Megapixels Explained

The new Galaxy S20 offers a 64-megapixel camera, the iPhone 12 a 12-megapixel camera, the Sony Cybershot digital camera has 20 megapixels.

So, how many Megapixels (MPs) do you need? Do more pixels mean better photos?

Well, here’s the scoop!

First, how they are determined –

Well, the term “megapixel” simply means 1 million pixels. So, that means a 20 MP camera can capture 20 million pixels at its highest quality setting. The more of these pixels you capture, the larger you can print your image. Stop and re-read that last sentence! It’s the main reason for wanting more megapixels.

Alright then, how many MP are you going to need to print the size photos you want to print? Well, it depends on how large you want to print and at what resolution. Now, stick with me here…

Between 300 and 600 DPI is usually considered “photo quality”.

In order to print a 4×6 at 300 DPI, you need to take the length and multiply it by the resolution, then do the same with the width. Next, multiply those results. Don’t worry, this is much easier than it sounds:

4 (width) x 300 (resolution) = 1200

6 (length) x 300 (resolution) = 1800

Those are your minimum width and length pixel counts. To print a 300 DPI photo-quality 4×6, you would need an image that was 1200 x 1800 pixels. Now, to determine how many MP this is:

1200 x 1800 = 2,160,000

Not too bad. Now we know a 3 MP camera can make a good 4×6 print at 300 DPI. Now, if you want a 600 DPI print, you’ll find after re-running the numbers you’ll need a 5 MP camera to do the same job! Goes up fast, doesn’t it?

Here’s an example to illustrate this. Let’s say you take the same photo with both a 12 MP camera and a 20MP camera. Now, you go home and make a 4×6 from each camera. Guess what? You won’t be able to tell the difference. And any differences you could detect are probably due to sensor and lens differences. Heck, it’s possible the 12 MP camera would give you better results if it had a better image sensor and lens than the 20MP camera!

You see, megapixels alone don’t determine quality and sharpness. They’re simply a measure of resolution—how many dots make up your image. Picture quality and sharpness are determined by the quality of your sensor and lens.

For instance, you can go out and buy that new 20MP camera. Sure, it’s going to capture high resolution images, but if the lens is of poor quality, all you’ll end up with is high resolution images that are not overly sharp and have no fine detail. If the lens isn’t capturing fine detail, you can bet your sensor won’t either.

Your best bet is to stick with name brands and read the reviews.

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