If one of the first days of mobile phones comes to our day, the fact that the most we care about in our phones is the camera, it will probably confuse our time traveler.
Phone cameras were pretty useless in the past, but the ability to have a camera with you wherever you go made them extremely popular. That’s why manufacturers put an absolute fortune into camera development, and now we have camera phones that can give professional cameras great value for money. At least under the right circumstances.
However, one thing that relatively few smartphone cameras have in common is optical zoom. However, with the passage of time you will start seeing it on newer phones. It provides the perfect time to discuss optical and digital zooming.
What is “Zoom”?
You probably already know what Camera Zoom is. At least you know what you’re doing. “Zoom” is a function that makes distant subjects in your photo appear up close. Effect on photo is to re-frame the photo by allowing the subject or person to fill more space.
There are various ways to achieve this effect, but most smartphone cameras use a method called digital zoom. To understand how optical zoom differs from the digital zoom method we currently use, we must first explain digital zoom as it is currently used in most phones.
What is Digital Zoom?
Digital zooming is similar to cropping and resizing a photo in an app like Photoshop. The main difference is that you do it live while taking a photo or shooting a video. So what’s important? It’s all reduced to pixels. Where does “digital” in digital zoom come from?
When you enlarge a digital image, it becomes more “pixels”. This is because you have a fixed source of pixels. The only way to zoom in is to enlarge the pixels. The image becomes grainy, thin and becomes a poor quality picture.
This sounds a bit disastrous for a smartphone, but over the years various tricks have been developed by smartphone makers to reduce the effects of pixelation on digitally zoomed images. Because modern phone cameras have sensors that can capture more pixels than is usually needed. So you can crop to a fraction of the full sensor resolution without any loss of quality.
It’s fine if you want to take a social media friendly photo, but if you want to take a photo at your camera’s full resolution, you can’t zoom in on any part of the photo without losing details.
Most people probably don’t mind having large, full-resolution images that can’t be uploaded to Facebook or Instagram in real quality. However, more and more people are taking smartphone photography very seriously. This means there is a market for more premium solutions. This is where optical zoom in the picture comes in.
What is optical zoom?
Optical zoom is a zoom method that uses light to magnify an image. It works similar to a magnifying glass and bends light through an optical medium (lens) to form a larger image.
In specialized cameras like DSLRs (digital single-lens reflex cameras), you have large lens assemblies that can zoom in by physically moving the lens back and forth. This changes the focal length between the lens and the camera sensor. Projecting a magnified image over the entire sensor.
As you can probably tell from the way it works, this means that the magnified image projected from the lens covers the entire sensor in light with full resolution. This means that a zoomed image contains only as much detail as the entire image from a digital zoom camera. Truly lossless image enlargement.
Which phones have optical zoom?
Taking optical zoom on a smartphone is not a trivial matter. You can’t really have a big motorized lens assembly on the back of the phone. Still, it’s actually been tried. For example, the Samsung Galaxy S4 Zoom was essentially a smartphone with a compact digital camera on the back. Take a look at this:
Obviously this isn’t something you can fit in your pocket, so this approach has never really caught on. Instead, modern smartphones stick a bunch of cameras on the back of our phones. Each camera has a different focal length range, so when you put all the cameras together you get an optical zoom range.
For example, this is not the same as a large telephoto lens on a DSLR. This is because you can shift the focal length of the telephoto lens to focus the image at different zoom levels on the same sensor. The problem is that most multi-camera smartphone setups have separate sensors for each lens. The main camera usually has the largest sensor with the highest pixel count. With wide-angle and telephoto cameras with smaller, cheaper sensors.
Doesn’t this miss the whole point? In a sense it does, but the multi-camera setup still offers the best high-quality zoom range on a phone. Engineers have found ways to combine these different approaches to zoom in on something greater than the sum of its parts.
Best for using both optical zoom and digital zoom
So-called “hybrid” zoom systems use the optical capabilities of onboard cameras with digital zoom and are known as “computational photography”.
Computational photography refers to a set of software techniques that a camera can capture using artificial intelligence and other fancy mathematical methods to manipulate and enhance images. For example, artificial intelligence can increase the resolution of an image by “imagining” how it will look at a higher resolution.
It may sound like magic but it actually works great in most situations. Such software techniques can also help combine different images from onboard cameras to enhance the details of photos at the upper end of the optical zoom range. Even when digital zooms are engaged, all these image data sources and clever software algorithms can create some pretty stunning images.
best optical zoom phone
iphone 12High-end smartphones like high-end smartphones have a good optical zoom range. It’s not really a “telephoto” by any stretch of the imagination, but you can generally expect a 2x to 2.5x increase in image size with no pixels. This is great for general use cases like taking a picture of something you can’t physically get close to.
Sure it’s a nice feature, but most users will be very happy with the digital zoom. Especially when enriched with a nice dollop of artificial intelligence. If phones start offering more than 2.5x optical zoom range at the same resolution as the main sensor, it’s time to sit down and take notice. However, at the time of writing this is not a feature that should influence your buying decision.
