“You don’t take a photograph just with a camera. You bring to the act of photography all the pictures you have seen, the books you have read, the music you have heard, the people you have loved.” – Ansel Adams
Photography Course Basics – Do Megapixels Matter?
A major selling point for new cameras and smartphones is a high megapixel count. The manufacturers and distributors of new devices want us to believe that the higher the count the better, justifying their higher prices. But do those pixels really add up? Do you ever need 20+ megapixels, and is the quality of the imagery any better as result?
As many photographers have said before, the camera does not take the photo, the photographer does. Before worrying about equipment you should always get the basics down by taking a photography course, and once you know how to craft a photo you can start looking into optimising your camera’s specifications.
What is a “megapixel”?
In digital photography there is a measure of resolution called “megapixel” (MP), a pixel is a small dot on the sensor of the camera that captures light and mega stands for a million, so a megapixel is a million pixels (resolution of 1000×1000 pixels).
Simplified, the camera sensor consists of a fixed amount of pixels, and the higher the number the higher the resolution. However, this does not always translate to a better picture as there is another factor: the size of the individual pixels themselves.
A common analogy is to compare individual pixels to buckets, each capturing a fixed amount of light. With a small bucket you will capture less light than with a large one, and this is exactly how pixels work. Bigger individual pixels = more light captured = higher-quality picture.
In most smartphones the sensor is about 4.8 x 3.6 mm, whereas a typical DSLR sensor will measure 22.3 x 14.9 mm. If both the phone and the camera are 5 MP, the difference in sensor size indicates a very significant difference in pixel size – so guess which one can captures more light (hint: it’s the DSLR).
So how many megapixels do you need?
Depending on what you are going to use your photos for, there is usually no need for anything more than 7 MP. Most social media (Facebook, Instagram, Twitter) downsize the images you share so if that is your goal, you need about 1-3 MP. For large-scale prints of 28x35cm (11×14 inches) it would be safe to say that you don’t need more than 14 MP. For huge posters, 22 MP is usually enough, as you normally stand further away from the photo and won’t notice any loss in sharpness. For a quick reference you can use the following equation to estimate what resolution you need for a print:
(WIDTH in inches x 300) x (HEIGHT in inches x 300) / 1 million
So don’t pay over the odds because of a high megapixel count, and consider the sensor size v pixel count instead – although whatever equipment you have, you’ll still need a good eye and solid technical grounding.