how can smartphones have 108MP cameras, yet conventional cameras achieve better results with apparently less MP

Question

I get that more MP is better ends up being pure marketing. However I don’t understand why all cameras don’t bring 108 MP sensors or whatever. I’m confused.

In: 16

Answer 1

Dedicated cameras with full-frame sensors are much larger than a cell phone sensor (remember something like an iPhone Pro has 3 sensors on the back, 1 per lens).

Smaller sensor means less light hitting it, which means for the same shutter speed (capture time) to get the same brightness you need to increase the ISO (noise). The main way to increase detail such that the high noise isn’t so bad looking, besides smoothing, is to increase the megapixel count (so the noise artifacts are smaller, and of course higher detail).

So, even though ~12MP is enough for an 8×10 print if you don’t crop, a cell phone needs much more than 12MP or else the image would be noisy or heavily smoothed.

____

My Sony A7RIII has a 42.4MP camera with a full-frame (35.9 x 24 mm) sensor, which is an area of 861.6mm^2, so each MP has an area of **~20mm^2**.

My iPhone 15 Pro Max’s main camera is 48MP with a sensor size of 9.8 x 7.3mm (from what I could find), which is an area of 71.54mm^2, so each MP has an area of **~1.5mm^2**, which is <1/13^th the size of my Sony camera.

_____

As for why professional cameras rarely go over ~60MP, it’s because their processors aren’t fast enough. The reason the cameras most YouTubers use is only a 12MP Sony (A7S series) and not the higher megapixel count A7R series is that these cameras have rolling shutter and other issues which make the video not look as good. High MP count in RAW would also lead to very slow burst mode. You have stacked sensors which do a faster job, but they are reserved for the higher end models and even then it doesn’t fully solve the issue. The processors inside are also doing tons of stabilization and auto-focus (new ones incorporate AI auto-focus), so they aren’t reserved solely for faster capture time. This also is why they have a rolling shutter and only super expensive movie cameras have a global shutter (where the entire sensor is read at once, versus line by line).