How important are camera megapixels (print & post images online)

There was a time, a long time ago, when camera megapixels was an important selling point. So it was relevant for camera manufacturers to develop cameras with greater megapixel counts and to promote a camera by quoting the megapixel count.

But that was many megapixels ago and I’ll tell you why it’s no longer a reason to buy a new camera. Let’s take a look at:

  • What’s a megapixel?
  • How do megapixels relate to resolution?
  • Do more megapixels mean better quality photos?
  • How much do megapixels matter?

how high camera megapixels enables cropping model portrait

What exactly is a megapixel?

Photos are made up of pixels and a megapixel is simply one million pixels. So a 24 MP (megapixel) camera has 24 megapixels and the images it produces have 24 million pixels.

Working out the exact megapixels of an image is the same as working out the area of a room…

Multiply the pixel length of the photo by the pixel width of the photo. Then divide that by 1 million to get the number of megapixels of an image.

For example:

Image dimensions are 3,872 megapixels wide x 2,592 megapixels high = 10,036,224 pixels.

Divide by 1 million = 10 megapixels. (It’s not an exact measurement)

full size low megapixel image of fairground game

I photographed this image on a 10 megapixel camera. (Side note – I have no idea why I keep some of the photos I do. I captured this in 2008 on a Nikon D80!)

Resolution and camera megapixels

The number of pixels, also known as pixel count, determines resolution and you’ll have come across the 3 different types of resolution. They are:

  • Image resolution (as discussed) – the number of horizontal and vertical pixels of an image
  • Screen resolution – the number of pixels per inch (PPI) to give resolutions of 720p, 1080p 4K etc
  • Print resolution – the number of pixels per inch (PPI) or dots per inch (DPI), usually 200 – 300

Do more megapixels mean better photo quality?

No, a camera with more megapixels definitely does not create better quality photos.

To create the best quality photo possible the three essential ingredients a photographer controls are:

  • Sharp focus
  • Accurate exposure
  • Compose in camera (i.e. no cropping)

Sharp focus

Despite all the amazing technology we now have for sharpening images, an accidentally out of focus image will never be as good as it could have been if it was in focus and therefore already sharp.

Accurate exposure

Heavily overexposed and underexposed images, even if you shoot in RAW file format, always lose quality when corrected in post production.

Composing in camera

When you crop a photo you throw away pixels. If you print the cropped version and the uncropped version to the same size, the uncropped version will be better as it’ll have more pixels to fill up the print.

So in this instance, aside from camera settings, your gear will have an impact on image quality. BUT it’s not as important as getting the shot right! So don’t think that getting a “better” camera is going to make you a better photographer.

Pixel count reduced by cropping fairground duck image

Above you can see how much I cropped the duck photo and below is the result.

The cropped version measures: 3,872 pixels wide x 1,713 pixels high = 4,383,567 pixels. Divide by 1 million = 4.4 megapixels.

That’s less than half the megapixels of the original photo! And it was taken on a low megapixel camera. But it looks fine.

cropped low megapixel image of fairground game

How gear affects image quality:

  • Lens quality
  • Sensor size

Lens quality

The quality of materials used in more expensive, quality lenses has an effect on image quality. This is why professionals and serious amateurs opt for more expensive lenses.

Sensor size

A camera’s sensor size also has a big impact on the quality of an image in so far as bigger sensors have more pixels than smaller sensors. More pixels equals more detail captured and more low light sensitivity.

If you crop an image taken with a 36 MP camera versus the same crop on an image taken with a 12 MP camera, you’ll still have more pixels. So you can print the cropped image bigger when you have more megapixels to play with.

Another way of looking at it is that the more megapixels you have, the tighter you can crop an image without it looking bad. BUT I really wouldn’t recommend that as a reason to get a camera with more megapixels.

How much do megapixels matter in cameras?

Unless you shoot commercially, or print large images, you don’t need a high megapixel camera.

In fact you can actually have too many megapixels.

What? Yes. Here’s how…

Capturing high megapixel images

Capturing a series of images in burst mode on a high megapixel camera makes the camera work a lot harder than a low megapixel camera.

All that memory takes a lot of processing. So your high frame rate might be affected, depending on the quality of the camera. Your camera might also need to pause capturing to buffer the images before you can continue. In which case, you could miss the moment.

Plus, all those images will need processing, which leads to my next point on camera megapixels…

Processing high megapixel images

Cameras with a high megapixels create (uncropped) images with high megapixels and the more megapixels an image has, the larger it is in terms of memory. That ultimately leads to needing more storage – memory cards as well as hard drive storage.

Not only will your hard drive fill up sooner, but it’ll take longer to load images to your computer and longer to work on them. It may just be a second or so longer to open an image with a high pixel count, but if you have loads of images to process, every second counts.

Many wedding photographers, for example, shoot thousands of photos per wedding.

Let’s just say you have 2000 images to cull and process. If only 1 second is added to the time it takes to open an image that’s 2000 seconds, which translates to 33 minutes! Just to do a first pass look through of all the images! Before you even begin to cull images or process your photoshoot.

If your computer isn’t really up to date and fast it will take even longer.

Exporting and transferring/uploading images is also affected by the memory size of the image. So every step of the post production process is impacted by the number of megapixels in an image.

Posting high megapixel images online

Megapixels are wasted online!

The majority of people use their phones to go online so the images they see are so small that it’s a complete waste of pixels. Even tablets and computers are too small to fully appreciate a high megapixel image.

Aside from that, all social media platforms compress images, so by the time they’re visible online, the image quality has been wrecked.

Even worse – bigger images (i.e. the ones that are high in megapixels and therefore memory) are compressed even more.

And it’s not just social media. If you upload images to a website, you have to:

Now, because higher megapixel cameras capture more detail, even though my website images are mainly 1,200 pixels on the longest side, my Nikon D810 (36.3 MP) images are far bigger in terms of memory than my old D700 (12.1 MP) or D300 (12.3 MP) cameras.

All the images you see on this site look much better on my computer. It’s really frustrating, but a fact of posting images online.

3 crops of couple photo show how cropping photos reduces megapixels

Years ago I was watching a parade with my folks and quickly grabbed this shot with my D300 (12.3 megapixel camera) as they turned around to laugh at my joke. I didn’t have the time to compose it properly, so I straightened it up in post and then cropped tighter for better composition.

This impacted the image resolution:

1st photo: 2848 x 4288 = 12,212,224. Divide by 1 million = 12.2 megapixels

2nd photo: 2647 x 3985 = 10,548,295. Divide by 1 million = 10.5 megapixels

3rd photo: 2276 x 3426 = 7,797,576. Divide by 1 million = 7.8 megapixels

How to find out photo dimensions

In the Lightroom library module you can see image dimensions in the image metadata panel on the right side of the screen. If the photo is cropped, the cropped dimension will be shown below the original photo size.

Other photo processing software, like Capture One, will also have this feature. Then all you need is a calculator to work it out.

Is 16 or 20 camera megapixels better?

By now you should know the answer to this common camera megapixel question, but just to be clear…

You’re fine with either 16 or 20 camera megapixels, unless:

  • You’re photographing to print your images large (by large I mean a lot bigger than 40 inches x 20 inches)
  • Or you consistently crop in closely on a small part of your image (in which case, investing in a quality lens with a longer focal length would be a much better use of your money than a larger megapixel camera).

Over the years I’ve photographed hundreds of weddings and thousands of portraits on the above three DSLR cameras. Plus, I’ve printed highly quality albums and large wall art from all three cameras and you wouldn’t know which camera was used when looking at the final image.

Camera megapixels conclusion

Don’t base your camera buying decision on megapixels. Instead, look at build quality, dynamic range, frame rate, low light capacity, ergonomics, menu layout etc etc.

In other words, look at everything else before thinking about the megapixels.

To be honest, I see the huge pixel count of the next camera I want (mirrorless) as a negative. Instead of the Nikon Z7 II with 45.7 megapixels, I might opt for the Z6 II with 24.5 megapixels. I just don’t want all those high resolution image pixels clogging up my hard drive and slowing me down.

Leave a comment

If you have any questions about camera megapixels, let us know in the comments.

Also, I love good news, so if my camera megapixel tips have helped you, share that too.

4 thoughts on “How important are camera megapixels (print & post images online)”

  1. Hi
    If for viewing 720p / 1080p is required than how to resize image in 720p
    Thanks a lot for the above megapixel information


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