13mp: Is it necessary for smartphone optics?

Yesterday, as everyone here should have heard, Samsung took the wraps off of the Galaxy S4. Since then, this forum has gone ablaze with people arguing about build quality, software features, and generally whether the S4 is even a big upgrade. Even though I have a few reservations on the S4, overall it's a fine upgrade, regardless if it looks physically similar to the S3.

One thing that I have noticed about Samsung, and this may be my biggest reservation on their recent mobile products, is that they seem to think bigger is better. Every year Samsung's flagship phones have increased in size and it's hard to figure out why. Sure, bigger screens may arguably make the experience more immersive and, in some cases, make the device easier to operate (clicking on small links, typing on roomier keyboards, etc). However, I've been thinking about this for a while and in Samsung's case I may have the answer. From an engineering perspective, it's easier to manufacturer a bigger device than a smaller one while holding the hardware constant. Think about it. Wouldn't it be much harder to fit that octa-core and 1080p super amoled display into a 4.3 inch chassis? Issues like heat dissipation from the battery and various components become much harder to solve. Will next year's Galaxy S5 have a 5.2 inch screen? What about that rumored 6.3 inch Note 3 rumored for this year? I just don't have faith that Samsung knows when to stop because they are playing a numbers game.

Octa-core processor, 13mp camera, bigger battery, bigger screen, and the list goes on. There's absolutely no reason a phone needs an octa-core processor, it's purely a marketing gimmick, similar in fashion to the Tegra companion core thing from a while back. When it was first announced I vividly remember tech commenters blindly praising the thing like it was a breakthrough, but look what happened with that. I wish people wouldn't fall for marketing and big numbers so easily.

As a photographer and undergrad physics student, however, I want to touch upon the camera optics. I'm sure everyone here has read about HTC's new UltraPixel camera on the One. First off, I was somewhat confused and disappointed to see so many people blindly bash the new 4mp sensor without having a basic understanding of how light gathering works on a camera sensor. Smartphone camera sensors are pretty damn small and regardless of what marketing buzz words you hear on TV, there's no way to get around that. You can have a 20mp sensor on a next generation smartphone and I GUARANTEE the image quality won't seem 20mp better. Why? Because when you increase the number of pixels on a smartphone sensor, you're making each pixel physically smaller. Smaller pixels = less light gathering = more noise = less detail. In camera optics, whether you have a full-frame DSLR or a smartphone, everything obeys the same laws of physics. More megapixels does not mean you're getting a better image! In fact, it almost never means that.

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Low light performance on the Galaxy S4 will either be extremely noisy due to in-camera processing, or way too dark because it can't gather enough light. Additionally, there's a big possibility it may be worse in low light than the S3 and Note 2! Again, there's no getting around physics. Unless Samsung has crafted some magical software that can remove noise while keeping detail mostly in tact AND brightening the image, the S4 will be worse in low light than previous gen phones. People need to start realizing this because adding more megapixels to a camera sensor is absolutely the wrong direction to go.

Going back to the HTC One: because the camera sensor has less pixels on it, each pixel is physically larger in size and gathers more light. Quantum physics tells us that photons of light are small bundles of data. Since the HTC One can gather more light, it will actually resolve more detail. In low light it won't even be a comparison - the HTC One will utterly destroy any 13mp sensor out. The only site to really bash the HTC One's camera is The Verge ironically; everyone else is praising it and it's definitely deserved. I'd rather put my faith in physics than the opinion of a single person. Not to mention the HTC One has optical image stabilization which will be a godsend in lowlight. People are praising the S4 for 13mp but why? Do you prefer quantity or quality?

Check out these camera comparisons. The One manages highlights very well and has fairly accurate colors. I'm loving what HTC did with the flash. The flash on my iPhone 5 nearly ruins the picture when I use it.

http://www.zdnet.com/camera-phone-comparison-htc-one-blackberry-z10-iphone-5-lumia-920-and-note-ii_p34-7000012594/#photo

http://gizmodo.com/5990360/htc-one-ultrapixel-camera-how-does-it-stack-up

Some good reads on Anandtech: http://www.anandtech.com/show/6777/understanding-camera-optics-smartphone-camera-trends

http://www.anandtech.com/show/6779/how-the-htc-ones-camera-bucks-the-trend-in-smartphone-imaging

To sum it all up, don't go around blindly praising higher numbers and marketing gimmicks. Give credit where it's due. Let's turn this into an educated discussion and not a pathetic fanboy war! Thanks for reading.