First, let us understand megapixels:
- A 480p image has a resolution of 640 x 480, and the multiplication 640*480 = 307,200 = 0.3 MP
- A HD image/video has a resolution of 1920 x 1080, and the multiplication 1920*1080 = 2,073,600 = 2 MP
- A 4K image/video has a resolution of 4096 x 2160, and the multiplication 4096*2160 = 8,847,360 = 8.8 MP
In fact, what limits the quality of the picture in a camera or phone is the processing power - huge amounts of CPU grunt is required to capture 8,847,360 points of light accurately for 30 times in second (while shooting a 4K 30 fps video).
The biggest factor that goes into shooting great quality images is the size of the sensor. A full frame dSLR camera has a 36 mm x 24 mm sensor size, while the iPhone 5S has a 4.8 mm x 3.6 mm sensor. By reducing the size of the sensor, you are cramming the same number of pixels into a smaller area, hence reducing the quantity of light falling on a pixel. This is the exact reason why a 16 MP full frame camera captures better quality pictures than the 16 MP camera on your phone.
In order to cram so many pixels without distorting the colour of light falling into every ‘pixel’ unit on the sensor, smartphone companies are using newer technologies like Deep Trench Isolation to isolate each pixel from another.
Many companies have even taken to reduce the number of megapixels of the sensor to produce better quality images. For example, the Samsung Galaxy S6 has a 16 MP camera while the Galaxy S7 has only a 12 MP camera. However, the images/video from the S7 is of better quality from that of the S6. Perhaps now you realise why Apple stuck with 8 MP cameras until the iPhone 6 and only expanded it to 12 MP on the iPhone 6S because of the 8.8 MP requirement for capturing 4K video.
The truth is that you will most likely never even view these images in their full resolution. Smartphone screens are usually HD quality (that’s just 2 MP), so the 4K content you are capturing is scaled down to be viewed on your device.
There is no point in choosing a phone or a camera based on the megapixel count, as long as it is a reasonable number. Instead, consider these factors:
- Is the image/video quality actually pleasing to the eyes? Look for sample images taken from the camera.
- Read user reviews of cameras/phones and don’t just go by the specifications.
- Consider other factors that affect image quality, like aperture. Choose a phone that has a larger aperture (i.e. lower number spec). An ƒ/1.8 aperture will allow for better low-light images than an ƒ/2.2 aperture.
- Make sure there is a ‘Higher Dynamic Range’ (HDR) option, as it allows for greater contrast levels.
- Optical Image Stabilisation (OIS) and Laser Autofocus are great additions that improve camera performance and quality.
And now you know how to purchase a better camera!
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