The truth about megapixels
/I am going to go out on a limb here and say that anyone that owns a digital camera is familiar with the term megapixels, perhaps that was even the reason you purchased the camera you currently have or why you upgrade your smart phone when new version comes out. But do you really know what megapixels are, and what they do, and do not do, for your photography or viewing pleasure?
In this article I am going to explain exactly what megapixels are and debunk some myths and explain where megapixels really shine.
Understanding megapixels
If you are not familiar with what a pixel is then let us start there. A pixel (px), is a small area of illumination on a display screen such as a computer screen, smart phone, tablet or a TV. The pixels can vary in size depending on the image resolution of the device screen and the device screen physical size. If it helps, for the purpose of this article think of pixels as the smallest physical measurement you can think of like millimetres (mm).
Say you have a square that is 1000px x 1000px. This means the square is made up of 1000px on it’s width and 1000px on it’s height.
What are megapixels?
Now that we have a rough idea what a pixel is, what is megapixels then? Is it a gigantic square pixels with some superior magic added to it?
No it is not of the sorts I am afraid, it is simply, another unit of measure. More specifically, megapixels simply define the image area of effective pixels.
Megapixel is a unit of measure that defines the image area where mega means million.
Let's take that 1000px x 1000px square and calculate how many megapixels (MP) it has.
1000px • 1000px = 1,000,000 px = 1 MP
A megapixel is an area measurement where Mega = Million pixels and measures the image area.
In our example this instead of saying 1 million pixels we say 1 MegaPixel (MP). Likewise, rather than saying a camera has 24 million pixels they are branded as 24 MP and it sounds way cooler too, doesn’t it?
Megapixels in photography
With the advent of digital cameras manufacturers have pushed the megapixel count higher and higher with every new camera they release. This is a good thing as it pushes technology forward and if we look at it historically, my first digital camera I used in school had somewhere around 0.4 MP and took 1.44 MB floppy disks. If manufactures hadn't pushed the megapixel count we would all still be shooting using analog film.
But do you really need the increased MP? Let us compare how the technology we use today measure up against what our cameras are capable of producing.
| Device | Image Resolution | Image Area (total px) | Megapixels (MP) |
|---|---|---|---|
| 720p HD Ready TV | 1280 x 720 px | 921600 px | 0.92 MP |
| 1080p Full HDTV | 1920 x 1080 px | 2073600 px | 2.07 MP |
| 4K UHD Monitor/TV | 3840 x 2160 px | 8294400 px | 8.29 MP |
| iPhone 7 | 750 x 1334 px | 1000500 px | 1 MP |
| iPad Pro | 1024 x 1366 px | 1398784 px | 1.41 MP |
| Samsung Galaxy S7 | 2560 × 1440 | 3686400 px | 3.69 MP |
| MacBook Pro 15” Retina | 2880 x 1800 | 5184000 px | 5.18 MP |
None of the current technologies even comes close to the resolution provided by our cameras which today ranges from 24MP to 100MP when we include medium format cameras.
You may still be able to find 12MP and 16MP cameras from some manufacturers, but they are pretty much gone from the market by now.
Even worse when uploading to social networks that usually have a maximum allowed size that cuts the MP count down even further. Instagram’s 1080px x 1080px equals to 1.2 MP. So why do we need such high MP on our cameras when nothing else even compares? There has to be something more to it right?
Megapixel myths
Due to megapixels becoming such a huge sales pitch myths surrounding megapixels quickly started to evolve. Lets debunk some of them now.
More MP means better camera
This is like saying buying a bigger cooker will make you a better chef. It’s not the camera and most certainly not more MP that makes a great photo, it is you, the photographer, your lens selection and lighting skills, the camera is only a tool.
More details in a photo
While we record more information to the digital file, this doesn’t always mean there are more details in a photo. A full frame camera with lower MP will record more information than a APC-S or Micro Four Thirds camera with more MP will do. This is because the full frame camera’s sensor is that much larger and can record more details in shadow and highlight areas.
Better contrast and colours
The contrast and colour of a photo has to do with lens selection and sensor size and how the software in the camera processes and develops the photo (when shooting in JPEG). When shooting RAW (which I hope you do), you are responsible for development of the photo including contrast and colour treatment.
Sharper photos
The reason your photo looks sharper at higher MP is because our computer screens cannot show it at full size. Just like the small screen on the back of our cameras can fool us into thinking we nailed the focus, only to discover we didn’t when looking at it at 100% on a lager screen. Everything looks sharper when it is viewed in a smaller size.
When megapixels actually matters
We’ve come to the point where MP really shine and more MP will actually help. You might have already figured it out. Since MP is just an area measurement it come very well into play for two things; cropping and printing.
Cropping
If you can’t get close enough to your subject with the lens you have, the extra MP will allow you to crop-in on the photo to get closer to the framing you originally wanted without losing too much resolution in the photo. This can be handy when shooting animal at a zoo or safari.
Cropping result in loss of resolution and extreme cropping will start to introduce noise and your image will appear blurry even with a high MP camera. It is much better to get the framing of your subject right in-camera instead.
Printing
More MP gives you a larger image area which translates to larger physical measurements, which means you can do larger prints at higher print resolutions without needing to enlarge the photo up to a point. This is also why you want to refrain from cropping your photos, as it will affect the size print you can make.
The takeaway
In the early days MP needed to increase so we could even have a chance to print a decent sized photo or display it large online. It became a sales pitch and rightly so, later MP surpassed what a computer monitor is capable of displaying but the sales pitch stayed even to this day which is partly to blame for people relating MP to thinking they are getting a better camera, while in may have been true ones, it is far from true with todays technology.
So unless you are in the habit or business of printing your photos large or at high print resolution, you don’t really need that 42.4MP camera when you only show your photos online or on a computer screen with a current standard of 2 - 8 MP.
If you find yourself in the camera store trying to decide between two cameras that are similar in specifications, or perhaps even the same, don’t choose based on the MP count (unless there is a valid reason), choose the one with less MP if it saves you money, and instead spend the extra money on a better lens, a tripod or other accessories for your camera.
Thanks for reading and please share this article if you enjoyed it.
Until next time, go get pixelated!
