Kevs quick guide to megapixels!
How many megapixels do you need?
Someone told me they were super excited to get a 42 megapixel camera recently. They were super excited because these 42 megapixels were in a camera phone, WOW. It was sure to produce amazing images right?
Megapixels 101! A megapixel is a term used to describe quantity, not quality. It’s a number that represents how many light collectors are on the camera’s sensor. An 8 megapixel camera packs 8 million pixels into your photo. So more is better right? 16 megapixels would double our pixels and therefore be a better sensor in a camera! Well not so fast…
Let’s think about light as if it were rain, falling out of the sky. We want to catch as much of it as we can. If I have 8 million 1 gallon buckets on the ground they will catch the rain as it falls. I should get a lot of water with 8 million buckets! But my friend just got a 42 megapixel camera and he wants to go catch rain too! When he sets out to catch the rain he actually has 42 million shot glasses (he has a smaller area on the sensor to gather the light since it’s packed into the phone). My buckets from home depot are going to collect more light than his shot glasses, even though he has 42 million of them.
I have created an intense graphic to demonstrate this:
Image sensors come in different sizes, the larger the sensor the larger the pixels can be. Bigger pixels can collect more photons (rain in our example). A 42 megapixel smart phone packs those pixels on to a sensor no larger than the size of a penny. One way to see the quality of a sensor to look at others reviews. Before you purchase a camera check out rating sites like this one: http://www.dxomark.com/Cameras
This blog post is a very basic summary of megapixels and there is a lot more you can learn out on the web there. Remember that megapixel measures quantity, not quality, when you look at cameras. More megapixels is generally a good thing, but it also depends on the size and quality of your pixels.