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Comparing smartphone cameras to DSLR cameras is like comparing apples to oranges. True, apples and oranges provide nutrition and sustenance for our bodies but, genetically, they are different. Thus, they have different tastes and textures.

It’s the same with mobile phone and DSLR cameras. As much as they perform the same basic function of capturing images, they are “genetically” different by design.

In this article, we will look at five key differences between these two popular imaging devices.

1. Sensor size (crop factor)

This is perhaps the one main thing that separates the men from the boys because, in this case, size does matter. This is because the bigger the sensor, the more light it can receive. That, in turn, makes for better pictures.

A small sensor is one of the reasons smartphone cameras don’t perform so well in poor lighting (but at least there are several ways to brighten up your mobile shots in low light).

The sensor is the backbone of any digital camera. It’s what captures light information that is then processed into an image. In the days before digital cameras, the light was captured onto film.

The most popular and widely used film format (or size) was 35mm. When digital cameras came into the picture (excuse the pun), the 35mm film was replaced by the 35mm camera sensor. Thus, a DSLR camera with a 35mm sensor is known as a full-frame camera.

However, not every digital camera has a 35mm sensor. Although there are larger formats than 35mm, most of them are smaller than that. Smartphone sensors have always been and still remain at the bottom of the list when it comes to size.

The size of mobile camera sensors is usually commonly expressed in fractions of an inch. For example, the Apple iPhone 11 Max Pro has a sensor that is 1/1.255” in size.

A full-frame 35mm sensor measures 864mm2 while a 1/1.7” smartphone sensor (which is currently the largest of any smartphone sensor and found on the Huawei P30 Pro) only measures 43mm2. That makes it 20x smaller than a full-frame DSLR sensor. That’s a lot!

Sensors smaller than 35mm are known as cropped sensors. This means that any lens attached to a camera with a sensor smaller than 35mm would essentially change focal length, and narrow its angle of view.

In digital photography, the crop factor (also known as the focal length multiplier) is a term that describes the difference in size between any camera’s sensor and that of a 35mm full-frame sensor.

If a sensor’s crop factor is high, then the sensor will capture an image more zoomed in than that of a 35mm sensor if a lens with the same focal length were attached.

The size of the sensor definitely has a huge impact on the quality of the images that the camera can produce. It’s one of the important factors that contribute to what makes a mobile phone photo look amazing. For more on this, check out this simple introduction to smartphone sensors.

A big advantage of having a large sensor is that you can pack a lot of pixels onto it, which raises the number of megapixels the camera has. Not only that, but the pixels are also considerably larger.

2. Pixel size

The surface of a digital camera sensor is made up of millions of pixels. They are the ones responsible for capturing the light that hits the sensor to make an image. The total number of these pixels is referred to as megapixels.

Smartphone manufacturers focus a lot on the megapixel count of their camera in their marketing to the point where consumers believe that the number of megapixels is the most important thing about the camera. You should look into the truth about smartphone camera megapixels.

Even though DSLR camera sensors could pack way more pixels than they already do, they don’t. That’s because although having a large number of them is good for picture resolution, there’s something else that’s also important– the size of the pixels. The bigger the pixels, the more light they can capture.

Pixels are measured in micrometres (equivalent to1 000mm) or microns using the symbol ‘µm’. Currently, the largest pixel size of any smartphone camera is 1.4µm. This is a far cry from the pixel size of a full-frame sensor which can be as much as 8.4µm.

This is part of why even though you may have a smartphone camera and DSLR with the same megapixel count, the resulting images will be nowhere near the same. The camera with the bigger pixel size will most likely come out on top.

To better understand this, think of pixels as buckets that catch rainwater. Rainwater represents light in this analogy. A big bucket will catch more rainwater than a tiny cup.

The good thing about large pixels is that they are not as prone to digital noise as small pixels are. Any and every electronic piece of equipment generates heat and has an inherent noise floor. The noise becomes more and more apparent when raising the electronic signal to brighten up the image, thus boosting the signal to noise ratio.

Going back to the bucket and rainwater analogy, if you’ve ever collected rainwater before, you’ll know that the water collected is not entirely clean. Some dirt settles at the bottom of the container.

This is not too much of a problem if you have a large bucket because you still have a lot of good water you can use. Rainwater collected in a small cup is very little, so having dirt in it is a problem because it brings down the water to dirt ratio.

This is why smartphone cameras don’t perform as well as DSLRs in low light conditions. Because their pixels are so small, they can’t capture enough light if the lighting conditions are poor. You can increase the brightness by turning up the ISO but you run the risk of introducing digital noise.

With large pixels found in DSLRs, you can get great shots in low lighting. Obviously, not all cameras are the same, so the quality of the images is camera dependent. Still, they outperform smartphone cameras in this regard.

But that’s not to say that you can’t avoid digital noise when taking photos with your smartphone camera at night. You can. I suggest you read up on what digital noise is, and how to avoid it.

3. Aperture

Aperture refers to the diameter of the opening through which light enters the camera’s lens. How dark or bright the image will be is determined by the size of this opening which is expressed in f-stops. The smaller the f-stop number, the wider the opening and, ultimately, the more light reaches the sensor.

A DSLR camera’s lens barrel has a mechanical diaphragm that controls how much light goes through and reaches the sensor. There’s a ring on the lens barrel that you can turn to adjust the size of the aperture.

Being able to change the aperture allows you to creatively manipulate things like depth-of-field, which is achieved by shooting with a larger aperture. This works especially well for portraits.

On the other hand, if you’re shooting things like landscapes, the best thing to have is a deep depth-of-field so everything in the foreground and background can be in focus. This can be achieved by narrowing the aperture.

Things are not quite the same, however, when it comes to mobile cameras. Unlike with DSLRs lenses, smartphone cameras don’t have adjustable aperture settings. This means whatever aperture the mobile camera is said to have, that’s it. It cannot be changed.

This is a major bummer because aperture plays as equal a role in the Exposure Triangle as ISO and shutter speed. This is the balance you need to set between these three settings in order to expose your images to your liking with minimal noise and as little or as much motion blur you want.

So, when you’re taking photos with your mobile camera using Manual mode (which you should learn to do for these three good reasons), you can only adjust how bright the image is by adjusting ISO (the sensor’s sensitivity to light) and shutter speed (how long the sensor is activated to capture light).

This raises the question; does the exposure triangle matter in smartphone photography? And if so, how does it work?

Also, check out this article to learn more about aperture on smartphone cameras and also see what Samsung tried to do with a variable aperture on their flagship camera phones.

4. Lenses (Focal length & focal equivalent)

This is perhaps the most obvious difference between a DSLR camera and a mobile camera. Although not all DSLR cameras have detachable lenses, they’re pretty standard in a lot of DSLR cameras.

Smartphone cameras, however, do not have this ability at all. Sure, you can attach external lenses to your phone’s camera but these come nowhere near what you can achieve with proper camera lenses.

To better understand the key difference between smartphone lenses and DSLR lenses, you need to understand what focal length is and how it affects the image. Because I discuss that topic at length in this article about mobile camera lens focal length, I won’t go into detail about it here. So, be sure to check it out.

But simply put, the focal length of a lens tells you the distance between where light converges in the lens to the image sensor. From the focal length number, which is measured in millimetres, you are able to know the angle-of-view (also known as field-of-view) and the magnification of the lens.


The longer the focal length, the less of the scene you’ll see, and the more magnified your subject will appear. The shorter the focal length, the wider the angle of view, which means you get to capture more of the surrounding scene.


For example, a DSLR telephoto lens can have a focal length of anything from about 70mm upwards. This is great for wildlife and sports photography or whenever you need to take photos from a distance such as at events provided the focal length is long enough for your needs.

A lens with a long focal length is easily identifiable by its length. The longer and bigger the lens, the longer the focal length. Wide-angle lenses are much shorter since their focal lengths range from anything between about 24mm and 35mm.

If you look at the specifications of a mobile camera, you’ll notice that the focal lengths of their lenses are said to be around 24mm for wide-angle lenses and even up to 135mm in some telephoto lenses. However, this is technically impossible because smartphone cameras and their lenses are just too small to have such focal lengths.

The reality is that the focal length numbers stated in the specs of mobile cameras are stated as equivalent to those of a 35mm full-frame camera. The actual focal length of smartphone camera lenses is much, much shorter than what’s stated.

For example, a phone camera that is said to have a 26mm focal length might only have an actual focal length of only roughly 4mm or so. That’s significantly smaller than that of a DSLR. So, where does the 26mm come from, then?

Remember earlier I mentioned crop factor? If you take the actual focal length of the lens and multiply it by the crop factor of the sensor, you’ll get the 35mm equivalent. This basically says that if this camera had a 35mm sensor, then this is what the focal length would be.

This way it makes it easier to get an idea of the angle of view you’ll get from that lens by comparing it to a standardized size.

If this doesn’t make a lot of sense, again, I recommend you check out the article ‘Understanding Focal Length On Smartphone Cameras’. It sheds a lot of light on this topic in an easy to understand manner.

5. Optical zoom

Also related to the topic of lenses and focal length is the issue of optical zoom. So far, when talking about DSLR lenses, the main focus was fixed lenses that don’t zoom. These are known as prime lenses and their focal length never changes.

DSLR zoom lenses, on the other hand, are made up of several glass elements inside the lens barrel that move back and forth to either magnify the image (zoom in) or make it smaller (zoom out). As these glass elements move, the focal length changes.

For example, a lens that is said to 18-55mm means that it can change its focal length from 18mm (wide-angle shot) and zoom in to a 55mm focal length, which gives a narrower field of view. This all happens without heavily degrading the picture quality of the image.

Due to their size and design, for a long time, smartphone cameras have relied mostly on digital zoom. However, this is an inferior form of a zoom that lowers the picture quality because it’s not really zooming in. Instead, digital zoom just crops the image and then enlarges digitally.

Because size matters in smartphones, you won’t find a phone camera these days with a lens that sticks out from the back, although some have tried in the past. The solution was to introduce phones with multiple cameras, each with lenses of different focal lengths.

In many instances, you’ll find that these phones have a wide-angle lens of somewhere in the range of 26mm and a telephoto lens in the range of 52mm or so. This gives the phone camera 2x optical zoom.

However, this is technically not true optical zoom but rather a hybrid zoom because the camera still needs to use AI to interpolate pixels as it switches from the wide-angle camera to the telephoto camera.

The results are still better than digital zoom though only up to 2x. Zooming in further than that introduces digital zoom. So, this technology is rather limited.

Enter the periscope camera. In recent times, more and more high-end phone companies have started to include a periscope camera to their flagship devices. This was pioneered by Huawei with the P30 Pro, which made waves with its optical zoom capabilities.


A periscope camera is designed in such a way that the camera unit is positioned sideways instead of parallel to the back of the phone. A prism is positioned where light enters the camera and reflects the light at a 90-degree angle, so it goes through the zoom lens array and finally reaches the sensor.

This technology, which you can read about in more detail here, allows a mobile camera to reach up to 5x optical zoom and perhaps even more, depending on the design. Impressive as this is, it’s still nowhere near what you can achieve with a good traditional DSLR camera lens.

One thing that the smartphone camera and the DSLR camera have in common when it comes to zoom is that the more you zoom in, the shakier your shot will be. This can lead to blurry photos.


In my humble opinion, these are the main differences that set DSLRs and smartphone cameras apart. Are there more differences? Sure, and these can be anything from design to cost, or flash technology to the amount of AI being used.

A lot of people would even argue that you can’t run a photography business using just a smartphone camera. And that may be true. It would be a struggle. But at least there are some ways to make some extra cash with your mobile photos.

However, I think the points mentioned above are ultimately what leads to the difference between the two types of cameras, especially when it comes to picture quality.

Despite being inferior to DSLR cameras, you can still take some awesome photos with your phone, provided it has a good mobile camera.

This article first appeared on my other blog Check it out!

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