Why a 12 MegaPixel Camera May Not be Better?
Apple just announce the new iPhone 7 with a new higher resolution camera built in. It is now a 12 MegaPixel camera at your finger tips. The problem is, more is not necessary better. There is a cost associated with the increased resolution. Unless you can justify the need for the increased resolution, you are just going to create more data, transmit more data and throwing away the data.
- Sept. 2016
I come from a long history of dealing with image processing and high resolution color capture systems. While working at IBM Research in the 1990s, our team developed one of the most advanced color capture system for museums and libraries. Our technology was deployed all over the world in renown institutions such as the Hermitage museum and the Library of Congress.
Why is more resolution not necessarily good? The simple answer is data size. The higher the resolution, the larger the file size it creates. That means more data to process, to transmit and to store. It is not only a matter of costs In terms of dollar and cents. The cost of memory storage is dropping all the time. That is the good news. However, increasing data storage and transmission has real costs in terms of bandwidth and transmission time. Why should we pay for this if the increased data is not noticeably different?
To put things in perspective, your large PC screen that sits on your desk is only 1280x1024 resolution. That is a maximum of 4 Megabytes of raw uncompressed data. In order for you to process the 12 MegaPixel image captured by the iPhone 7, you need to shrink that data by a factor of 3 just to view it. If you are looking at it on your phone, you will need to shrink it more.
The other part of the image quality consideration is the amount of signal. A CCD chip contains millions of cells that convert light signal into electrical pulses. By squeezing more pixels onto a CCD chip, you are reducing the signals from each pixel. The key to image quality is the signal to noise ratio. That is the reason you see noise in a very dark image. The signal is already small and hard to distinguish from the noise.
iPhone 6 vs. iPhone7
Image File Size
A 12 MegaPixel image will compress on average to 1.2 MB JPG file, while a 6 MegaPixel image will compress on average to only 600KB JPG.
It is said a picture is worth 1000 words. When you take a picture on the new iPhone 7, just remember, you are creating double the data. Can you see the difference?
Some Related Info
- Image Processing for the web
My tutorial on some basic image processing techniques.