Amid all the fancy terminologies used by the camera manufacturers, one thing is clear, pixels and megapixels do matter for your photography. However, the importance of these terms depends on the objective of clicking photographs. Presently, it is widely adopted that the more megapixels your camera has, the better it is for use. Moreover, the camera manufacturing units have been advertising their products, making megapixels the USP. Well, if you observe the process of pixels working for your photos, you might find some interesting facts that have never been unveiled. Before that, lets understand a few basic terms in the easiest possible way.
What Is A Pixel?
Pixel is an atom of the image you’ve taken. Just like every object is made up of zillions of atoms, a pixel is the smallest unit of an image taken. In other words, pixel is the smallest unit recognized by your camera while clicking a photograph. The word pixel is inspired by the term “picture element”, which is the basic element in any programmable color on a computer. A pixel doesn’t contain a specific size of its own, it is decided by the resolution set by the user.
Now that you understand pixel, a megapixel is nothing but one million pixels. It is a result of the multiplication of the vertical and horizontal pixels of a digital image. In other words, if a camera is empowered to generate an image that is rich by 8280 pixels horizontally and 5520 pixels vertically, that is going to be a (8280 x 5520 = 45,705,600) 45.7 megapixel camera. Hope it clarifies the science behind all the hype around megapixels in cameras.
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How Is the Image Quality Measured?
The term ‘resolution’ is used to describe the quality of a digital image. Resolution has different parameters to evaluate at different work equipment’s. If you’re analyzing an image on a monitor, the resolution of that image would be on a PPI (Pixels Per Inch) basis. Whereas, printers use the DPI (Dots Per Inch) as a measurer for image. Altogether, there’s not much of a difference when it comes to evaluate the quality of picture, what matters is the medium on which you’re accessing that image.
When you take a picture, you’re also considerate about the sharpness. The sharpness of an image depends on the resolution on a specific size of the monitor. You can experience a better sharpness with the same pixel resolution on a smaller monitor. The science of sharpness is based on the scattered pixels on a wider screen. For instance, if you’re moving from an 800×600 to 1024×768, it increases the total pixels by 306,432. These extra pixels must be merged to the screen with the same amount of text or images, which makes it appear smaller.
When we talk about the image quality, you must know that almost every computer monitor contains a standard resolution. This makes a small 1080p monitor have more pixels per inch than a bigger 1080p monitor as they have same number of pixels (1920 x 1080). However, the most popular 4K monitor contains almost double the number of pixels on the similar 1080p sized monitor. It means, the same image displayed on different monitors is going to appear in different sizes with different PPI based on the pixel density per monitor.
How Many Megapixels Are Needed To Create A Billboard?
The short answer to this question is – the minimum. The real game in billboard’s is not played by the pixels or high-resolution, but the distance. When it comes to printing a billboard, what really matters is the DPI instead PPI. DPI or dots per inch represent the resolution of a printer that squirts out millions of microscopic drops (dots) of ink to form a pixel. It is important to know that most of the printers have only four colors i.e. magenta, yellow, cyan and black. However, the printers are smart enough to generate millions of colors using these four.
When it comes to printing a billboard, the drops (dots) per inch remain constant whether it is a high or a low-resolution image. It means, no matter how great the camera was while snapping, the printer would use almost the same DPI resolution to print it. Although, there are some expensive printers available in the market that are capable of printing at over 2500 DPI however, when you’re printing a billboard, even a less than 300 DPI printer works miraculously.
The actual science behind the fact that you don’t need a high-end printer to create billboard is the distance between the human eye and the billboard. A human eye is capable of resolving a limited amount of resolution based on the viewing distance. You can refer to this equation that explains the PPI to human eye i.e. 2/ (distance in inches × 0.000291).
If you wish to know the maximum resolution your eye could see at a distance of two feet (24 inches), it comes up to 2/ (24 × 0.000291) = 286 PPI. it means, at ten feet, you just need approximately 60 PPI. The human eye resolving power decreases with the distance and the same science is applied while creating billboards. Had it been fine art or ultra-high-resolution photos, they are intended to be seen closely and require the best resolution printers. However, billboards are designed to be seen from an average distance ranging from 500 ft. to 2500 ft. This is the range where a human eye cannot resolve to its maximum and even a 2 megapixel camera is good enough to shoot a picture for billboard.
Altogether, if you’re looking to shoot a snap for billboard, you definitely don’t need a high resolution or big megapixel camera as it would be viewed from a good distance. However, there are some hoardings printed that are designed to be placed in malls and shopping complexes, and are intended to be viewed closely. If you’re going for any of these, you can certainly use your DSLR cameras. So, if you’re not a professional artist whose photos are exhibited to be looked closely, you certainly don’t need to pay the hefty amount for all the extra “megapixels”.To clear it up, if you’re at a viewing distance of 2500 ft. with approximately 16 square inches per pixel (based on the size of the billboard), it comes up to only 6,048 pixels i.e. 0.006 megapixel. If you go too near to a billboard, i.e. 650 ft., it comes to 0.009 megapixel, it means that the Nikon D850 offers 472 times more resolution than required.
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