How could they deliver an industry leading imaging experience within the sleek dimensions of the Nokia Lumia 720? We spoke to Juha Alakarhu (@jalakarhu), Nokia’s head of imaging technologies, to find out.
The best camera possible
“There are many factors that influence camera performance; it’s all about finding the right balance of these factors.” says Juha Alakarhu, Nokia’s head of imaging technologies.
“We simply wanted to create the best possible image quality with this product. Everything else was secondary. It’s what you can capture with the camera that matters rather than the technical parameters.”
As a result of this steadfast approach, the Nokia Lumia 720 has an outstanding imaging experience for a midrange smartphone.
Seeing light through the dark
“So, as we had free hands to decide the technical parameters, we first created several concept designs and simulated their performance. We actually considered different sensor sizes, pixel sizes, and resolutions from 3 to 12 megapixels. Going too high resolution could lead to reduced aperture size (the hole that lets in the light). On the other hand, we didn’t want to go too low either, given the physical limitations set by Bayer sampling and Nyqvist theorem. (*)” In the end, Juha’s team found that the 6.7 megapixel sensor was the perfect sweet spot for this sleek-design camera.
The key innovation has been increasing the aperture to f/1.9. This is the biggest aperture on any Nokia smartphone, and it’s no surprise that the Lumia 720 captures excellent images in low light conditions. This is a problem, of course, that Nokia has already solved before.
“We are utilising the same know how that we developed in the Lumia 920 so the image sensor technology is similar. It has the latest back illuminated technology and it also has the true 16:9 mode that no other handset manufacturer but Nokia has,” says Juha.
“Great hardware alone doesn’t make a great camera. We also need great imaging algorithms. We have very clever noise reduction and sharpening algorithms. We spent a huge amount of time perfecting them to keep the images as natural as possible in all conditions.”
Look to the front
The Nokia Lumia 720 was developed in, and to a large degree inspired by, China.
This Chinese influence also spread to Juha’s imaging team, where the local enthusiasm for taking self-portraits has resulted in the best front facing camera that Nokia has ever made.
“I believe that this is the only front facing camera in the world that is using four physical lenses,” says Juha. “This is very rare because most front facing cameras only use two or maybe three lenses. Four enables us to get the best possible sharpness.”
In addition, the front facing camera has an aperture size of f/2.4 and the sensor is also back illuminated. The wide-angle lens means that you won’t just be able to take portraits of yourself but there will also be room for a friend too!
See the quality
“I would recommend anybody to use the Lumia 720’s camera, take images in any possible conditions, compare it to any camera that you have and you will see the quality in the Lumia 720.’
Here are some great shots to prove it.
(*) Bayer color filter arrangement is used in almost all digital cameras. With Bayer color filters, half of the pixels sense green light, 25% sense red, and 25% sense blue light.
In essence, Nyquist–Shannon sampling theorem says that you have to sample input data with two times higher frequency than maximum output frequency.
