Why Is Camera Sensor Size Important?


Hi, everybody, welcome to episode eight of the photography explained podcast. In this episode, why is camera sensor size important?

I’m your host, Rick, and each week I’ll try and explain one photographic thing to you in plain English in less than 10 minutes without the irrelevant details. Blimey, a bit of a mouthful.

My aim is to explain things in just enough detail to help us with our photography and no more. Today I am trying an experiment on this episode recording in my office, which might be a bit bouncy and echoey. But I’m hoping that the technology will be able to deal with that.

Let’s see how we get on with it.

Why is camera sensor size important?

The size of the camera sensor size defines the type of camera, the most popular ones being full frame, APS-C or micro four-third cameras. The size of the camera sensor is a significant factor in the quality of images captured, with larger camera sensors generally recording more data and providing higher-quality images. The size of the camera sensor is related to the cost of the camera – generally the larger the sensor the more expensive the camera.

You can listen to the episode here

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

This is one of those fundamental things, to be honest with you. Incredibly confusing. It is just the way that photography has evolved over the years, meaning the size of a sensor pretty much determines what type of camera it is.

Now, let me explain that. I’m not pretending to talk about every possible camera out there. I mentioned most of the camera types in a previous episode. I want to focus on the main cameras available for us normal folks.

I’m excluding all the large format or the really expensive massive things, and medium format cameras. I’m going with, like I say, cameras that normal people can buy.

Three camera types determined by sensor size (missing from the spoken episode!)

Now there are three different types of normal cameras that people can buy.

First, they are sorry, I’ll just tell you what they are first. These are

  • Full frame camera
  • Cropped sensor (or APS-C camera)
  • Micro Four Thirds camera

Now these three different types of cameras all have one fundamental difference. That is that the sensor is of a different size.

How big are the sensors? Full frame camera

Okay, so I use a Canon 6D for my architectural and construction photography.

The sensor size is 36x24mm.

Other full-frame cameras will have slightly different dimensions, but the point is, that’s the size of a full-frame sensor. Now this rather bizarrely equates to the size of a film negative from back in the camera film days.

So we’ve ended up taking the dimensions of a negative and making an entire range of cameras with a sensor of the same size.

How big are the sensors? Cropped sensor/ APS-C camera

Moving on cropped sensor/ APS-C cameras. APS-C is a baffling term that shouldn’t exist (in my opinion). It goes back to the Advanced Photo System, which was another camera film thing. But the thing we need to know is an APS-C sensor is smaller than a full-frame camera sensor.

A cropped sensor/ APS-C sensor is 25.1×16.7mm

Yep, there are variances from this again, but that’s the overall general dimension.

I should just call these cropped sensor cameras.

How big are the sensors? Micro Four Thirds camera

Now micro four-thirds is a completely different system. A Micro Four Thirds camera sensor (according to Mark Thackara at Olympus UK) is

8×13.5mm.

Let’s just go through these again.

  • Full frame sensor – 36x24mm
  • APS-C sensor – 25.1×16.7mm
  • Micro Four Thirds sensor – 18×13.5mm

The actual dimensions can vary slightly from manufacturer to manufacturer.

But the general point is this. A full-frame sensor is the biggest sensor of conventional consumer cameras. A cropped sensor/ APS-C sensor is smaller, and a Micro Four Thirds sensor is smaller still.

So what does full frame mean?

I’ve explained that

What does APS-C mean?

I’ve explained that.

What does Micro Four Thirds mean?

Not going to lie to you? I haven’t got a clue.

APS-C I didn’t really explain – it doesn’t really matter. It’s just a term from the past. That’s irrelevant detail to me.

Without the irrelevant detail.

The origins of these sensor sizes are to me irrelevant detail. Knowing where the term micro four-thirds comes from does not help me explain the different sizes of sensors.

A cropped sensor is a cropped sensor. APS-C could be called Bob and it would not make any difference to me. 

A full-frame sensor is bigger than a cropped sensor/ APS-C, which is bigger than a micro four-thirds sensor.

So what does this actually mean?

Well, in general terms, the bigger the sensor, the bigger the camera, and in general terms, the bigger the camera and the bigger the sensor the more expensive the camera is.

In even broader terms, the bigger the sensor, the better the camera.

I am not saying that a full-frame camera is better than a Micro Four Thirds camera. They’re just different. They’re different sizes. Do you need to get hung up on this? Not really. But it does determine which camera to buy.

Other things that matter

There are lots of other influences caused by camera sensor size such as the focal length. With a full-frame camera, 50mm is termed a standard lens. A 50mm focal length on a full-frame camera relates to how you see things with your eyes.

Crop factors introduced

You put a 50mm lens on a cropped sensor/ APS-C camera and its focal length is in effect 80mm, slightly telephoto. You put a 50mm lens on a Micro Four Thirds camera and it gives a focal length of 100mm effective focal length.

There are other things, these are the fundamentals.

General camera systems.

Yeah, sensors are expensive things to make. So the bigger the sensor (in general terms), the more expensive the camera will be.

Right, my notes run out there. I’ve got lots more to say on this. So we’re gonna go for a bit of an ad-lib.

What do I use in my architectural and construction photography?

I use a full-frame Canon 6D. It’s quite big, well it’s not huge, but it’s quite big and inconvenient. And I don’t like taking on holiday and using it. So I bought an Olympus Micro Four Thirds camera, the Olympus EM5 Mk 2, which is a lot smaller.

Is it smaller?

Then again, I put a lens on it like the 12-40mm F 2.8 and it becomes a bit of a lump anyway. But if I put the pancake lens on, I can pretty much get that camera in my pocket. It’s brilliant. And the photos are fantastic too. This takes me to the next ad-lib question.

Can you get better photos with a full-frame camera than you can with an APS-C or Micro Four Thirds camera?

I think the general answer is possibly. But having a bigger, better camera doesn’t mean you’re gonna take bigger better photos. Did I say bigger photos? Of course, you will. But that’s another issue of file sizes and what have you.

You can have the best camera in the world and still take rubbish photos, you can have a very average camera and take a great photo.

That’s not the point here. But what I wanted to get over was what these different camera sensors are, why this is so important when choosing a camera and what the different camera systems are.

Money

Like I say Micro Four Thirds cameras tend to be smaller. So if we’re comparing similar performing cameras, micro four-thirds cameras tend to be cheaper than cropped sensor cameras, which tend to be cheaper than full frame cameras.

Obviously, each manufacturer has many different models and many different prices (or as others like to say price points).

Hopefully, you’ve got it by now.

Do I need to go into any more detail on this?

The answer is no. Because I’ve not written any more. I haven’t got anything more to say on this because I think that the point I wanted to make I’ve made which is full frame, cropped sensor and micro four thirds (not microphones as the transcript reads) are different camera systems with different sizes of sensors.

Take your pick.

They’re all brilliant these days – it really is hard to buy a bad camera. Seriously is so yep, that’s that one done.

Next on the photography explained podcast. How do I learn to use my camera? I think that’s what I’m doing. I might change the order. Tell you what, let’s wait till Thursday and find out.

Thank you

Thank you very much for listening. I hope you’ve enjoyed this episode. I enjoyed this one. It was nice to explain this. If you did enjoy it, please leave a nice review and rating wherever you get your podcasts from. And also please subscribe so you don’t miss any episodes. And if you could also tell everyone you know about my podcast that would be even better and I will be very grateful.

You can also 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 blog where you can learn lots more about photography. Yes, I’m reading this bit off the page. I really need to learn this off by heart, don’t I?

Last thing – if you want me to explain something, head over to my website. Post podcast episode note – the Photography Explained Podcast website. Head over to my website, send me an email, tell me what your question is and I’ll add it to the list and that will be that.

What’s next? In the next Photography Explained Podcast Episode 9 – How Can I Learn To Use My New Camera?

Thank you very much for listening. See you on the next one.

I’ve been Rick. Bye

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.

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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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