When you launch your camera app from your smartphone or tablet, does the image take up the entire screen or just a portion of it? This is an important question to consider since most smartphones today use a 16:9 widescreen aspect ratio just like our HD widescreen TVs. Photography just isn’t meant for this aspect ratio and the more square 4:3 ratio has been standard for decades.
Let’s break the issue down to the hardware of the camera. Virtually every image sensor produced is made in a 4:3 or 3:2 aspect ratio. This more square shape maximizes the light captured by the round lens. A wider image sensor would miss out on collecting light on the top and bottom of the lens. But the most obvious reason is tied to money. Almost every image sensor manufacturer mass produces sensors at 4:3 or 3:2 because it’s the industry standard and has been for decades. Customizing one to be 16:9 would cost more, stress production, and could require additional modification to the lens design.
The 4:3 aspect ratio is the industry standard in photography because it’s the closes aspect ratio to all of the most common print sizes. Photography wasn’t always digital and history has standardized a series of print sizes. Few of them are exactly 4:3 or 3:2, but printing in these sizes cuts off the least amount of the photo. Printing a 5×7 photo of a 16:9 photo would leave a significant portion of the left and right sides cropped from the image.
You might argue that you don’t care about printing photos, most people just share them online these days. This is true, but even most online spaces to display photos are 4:3 or 3:2. If you look at Facebook’s photo viewer that pops out of the page, the space to hold a photo is almost square, maximizing the size of 4:3 or 3:2 images. While it looks best on your smartphone because it fills the screen, this may not be true for other displays.
Lastly, using the camera in a 16:9 aspect ratio is actually cropping the photo to fit the screen. The reality is the photo is still being captured in the 4:3 or 3:2 aspect ratio at a higher resolution, then getting cropped to fit the 16:9 aspect ratio and losing megapixels in the process. Since this is happening and cropping is destructive to the photos, why not capture it in 4:3 or 3:2, depending on the image sensor. and crop a copy later. This provides you with a higher resolution image that will better fit standard print sizes and various online photo platforms and the cropped version can still fit your phone’s screen completely.