2 minutes should be too long, so please watch it, I'm not working for Nokia, if that's what you're thinking but they advertise their camera tech a lot and they just so happened to release this video~ It will seriously help later on, trust me. =)
If you're done watching the video, keep it open so you can easily refer to it should you need to, and I'll try to explain as much as I know about each feature they show you!
Starting with.... THE FLASH
Just to satiate those who thought of this when I mentioned flash (you're welcome =D)
Okay, I'm sure if you are one to compare specs or the company just likes promoting their product, you've probably heard of Xenon flash, and LED flash and also with the new iPhone out, Dual LED?
That's exactly what they showed you at the start of the video when the flash went off before capturing the picture. At just around 0.03 secs to be exact.
The phone in the video is equipped with a Xenon Flash, whilst other phone manufacturers would usually opt for the LED flash. Just to give you a heads up, Xenon Flash is better, but why? Let's get to it~
LED Flash speaks for itself, it's an LED (Light Emitting Diode) that's supposed to provide some sort of lighting when light is absent. The thing is, LED's don't emit light that travel very far. A Xenon flash is capable of emitting light 3 times farther than the regular LED. And that's just one of its upsides, the light emitted is also stronger so it can illuminate the object better and the fact it travels farther means you get more even lighting to a picture than something the LED flash would cook up.This also means more noise can be reduced and this all translates to a better photo overall.
Here's some photos to demonstrate the difference:
LED Flash
Xenon Flash
photos are taken from black phoebe, check it out here
Now dual LED flash is something different. Dual LED flash fires off a flash and then another following the previous flash. This translates to better lighting overall but at a cost of colour. The flash can often wash out the colours because of the immense light it releases. And it doesn't really help with providing even lighting because it is still LEDs so the light doesn't really travel farther.
Apple has introduced a Dual LED flash but this time, they've put two different LEDs, one white and one amber to prevent the washed out colours I've talked about before, does it really do well? Well, honestly I still don't know yet so we'll see.
Now don't go smashing every camera that doesn't provide a Xenon flash just yet, first of all, manufacturers don't opt for it because its more expensive, takes up more space (the phone would have to be thicker) and also it uses more battery power. There are also other ways to help a camera perform in low-light conditions.
Shutter and Aperture
MOVING ON! After the flash goes off and the light bounces off and moves towards the phone, you see, the rays entering the camera, right? When it is about to enter the lens, you see it opening, that's the shutter. The shutter limits the amount of light that enters the lens to generate the image. So often when you want to capture low light photos, the camera often prolongs how long the shutter remains open so more light can enter.
Another part worth noting is how big the hole or the more fancy term, "aperture" is, the bigger the aperture, the more light can be captured without affecting how long the shutter remains open. This also allows for the pictures generated to have a greater depth of field. A good example would be, the new iPhone 5S, which has a greater aperture than the previous iPhones. So, to cut it short, the smaller the aperture value, the more light can be captured and your pictures will have a greater depth of field. The iPhone 5 has an aperture value of f/2.4 whereas the new one has the aperture value of f/2.2. See, the smaller the number, the bigger the size of the aperture. Like I said, there are other ways to get good photos in low light and it involves these elements, hardware and software, working together, harmoniously, courtesy of Jony Ive (hatechu)
Image Stabilization
Following the video, after that, the light travels through a series of lens and then there's like a bearing moving around, right? Well, that bearing right there, is used to stabilize the lens because when it comes to taking photos, our hands are our worse enemy. They shake and move around and make it hard for you to produce a better picture. Ever so often when taking photos, they shutter speed is fast enough that your hand moving will not effect the quality of the picture taken. Much like how when they want to freeze a fast moving object in a picture, they use a very high shutter speed to capture the image, in the camera's point of view, at the point of time when the picture is taken, your hand is as though it was frozen in place.
But I did mention that when in low-light or when its dark, the shutter has to remain open longer to get more light. But doing this opens the picture to shake and to cut things short, the image turns out blurry. To counter this, you can use a tripod but carrying a tripod everywhere isn't the easiest of tasks to carry. Well, manufacturers have introduced Image Stabilization. The two common ones are DIS (Digital Image Stabilization) and OIS (Optical Image Stabilization) which is also sometimes known as Mechanical Image Stabilization.
DIS is done completely through programming, hence the name. By reducing the actual Field of View captured by the camera, they reduce the shake affecting the camera. Other methods also include increasing the sensitivity of the sensor (we'll get to that later) at the time when the shutter is closed and etcetra. However, this is not the best of image stabilization technology and sometimes can be buggy. Some also don't like the fact is reduces the camera's field of view.
This is where OIS comes in. Optical Image Stabilization is where the lens is physically mounted on a motor that will move the lens in the opposite direction the camera shakes to, leading to a better image. And because it does this much more effectively than DIS, having OIS in a camera also means better low-light performance. DIS is usually used because its cheap and OIS often makes the camera more bulky.
Sensor
Letting the video move once more, you'll see the light passing through a series of lens and then the light hits like a panel that has tiny squares on it, igniting each square the rays hit right? Well, what you're looking at there is the camera sensor. Notable keywords you should have in mind are CMOS, BSI, BI, and if you like more fancy names, Exmor R, Exmor RS. Those are all camera sensors. The typical camera sensor would be a CMOS Sensor, simply because its smaller and that right there has led to cameras being mounted on smartphones. So almost all smartphones use CMOS Sensors. Now how about BSI? Well, first of all, BSI and BI are the same thing, they stand for Backside Illuminated and Back Illuminated respectively. Are they different than CMOS sensors? They are CMOS sensors, to begin with, its just that BSI Sensors have their circuitry moved around a bit. To actually show why this is relevant, I'll have to explain how CMOS sensors work. (Don't worry, I'll make it short as possible)
CMOS Sensors have three layers, the first layer is are filters, Red, Blue and Green, the next layer is metal wiring and the last layer is the photodiode where light is converted into data to produce the picture. Here's the diagram.
photo is courtesy from Sony Global
Sony shifted the photodiode layer with the metal wiring, but to doing so, see the green line indicating the front side of the substrate, yes, doing so, also point the front side downwards, so now the photodiode is illuminated from the back, hence the term Backside Illuminated. This is done so that the light won't reflect off the metal wiring thus making the sensor more efficient at capturing light. With the conventional CMOS sensor, the light capturing rate would be between 30-80% but with the BSI sensor, the capture rate would be 100%.
But what does this all mean for picture quality? The cameras would be better at low-light photography, which is why in Sony's Advertisements, they would say "great pictures in any light". Also, it would better picture quality in terms of noise and color reproduction as well as depth of field and contrast. Most high end devices come with BSI sensors so now you know what that implies.
Also courtesy of Sony, this can all be found on their Sony Global Page
Exmor RS, is simply the Exmor R that has been reduced in size so that the sensor wouldn't take as much space.
Okay, that's all I would be able to explain with my understanding based on that video, the rest of the video simply explains how all that light is shown on the phone's screen.
Hopefully, now you'll be able to understand more when manufacturers market their smartphone camera technology =)
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