It is a truth universally acknowledged that Sony makes the best image sensors, particularly for the cameras in smartphones. This is the reason why almost every phone that dreams of competing with cameras, even the full-fat DSLR cameras, uses a Sony image sensor. This is true for the iPhone, including the latest iPhone 7 and the iPhone 7 Plus. It is true for the Nexus phones. It's true for Samsung Galaxy S7 and the Galaxy Note 7. It is true for the HTC 10. And it is, on paper, also true for the phones like the Xperia XZ, a high-end Sony phoned launched in India on Thursday.

But then there is also the fact that Sony doesn't use the best image sensors it makes in its own phones. Instead, these sensors go into, for example, devices like the Nexus 6P and HTC 10. And that is all very strange because Sony surely has grand ambitions with its Xperia phones and often pitches them as the top shooters in the market. For the Xperia XZ too, it makes the claim that this is the Android phone with the best rear camera. And yet, we see that the company doesn't use the best image sensor it has for the Xperia XZ.



The better image sensors



When it comes to camera hardware, there are several parts. And Sony is a master in making all these parts, or at least have enough expertise to ensure that the rear camera in its phones is top notch. After all, Sony is the only phone maker that also is a major player in the camera market. Samsung too was a camera powerhouse but those days are gone. And on the other hand, there is also Panasonic that makes some amazing cameras but its mobile division is seemingly different and totally separate from the camera team.

Sony is the only company that is a major player in the high-end phone market as well as a big player in high-end camera market. Its expertise in camera hardware is such that its image sensors now power almost whole of Nikon's DSLR camera range.

When it comes to phone cameras, and the image sensor inside them, Sony makes tens of sensors. Of these the largest sensors are IMX 377, IMX 388, IMX 300, IMX 338 and IMX 260. In the latest Xperia -- the Xperia XZ -- Sony has used the IMX 300. Now that should be the good news, right? No. The reason why large image sensors are considered better is because they tend to have large pixels in general. And large pixels mean that each pixel theoretically captures more light and data.

Also Read: Sony Xperia XZ with 23MP camera launched at Rs 51,990

Sony is the only company that is a major player in the high-end phone market as well as a big player in high-end camera market. Its image sensors now power almost whole of Nikon's DSLR camera range.

But the pixel size is not just dependent on the size of the image sensor. It is actually determined by the number of pixels an image sensor has. So even if the IMX 300 is a large sensor measuring over 7.8mm diagonally, because it has a total of 25 megapixels, these pixels are really small at 1.1um. In comparison, the IMX 377, which has been used inside HTC 10, has a comparable size but only 12 megapixels. The result is that each pixel in the IMX 377 has a size of 1.55um, almost 50 per cent bigger than the pixels in IMX 300.

This is the reason why the top DSLR cameras, which are tuned for superb performance in low light, have lower megapixel count but big sensor.

The bigger pixels capture more light, more data, better colours, better shadows, better highlights, better contrast. True, it is a tradeoff. More megapixels on an image sensor do have some advantage. But once you have moved beyond 6 to 8 megapixels, this advantage disappears, particularly when you consider that most images nowadays are used on the web in small sizes.

But the advantages that bigger pixels offer continue to matter. This is the reason why Apple stuck with its 8-megapixel sensor for years before moving to 12-megapixel camera in the iPhone 6S. This is also the reason why companies like HTC, Xiaomi, Samsung, Google and Huawei use 12-megapixel cameras in their phones. But Sony doesn't use the IMX 377, arguably the best image sensor for a phone it has made, in its own phone.



Strange Sony



This is very strange actually. There are many other phone companies that are particularly impressive at making a part. And all of them use the best parts in their own phones.

Samsung, for example, is the leader in technology of AMOLED screens. It makes the best AMOLED screens. And it sells those screens to a number of phone makers. Yet, it always reserves the best AMOLED screens that it makes for its high-end Galaxy S and Galaxy Note devices. It calls them SuperAMOLED screens. For example, the screen in the Galaxy S7 is the best in its class. No other phone has the same screen, possibly because Samsung is not willing to part with it. It doesn't want competitors to use the best screens that it makes.

The same is true for LG, which makes some awesome batteries. But just like Samsung, it seemingly reserves the best batteries for its own phones. Apple makes the fastest mobile processors. But again those are limited to Apple's own use. Samsung too makes some good Exynos processor, which are available to other phone makers but they are also used in the top Samsung phones.

Sony seems like an anomaly. Now, surely there is a business angle to it. If it has some parts for which other companies are willing to pay the price and premium, why not sell them. That is a sound business decision. But unlike other companies that often use the best parts in their own premium products, even if these parts are also available to the competitors, Sony doesn't. Now whether this is a move to keep the cost low or if there is some others factors at play, I don't know. But the way it looks like, this strange policy does seem to be hurting Sony and its phones in the market. The devices with a camera that has tons of pixels look good on paper but we have seen it again and again that devices that have bigger pixels -- the Galaxy S7, the Nexus 6P -- actually deliver better results.

Sony seems like an anomaly. Unlike other companies that often use the best parts in their own premium products, even if these parts are also available to the competitors, Sony doesn't.