I’ve heard about megapixels being the amount of pixels in millions that a camera can take but I don’t understand how a Canon EOS R6 II can take better photos zoomed in than an iPhone 15 PM with optical zoom despite having a lower megapixel count.
I don’t get how a megapixel count correlates to the resolution, and how significant it is to the quality of the image.
In: Technology
The number of megapixels refers to the number of sensor elements in the camera. There are separate sensor elements for red, green, and blue light. Commonly you have twice the number of green elements compared to red and blue because we humans are better at telling green apart. Those side-by-side elements are combined mathematically to predict the color of light at all sensor element location.
The size of the sensor and the size of the lense determine how much light can be in each sensor element. Larger elements will collect more light. More collected light means the noise from the electronics has less of an effect on the readout value. So there what you get out of the iPhone sensor is less accurate than the Canon EOS R6 II
A large lens with more elements can be made to bend the light with less error than the small plans of an iPhone.
Light defects when it passes through a small hole, the smaller the hole the more it detracts, A lens is like a hole so a larger lens will protect the lens more accurately onto the sensor. This is a fundamental limit of physics.
That the lens difference is huge is clear but the sensor difference is huge is not as clear. The iPhone 15 Pro Max has a 1/1.28 (9.8×7.3mm) sensor compared to the full 35mm sensor that measures 36x 24 mm Look at [https://en.wikipedia.org/wiki/Image_sensor_format#/media/File:Sensor_sizes_overlaid_inside.svg](https://en.wikipedia.org/wiki/Image_sensor_format#/media/File:Sensor_sizes_overlaid_inside.svg) the iPhone has the smallest square and the Cannon the largest square. The area of the Cannon sensor is 12 times larger.
It is in the lower light conditions that a larger sensor has the main advantages, A high magnification lens has the practical result of reducing light levels,
If you look at the number of pixels the iPhone does have 48MP for the wide-angle camera but only 12 MP for the telephoto sensor. The cannon at 20.1 MP has the higher pixel count.
There is no optical zoom on the iPhone there is a fixed telephoto lens that is equivalent to a 120mm lens at full frame. Magnification is not zoom, zoom is when a lens can change the magnification.
The cannon camera can have lenses a lot more magnification. Telephoto lenses that are zoom lenses are common with max focal lengths of 200, 300, 400 and 500 mm. There are lenses with even longer focal lengths but they get extremely large and expensive. The result is a image that can have optical magnification on the cannon might need digital magnification on the iPhone.
The megapixel count will determine the resolution of an image, there is alos the aspect ratio of the sensor that matters. But the megapixel count will often not matter unless you zoom in on the image digitally. A typical computer screen is 1080×1920 = 2 megapixels, this means the computer needs to reduce the resolution of the image to 2 megapixels before it is displayed. The display contains a red, green, and blue subpixel so if you count it as a camera sensor it is 6 megapixels with an equal amount of each color or 8 with twice the amount of green. This mean something below a 10-megapixel camera has the same number of sensor element as a display have subpixels. If you magnify the image on the computer and only look at a part of it, print it at high resolution or use a higher resolution display you need more pixels.
The point is that more pixels than are needed on the output device might be less useful then you expect. More camera megapixels are more of a marketing advantage. At the same sensor size, more pixels mean less light per pixel. So fewer pixels can be better in the right condition, I suspect that is why the telephoto sensor in the iPhone has fewer pixels than the wide-angle sensor, you get less light, and diffraction limits come into play. A 48MP sensor on that tiny lens like produces a worse image
So for photos in direct sunlight of stuff that is close to the camera, you can have quite similar results on the Cannon camera and the iPhone, But if you look at stuff farther away or in lower light conditions the Cannon has a clear advantage.
Latest Answers