Does the size of camera sensors matter?

One of the main features of any camera, whether it is a aim and shootmirrorless model or even a smartphone camera — is the size of the image sensor. It’s clear in the marketing that a larger image sensor is better, but why? Does a small increase in sensor size really make a big difference? When looking for a new camera or phone, should you consider sensor size?

The truth is that maybe. In some situations, a larger image sensor can have significant advantages over a smaller sensor, but the specifics matter. Different lenses, technologies like pixel binning, and advanced computer image processing techniques can all help small sensors perform more like larger ones. Also, depending on the type of photos you’re taking, it might not matter at all. Here’s why.

The basics

An image sensor is a device that absorbs light and converts it into electrical signals which are then interpreted by the camera’s (or phone’s) processor to create an image. They are designed to absorb as much light as possible. Modern image sensors are quite good in this area, certainly compared to those found in cameras from the early days of digital photography.

At the risk of stating the obvious, there is plenty of light available during the day. Indoors or at night, not so much. Your eyes can easily adapt to these extremes, but small image sensors often struggle. With less surface area to capture light, they can produce images that are too dark – assuming they capture a usable image.

A larger image sensor, all things being equal, has more surface area to capture light. To put it simply, imagine that it is raining and you want to collect some water. If you go out with a shot glass, you’ll catch some. If you go out with a bucket, you’ll catch a lot more. The same principle applies to image sensors, although the details are a little – okay, a lot – more complex.

Sensor sizes

Image sensors – our rain buckets, if you will – come in a variety of sizes. In product marketing, you’ll often see terms like “1-inch,” “APS-C,” and “full frame.” They are descriptive without being particularly clear. For example, a 1-inch sensor doesn’t actually measure 1 inch in any dimension, including its diagonal measurement.

This colorful illustration, skillfully done by yours truly, should give you an idea of ​​the relative sizes of some of the more common image sensors.

I can’t make this graphic appear full size on every phone, tablet, and computer, but if you remember from film, a full frame sensor is about the same size as a single frame of 35mm film. If not, an APS-C sensor is just under an inch wide and a little over an inch diagonal.

Remember, these are the physical sizes of the image sensors. The resolution, that is to say the number of pixels they have, is distinct. You can have a 50-megapixel 1/1.28-inch sensor and a 24-megapixel full-frame, and vice versa. Resolution determines the pixel size for each sensor, which in theory will mean more light absorbed for a lower resolution sensor of a given size. As with two sensors of the same size, the one with the lower resolution will generally have larger pixels, which could mean it’s able to absorb more light, but the sensitivity of the specific sensor and other factors mean it’s not 100% directly comparable to the numbers.

Where do these sizes come from? This is a holdover from the days of analog television and refers to the diameter of a theoretical vacuum tube with light-collecting electronics about the same size as a modern sensor. I’m not kidding. Technically, the more accurate term is “1-inch type sensor”, but it is usually abbreviated to “1-inch sensor” because it is easier to read.

Technology: group those pixels and stack those images

So yes, generally speaking, a larger image sensor will capture more light than a smaller one. This can mean that the camera with the larger sensor is better in low light, able to create an image with less noise and less image processing, as well as many other subjective and objective benefits. However, in many situations the differences will be much smaller than their relative magnitude suggests.

Let’s start with an easy to understand one. All major phones now have an HDR photo mode, often enabled by default. It is different from HDR on your TV. With photos, this means the camera takes multiple images and combines them. In the simplest case, it captures a slightly underexposed image (too dark), a correctly exposed image, and an overexposed image (too bright). The phone will then combine these images so that the final result contains more shadow detail and more highlight detail than a single image with the same image sensor could have done. While this doesn’t always work with perfect results, when it does work, it allows the camera to punch above its weight, so to speak.

This same technique, more or less, is used in the night, night vision or astrophotography modes found in most high-end phones. The phone takes multiple images, then aligns them and performs heavy computational photography that reduces noise and increases brightness by comparing all the images. This allows the camera’s small sensor to capture much more light than it could with a single exposure – or at least with a single exposure short enough to avoid visible blur from camera shake.

Pixel binning is another technology. This is where groups of pixels are treated as a single pixel. This effectively makes each pixel “bigger” and able to capture more light. Using this technique results in a photo with lower resolution than the sensor is technically capable of, but the image quality may be better. Details aren’t everything, especially when the tradeoff is better dynamic range and generally less noise.

Then there is the goal. A “faster” lens lets in more light than a “slower” lens. While the difference isn’t usually huge on phones, you might be surprised how noticeable a numerically small difference can be. With a faster lens, that is, a bright lens, even just a half stop can let in significantly more light, potentially offsetting some or all of the potential drawbacks of a smaller sensor. There are almost endless camera and lens combinations, so details matter. That’s something else to keep in mind when comparing specs.

Finally, there is the sensor technology itself. Two identically sized sensors could perform radically differently depending on their design and technology. A full-frame sensor from 15 years ago might have worse dynamic range than an APS-C sensor released this year. There are a lot of variables. Often, but not always, full-frame sensors are found in high-end consumer cameras and typically feature the latest sensor technology and performance.

When it might not matter

As a photographer, I can definitely notice the difference between a photo taken on a phone and a photo taken with a standalone camera with a large image sensor. Generally, the image has less noise, more authentic details, more natural bokeh, and better overall image quality. What’s less obvious are photos taken with image sensors with similar but marketable size differences. I’ve owned a full-frame camera for years and love it, but over the last year, almost all of the photos I’ve taken that I really like have been taken with a camera with a smaller APS-C sensor. I don’t think any of these images would have been improved – or even significantly different – if they had been taken with a full-frame camera.

To answer the question posed in the title: Yes, the size of the camera sensors matters. However, the camera and the photographer matter more. If you don’t like photography, the difference in the end result won’t be huge, especially considering the advanced features found in many devices with smaller image sensors. A camera or phone with a 1/1.9-inch sensor and one with a 1/1.28-inch sensor will differ in too many other ways to determine which one will take the best photos based on sensor size alone. For years, for example, Google Pixel phones used smaller image sensors than comparable Samsung and Apple devices, but produced better low-light images thanks to superior computational photography.

If the camera does not have these features, such as Panasonic Lumix ZS99the biggest difference will be poor low-light performance. However, this camera’s impressive optical zoom still makes it attractive in many situations. So, as with anything, check reviews and non-marketing sample images to see how the camera performs.

For the most part, if you’re just posting images to social media and aren’t looking to take the ultimate photo in image quality, the size of the image sensor won’t make much difference.

If you enjoy photography – or are looking to get into it – there are many factors to consider when choosing which camera is best for you. The adage that “the best camera is the one you have with you” is still true. As I mentioned earlier, I returned to an APS-C camera after years of shooting with a full-frame model. The smaller sensor is better suited to my needs in many ways, and the camera itself is lighter, more compact, and easier to carry. Would I upgrade to a medium format camera if I had the chance? Given the cost and size of these systems, probably not. For the way I travel, this would be more of a burden than a benefit. However, I haven’t sold my full frame camera, and when I’m at home it’s still more than capable of handling my professional work.

My advice, and I’m assuming you’re relatively new to photography if you’ve read this far, is to get a camera you can easily afford, along with a few good lenses and get to know them inside and out. Once you learn some skills, you’ll probably have a better idea of ​​what a more expensive camera with a larger sensor can do for you. Maybe you want a wider field of view than you can get with a smaller sensor or images with less noise and low light. Or maybe you want the narrowest depth of field possible so you can miss 90% of your photos because they’re blurry (I’ve been there). At this point you can see what’s shiny and new. Or even better, what you can find second-hand at a reduced price.

About the author: In addition to covering audio and display technology, Geoff takes photo tours of cool museums and locations around the world, including nuclear submarines, aircraft carriers, medieval castles, epic 10,000 mile road trips and much more.

Also see Budget travel for dummieshis travel diary and his best-selling science fiction novel on city-sized submarines. You can follow him on Instagram and YouTube.