In the world of digital cameras and smartphones, marketers use the term “megapixels” frequently to describe the quality of the images produced by these devices. But what are megapixels exactly, and do they really matter? Megapixels refer to the number of individual pixels that make up an image. The more megapixels, the more detail and resolution the image can have. However, simply having more megapixels doesn’t necessarily mean better image quality. In this article, we’ll dive deeper into the world of megapixels and explore their role in determining the quality of digital images.
Megapixels Video Tutorial
In just 90 seconds, we unravel the mystery behind megapixels to help you determine whether or not you need more of them.
What Are Megapixels? A Brief Definition
Megapixels (MP), which translates to “one million pixels,” dictate how much detail your camera’s sensor can capture. In digital photography, the number of megapixels in an image refers to the total number of pixels that make up the image. To determine this number, multiply the number of pixels in the width of the image by the number of pixels in the height of the image.
The higher the megapixel number, the more potential detail can be captured within an image.
How Do Megapixels Affect Image Quality?
Generally speaking, the more megapixels an image has, the higher its resolution and level of detail. This is because a higher number of pixels means that the camera is capable of capturing more information.
However, it’s important to note that simply having more megapixels doesn’t necessarily mean that the image will be higher quality. Other factors like lens quality, sensor size, color resolution, dynamic range, and more play a role in determining image quality.
Additionally, the level of detail that can be captured by a high-megapixel camera may not be noticeable unless the image is viewed at a large size. For example, the image below was shot with a 12 megapixel Nikon D700 and the image quality is stunning. One can really see the detail when viewing the image online, as a slideshow, or in 10-20″ prints. For these viewing conditions, the 12MP sensor provides more than enough resolution and allows for a small amount of cropping.
When Does Size Matter?
While it’s true that other factors beyond megapixels can compensate for lower megapixel counts, there are situations in which high megapixel counts are necessary.  For example, when sent to print, a 20 MP file can yield an 18″ wide print without any upscaling in Photoshop or other photo editing software. Yet, how often do you print 12″x18″ photographs? For most consumers, the answer is “not often.”
How Many Megapixels Do You Need for Online Display?
Most images end up online, usually on social media. However, online and social media usage rarely exceeds 2MP. That means the other 18 MP you paid for never really get seen. Even a 4K display can only present 8 MP worth of your photograph.
How Megapixels Affect Cropping
When an image is straightened or cropped in post production, resolution is lost. So, if you crop your images heavily, a higher megapixel count will give you more flexibility.
This also applies if you display an image photographed in landscape orientation in a vertical (or portrait orientation) format. For example, to place a landscape orientated photo in a vertical slideshow format, such as an Instagram reel, a higher megapixel count will work better.
Who Needs More Megapixels?
Do we all need $50k cameras that produce 100 MP images? Not exactly. Most cameras feature 20-40 MP these days, and yet most photographers don’t use their camera to its potential. A camera with a 20 MP sensor will only yield 20 MP worth of detail when it is used by a proficient photographer. The means the photographer must understand how to maximize detail and resolution using lighting and other means.
In other words, highly proficient photographers that are seeking cameras that can print directly to large format with incredible detail reproduction or provide extreme cropping capabilities can utilize cameras with 30, 50, or even 100 MP.
For everyone else, purchasing a 50 MP camera is like buying a 600-horsepower car to drive 30 mph.
When Do Megapixels Matter?
Sheer resolution becomes a factor when enlarging and performing extreme crops. For example, because detail is more visible when blowing a photo up to a 20×30 inch canvas versus a 4×6 inch print, having a higher megapixel resolution is important in bringing out more crisp details in your enlargements. Also, if you happen to have a 40 megapixel image, and need to crop 80% of the image, you will still have plenty of detail left for that enlargement.
The image above is shot with the 36 megapixel Nikon D800. With this much resolution, there is plenty of room to crop the image and still produce high-quality photos. The example below is a 100% crop sample from the previous image, and as you can see we still have enough detail left to use for either posting on the web or even printing.
Similarly, if you are an advertising or fashion photographer then ultra high resolution sensors can mean a lot more flexibility in production. Just imagine an editorial photographer taking a single full length portrait, and then being able to create printable crops focusing on the subjects facial expression, dress, wrist, neck jewelry and shoes, all from one shot!
Compared to the Nikon D800, the Phase One medium format camera has more than twice the megapixels, resulting in an incredible amount of detail saved even after extreme crops.
The image above is taken with a staggering 80 megapixel digital back sensor. Even at just 50% crop, we can still get beautiful details of the model’s face, clothes, and jewelry with enough resolution for a full-page spread publication!
The Wild Card: Re-Sizing a High-Res Image
A third megapixel myth needs busting before we wrap up, and that has to do with down-sizing your high-res images. Â Many people argue that down-sizing your high-res images is not as good as if you simply had a sensor with lower megapixels in the first place. Â However if you compare image detail and dynamic range, this is not true.
For example, if we compare images from the 16 MP Nikon D4 and the 36 MP D800, with the D800 image re-sized down to 16 MP, we’ll see far more detail in the D800 16 megapixel image.
The bigger debate has to do with ISO performance and re-sizing high-res images. If you want the absolute best low-light performance, should you use a 16 MP sensor or a 36 MP sensor? Â Without getting too geeky, suffice it to say that by re-sizing a high-res image, you do indeed gain a considerable amount of low-light performance. At least, you get better noise reduction performance.
Can Too Many Megapixels Actually Be Bad?
Additionally, if you shoot a high-volume of images like for a wedding or action sports, then you may not want 4,000 images at 40 megapixels per photo shoot. When shooting at that rate, it won’t take long to run out of hard drive space.
For example, a studio that shoots 150 weddings per year may produce over a million RAW images per year. At 40-50+ megabytes per image, that comes out to 25-30 Terabytes of storage! Â Of course, the average shooter may only have to buy one or two extra memory cards and hard drives. Storage needs will vary based on your personal workflow volume.
Another consideration is editing speed. Â Let’s consider again the wedding photographer who generates roughly 3,000-5,000 images per wedding. Â Even if the difference in editing time equates to a few seconds per image, the workload can increase significantly. If you double or triple the megapixel count, editing time can increase by quite a few hours per week.
Conclusion
In conclusion, while megapixels can act as a helpful indicator of image quality, they represent only one of many factors that determine the quality of a digital image. Other factors, such as lens quality and sensor size, also play a significant role in determining image quality. Whether or not megapixels matter ultimately depends on your intended use for your images. By considering your needs and how you plan to use your images, you can determine the appropriate level of megapixels for your photography.
