lens, the lens isn’t that big, it’s not that expensive.

And it takes fantastic photos, it works for me.

17mm is wide enough, just what I need, and I take most of my photos using 17mm. And I never take photos at f4.

The problem with maximum and minimum apertures

You lose quality at both ends of the aperture scale, I use F8 or F16 – the bits in the middle (the sweet spots for this lens).

So that’s what I use.

I don’t need a more expensive camera lens with a bigger aperture because I’ve just got no need for it. And it would just be a waste of money and it will be heavier. So think about that and the type of photography you’re embarking on

13 Resale value.

No one told me this. Nobody ever told me this. I had to find this out myself. If you buy a camera lens, in five years’ time you might well get more money for it.

They hold their value fantastically well.

Just something to bear in mind.

I’ve actually bought secondhand lenses, had them for 4,5, 6 years, used them a lot, looked after them of course, so they’re in immaculate condition, and sold them and got really good money for them.

So yeah, bear that in mind.

14 Does every camera have interchangeable lenses?

No, they do not – you can get cameras which do not have interchangeable lenses.

Let me introduce a new, unhelpful acronym – ILC. Interchangeable lens camera – it’s a completely unnecessary term, isn’t it?

15 Camera mounts

Canon has its own (lens) mount, as do Nikon and Sony, Fuji and others.

Micro Four Thirds cameras have a universal mount though so you can use an Olympus lens on a Panasonic Micro Four Thirds camera and vice verse.

But there are third-party lens manufacturers who make lenses for all makes and types of cameras.

16 What do I use?

I use three lenses.

• Canon 17-40mm F4L
• Canon 24-105mm F4L
• Canon 70- 200F4L IS USM (a snappy title I know)
• I used to have a 24mm tilt shift lens – I sold that.
• I used to have a 100-400mm zoom lens – I sold that.
• I used to have a 100mm f 2.8 macro lens – I sold that.
• (And I forgot to mention that I used to have a Canon 8-15mm fisheye zoom lens that I also sold).

I probably had other lenses, especially in my earlier crop sensor days, but they’re all gone.

I only have three lenses.

With my Olympus EM5 Mk2, I have

• 14-42mm lens, a pancake lens. That fits the camera in my camera pocket (really)
• 12-40mm F2.8 lens which is a brute.
• And a 40-150mm lens.

That’s all I have.

Right? I am way over time here. I thought so.

My one-line explanation.

Camera lenses provide endless creative opportunities for photographers.

The next episode is Episode 58 would you believe – prime lenses explained by me in plain English in less than 10 minutes – snappy title

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I’ve been Rick McEvoy thanks again very much for listening and for giving me 16 ¼ minutes of your valuable – the longest episode ever. And I’ll see you in the next episode.

Cheers from me, Rick.

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