Why are smartphone camera bumps so huge?

Regardless of whether it is the new Samsung Galaxy S21 Ultra, the iPhone 12 series from Apple or the Huawei Mate 40 Pro, the bumps in the camera body feel bigger than ever before. In fact, the phones with the largest camera bodies usually take better pictures. On the other hand, phones that were picked up did not adhere to the pecking order. While this trend seems to have a positive impact on the quality of photography, it isn’t the most aesthetically pleasing compromise and results in bulkier phones.

When it comes to high-end mobile photography, it’s impossible to escape the camera bump. But why? Let’s delve a little deeper into the inner workings of the smartphone camera to understand.

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Focal length, lenses and crop factors

Before we get into the explanation of camera bumps, we need to study some of the essential attributes and terms of all camera designs.

We’ll start with lenses and focal length. Every camera lens, from DSLRs to smartphones, focuses the incident light on the focal point known as convergence. The image sensor is located in this focal point to digitally capture your image. The focal length defines the distance from the lens to the focal point, measured in millimeters. In reality, however, complex lens layers mean that the actual length is often less than what is stated. However, the effect is the same.

Dive deeper: What is the focal length in photography?

In simple terms, the focal length defines the field of view and the “magnification” of the camera. Longer focal lengths narrow the field of view and increase the magnification. This leads to a zoom effect. You can imagine it by thinking of how changing the focal length changes the angle of view as light is refracted through a camera lens. See the picture below as an example.

It is important that the focal length also influences the perspective of the image. At longer enlargements, the separation and distinction between foreground and background objects is less visible. See the apparent distance between the trees in the picture above. Remember we will come back to this later. This nuance has been the cause of much discussion about OnePlus’ zoom capabilities in the past.

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The other equally important part of this equation is the “harvest factor”. It is often confused with the characteristics of the focal length. The cropping factor of a camera depends on the size of the image sensor. Imagine looking through the camera lens. The lens takes a picture regardless of the size of the sensor. Therefore, the final image captured by the lens is cropped depending on the size of the image sensor.

Note that a smaller image sensor has the side effect of creating a tighter crop and field of view. This creates an enlarged look for full screen images called focal length multiplication. This is one of the reasons you can find tiny image sensors that are used in smartphone telephoto cameras. However, cropping does not have the same perspective effect as a native full-screen focal length at the same magnification. The crop factor is important to understand as it plays a role in the fields of view for both zoom and wide angle cameras on smartphones.

The search for bigger sensors and longer zooms

With the concepts of focal length, magnification and crop factor, we can draw our attention to the trend towards thicker smartphone camera housings.

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The first reason for larger camera bodies is the pursuit of longer range zooms. As mentioned earlier, the focal length is a key component of a camera’s magnification. While complex lens structures can increase the effective focal length, zooming over longer distances ultimately requires a greater distance between the lens and the sensor. This requirement is the driving factor behind the use of periscope technology in zoom cameras with a very long range without a large camera shock. These extend the distance from the lens to the image sensor using mirrors to reflect light. The tendency towards longer telephoto zoom functions is almost certainly a factor in thicker camera shocks.

The second factor that causes larger camera bumps is the desire for larger image sensors. Such sensors improve light absorption and image quality. While sensor size is related to crop factor rather than focal length, there are reasons why longer focal lengths may be desirable with larger sensors.

For starters, smartphones likely want to keep the same picture frame and magnification as previous designs when they switch to a larger sensor. To keep the same crop factor with a larger sensor, a longer focal length is required. Otherwise, you will have a wider field of view which may not be desirable. This is more important in the context of multi-camera systems that require set magnifications between the ultra-wide, main and telephoto camera setups.

Continue reading: Why the size of the camera sensor is more important than more megapixels

Finally, we need to take into account the lens distortion, which is usually most noticeable around the edges of the lens. Increasing the sensor size and using a larger section of the lens can result in more distortion. This is more of a problem with small, large aperture lenses used in cell phones. See the picture below as an example.

This is where high quality lenses can help. However, it is notoriously difficult to build these for compact smartphone form factors and their very large openings. An alternative solution is to adjust the focal length. Then, thanks to the lens’s high quality sweet spot, the field of view falls closer to the center, where there is less chance of distortion. However, this in turn requires the use of a longer focal length and thus a larger camera housing.

Also consider the inverse requirements of wide angle sensors. Larger sensors or shorter focal lengths are used to expand the crop and / or enlarge the field of view. Because of this, you’ll notice a lot more distortion around the edges of your wide-angle images.

Why are the bumps in the smartphone camera so large?

While there hasn’t been a single explanation for the increase in thickness of camera bumps in recent years, there is a common theme. The trend is for smartphone camera designers to battle the laws of physics to improve camera functions and image quality.

Connected: What to Expect from Smartphone Cameras in 2021

The desire for longer range zoom capabilities and larger image sensors to fill the gap in DSLR cameras are the two biggest drivers driving the trend. It is no coincidence that smartphone cameras with industry-leading sensor sizes, zoom capabilities, and image quality tend to have larger camera shocks. While phones with more traditional camera features can maintain leaner form factors.

Not to mention the demands on larger batteries, 5G antennas, and various other technologies vying for valuable space in modern smartphones. There is simply no other option than to build thicker phones or bigger camera bumps when you want to take advantage of all of this technology.