Hello again, let’s dive right in. When you look at getting a new digital camera be it mobile phone camera, pocket camera, bridge/mirrorless or DSLR one of the first things you’ll come across is how many megapixels does it have. So the big decision then is how many megapixels you’re going to get, isn’t it? Well no, not all megapixels are the same. Umm, what?
So why, aren’t megapixels all the same, isn’t more megapixels better than less? Before we dive into this question let’s look at where megapixels live inside the camera. The heart of the camera is the main capturing device inside, the sensor. Now you might not have thought about this but the sensor inside different cameras can be all of different sizes, have a look at this diagram you can see that there are a whole range of different coloured boxes which represent the different sensor sizes. In the bottom left-hand corner (yellow) you have some of the more popular mobile telephone brands such as the Samsung Galaxy (Note 4) and iPhone 6. In the top right-hand corner you go all the way up to (red) the medium format and in blue the full frame 35mm DSLR image sensor common in high end DSLRs. Other popular sizes you may hear about APS-C and Micro Four Thirds which are between these two extremes (black and pink).
What that means is that if you were to look at Nikon DSLR cameras you’ll find the FX which is a full frame sensor is 35 mm but the DX models are a crop size sensor, the APS-C sensor which is 23 mm on the longer side. Cannon cameras are similar between their full frame versions (5D/1D bodies) and crop frame versions (7D, 70D and x0D bodies). You’ll find that many of the various pocket cameras have a range of sensors commonly around Micro Four Thirds all the way down to those common in mobile phone cameras that on average range at 4 to 5 mm on the long side.
So what does it mean to megapixels, well look at this way if you have a camera with a sensor that’s just smaller than 5 mm long side and it says is 18 megapixels and you have a camera say the Nikon 1CX it sensor at 13.2mm long, for the same megapixels it is nearly three times as big but capturing the same image size. This means that the resolving area of the megapixel in the camera is that much smaller as the sensor size decrease, remember, there is always give and take. This means that they are trying to jam more information into a smaller space. This can mean that you lose some details and fine resolution although the megapixels are the same. You can what appears to be a pleasing image but can be limited when editing or zooming in when compared to an image from a larger sensor. In a future article we will talk about image resolution which will help explain this.
Right, so that means that cameras with more megapixels on the same size sensor is better, yes? Well, maybe not. This is a bit more difficult to get your head around, looking at say the Canon 5D Mk III you’ll find it’s a full frame camera with a 22.3 megapixel sensor, a great camera with lots of megapixels. But the next professional camera up in the range is the Canon 1DX Mark 2 which was released in late 2016 but it’s only 20.2 megapixels twice as expensive, a professional version but has less megapixels. Nikon cameras are the same if you look at their high selling Nikon D810 which is a 36 megapixels beauty and their flagship professional camera the Nikon D5, also released mid-2016, its only 21 megapixels. So what gives?
Well, this comes down to the size of the cells/elements that make up the sensor itself. Simply put the high-end cameras although they may have smaller megapixel sensors the imaging cells parts that makeup the sensor are actually larger in size which allows a better resolution, sharpness, colour space and dynamic range than the higher megapixel versions. These might not mean a lot to you but what it does mean is that there is more information captured for each part of the image. The next camera down such as the Canon 5D Mk III may capture more megapixels but it is trading off some of this higher quality picture information to achieve those extra megapixels. One of the common things you’ll hear in photography is that you can win in one place such as shutter speed or aperture to capture light but you’re trading them off against each other so for every win something is lost.
Thinking megapixels, don’t always believe that more is always the answer then. When you go to compare cameras you need to maybe consider the size of the sensor together with a number of megapixels, the smaller the camera, in general, the smaller the sensor size may well be. When you are comparing say and iPhone 6 to an iPhone 7 or any camera you may be getting more megapixels in the sensor may be nearly the same size but there may be other development changes that may have improved the sensor, so you may actually gain information.
Ultimately comes down to what you will use image for, the camera of your mobile telephone may catch a nice image, you may be able to look at it happily on the screen on your phone, you might also be happy to do some editing on your phone. If you are not printing large photos does it do everything you want, do you really need more? If you drive in the city, do you need a car that can cruise at 200 kilometre per hour, do you need an off-road 4x4 if you never leave the suburbs? Looks at what you are happy with, if it does everything you want and more, you might already have found the camera best suited for you.
This is a key part of the camera, the next main consideration in small cameras, how does the camera zoom is and out, close-up vs wide, but that’s for next time. See you then.