What is a DSLR Camera?

DSLR cameras have been the iconic standard for most professional photographers. There are a wide variety of models for both amateur and advanced users. However, since the rise of mirrorless cameras, DSLRs have become slightly less popular, but there are a few reasons why they still remain the preferred camera for many. 


DSLR stands for digital single-lens reflex. The digital part means that it works with a digital, fixed sensor. The single lens means the camera uses the same apparatus for framing, focusing, and then snapping the photograph. This makes the DSLR different from rangefinders and other twin-lens-reflex camera bodies. 

The reflex refers to the mirror system used by DSLR cameras. The light that enters through the single lens is directed by a mirror upwards to a block of glass called the pentaprism. A pentaprism reflects an image to the optical viewfinder, where you can view the exact scene you are about to shoot. 

When the shutter is pressed to take a picture, the mirror flips up out of the way in DSLR cameras, making the viewfinder go dark. The shutter then opens to expose the imaging sensor to light, then closes after a set amount of time to snap the photo. 

DSLR cameras have the same body and mechanics as past 35mm film cameras. Those cameras that use film are simply known as SLRs. DSLRs use a digital sensor to record images instead of film.

The components that make up a DSLR camera include the lens, the reflex mirror, the shutter, an image sensor, a focusing screen, the condenser lens, the pentaprism, and the optical viewfinder. All of the moving parts inside the camera body make it bulkier and heavier compared to its mirrorless counterparts. 

SLRs have been in the market for about a century and can be found almost anywhere for a reasonable price. They range from entry-level cameras to extremely high-quality models. However, the elements, such as the lenses, are interchangeable. That means you can buy a bare camera body and a highly professional lens to attach to it. It allows plenty of options for any budget. 

Key Features

There are many similarities between mirrorless and DSLR cameras. Mirrorless cameras have fewer moving parts, making them lighter and more compact. However, DSLRs still carry some superior vital features that make them a preferred option for both beginners and professionals. 

Interchangeable lenses

Like mirrorless cameras, DSLRs have interchangeable lenses. That means you can remove them and attach different lenses to fit your needs. Lenses that range in different focal lengths allow both DSLR and mirrorless cameras to take shots that are both close and far away. 

The lens manipulates the form of the image according to what the photographer wants. They play a significant role in the contrast, clarity, and color of every photograph you take. You can mount a wide-angle lens to snap landscapes or architecture or use a fisheye lens for more creative shots. With a DSLR camera, the number of interchangeable lenses available is incredibly large. 

Each manufacturer produces its own mounting system and lenses that accompany it. Third-party producers often make their lenses available to use with multiple mounting systems. You can even use adapters to attach older lenses to DSLRs. 

Optical viewfinder

DSLR cameras use an optical viewfinder, which allows the photographer to see through the camera’s single lens at the moment. It reflects the light directly to your eye so you can see a clear, sharp image of the scene you will capture. However, it does not let you view the final shot or know how the exposure or contrast will affect the photo. 

When you look through the optical viewfinder on a DSLR camera, a few things are displayed besides the focusing points. The first set of digits on the bottom is the shutter speed, which is then followed by the aperture level. Those numbers help you adjust your camera settings when you shoot in manual so you can get the right photo. 

There will also be a scale with a marker, which represents your exposure level. When the marker is in the middle, that means the image is being exposed correctly. If it is too far to the left or right, that means your photo may be underexposed or overexposed. 

Suppose you are shooting in challenging conditions or in low lighting. In that case, a DSLR camera makes it easier to capture photos because the optical viewfinder does not alter the image, unlike electronic viewfinders, which can make the preview image look blurred or grainy. 


DSLRs use a focusing system called phase detection, which measures the intersection of two beams of light. In autofocus, a small portion of the light that enters passes through the primary mirror in order to hit the secondary mirror. The second mirror sends the light to the autofocusing sensor, where it quickly focuses on the subject at hand. 

The DSLR camera is extremely fast in autofocus performance and can be used to capture quality shots of moving objects. The lens’s quality also affects the camera’s focus and accuracy, but overall, the DSLR has high-speed autofocus capabilities. 

Image quality

The quality of images from a DSLR camera depends on the size of the image sensor. Larger sensors offer higher resolution and better image quality compared to smaller ones. The standard formats of DSLR sensor sizes are the full-frame, which is the standard 35mm film format. Cameras like the Nikon D-series use full-frame sensors. 

The APS-C sensor renders at around 40% of a full frame. The four-thirds system, which was created by Eastman Kodak and Olympus, is a smaller sensor that displays 26% of the frame. An even smaller version of that is the Micro four-thirds. 

Smaller sensors affect the quality of an image, so depending on what you are going for, choosing a DSLR with a larger sensor will give you higher image quality. 


In DSLR cameras, the sensor’s size, not the megapixel count, determines the image quality over other camera types. The two main types of sensors of DSLR cameras are the full-frame and APS-C, or crop frame. 

The size of a full-frame camera sensor is the same as a 35mm film SLR. They are often found in higher-end DSLRs and can have a starting price of about $2,000 for newer models. Cameras with full-frame sensors are often bulkier compared to cameras with smaller sensors. However, they offer incredible image quality because they have a larger surface area, especially in low-light settings. 

Full-frame sensors also have a better depth of field control. That means they have an increased depth of field, unlike smaller sensors, which require a wider lens and distance to create the same effect. 

APS-C sensors are about half the size of full-frames at about 40%, which often creates what is known as a “crop factor.” The “crop factor” refers to the changes to the field of view that occur with different sensor sizes. A smaller sensor crops the image with an added “zoom.” While it may be nice because it has a slightly longer depth of field, you cannot get the same wide shot even with a wide-angle lens compared to a full-frame camera. 

Cameras with smaller sensors are more compact and more comfortable to travel with. They can also use particular lenses designed for cropped sensors, and these cameras are often cheaper than their full-frame counterparts. It is also easier for these smaller sensors to use long zoom lenses for incredible range. 


Consider the potential advantages of DSLR cameras; cost for the value, accessory availability, and more.

Cost value

While DSLRs can be wildly expensive for high-end models, many third parties sell these models, making the cost of the camera body lower overall. You can find DSLRs for as low as $150 for some of the cheapest models, while high-quality ones go into the thousands. 

The accessories and lenses available for DSLRs are also more generous than mirrorless cameras. That means you can attach high-quality lenses to cheaper DSLR camera bodies, making the cost value of the DSLR higher and giving plenty of options for every budget. 

Wide variety of accessories

Since DSLR cameras have been around for a long time, there are a plethora of accessories and lenses from a range of manufacturers. You can find basic lenses for cheap or invest in professional accessories for much higher prices. There are hundreds, if not thousands, of lenses available for DSLRs from various manufacturers, while the options for mirrorless cameras are much less. 

There are a variety of other accessories available for the DSLR, such as speed lights or flashes. Most DSLRs include a hot shoe, which is an electrified mount that sits on top of the camera. You can attach external flashes, microphones, or trigger systems to it, among other accessories. It gives greater versatility to what your camera can do. 

Quick autofocus

Phase detection is a quick and superior way for cameras to focus on objects. It’s an autofocus system that measures the convergence of two light beams. This allows DSLRs to focus exceptionally quickly to capture quality images regardless of the scene’s lighting. They are excellent cameras to capture fast-moving subjects, such as wildlife or sporting events. 

In contrast, mirrorless cameras tend to use slower contrast detection autofocus technology. However, in recent years, mirrorless cameras are beginning to use similar autofocus technology to make them comparable to DSLRs. 

Longer battery life

DSLR cameras generally offer a longer battery life compared to mirrorless cameras. This is because they can shoot without needing to provide a live image on an electronic viewfinder or LCD screen. DSLRs can take thousands of shots per charge, while mirrorless cameras take less than 500 per charge. That makes DSLRs the ideal camera to take for longer shoots. 


DSLR cameras do have a few notable disadvantages as well.


DSLRs are some of the industry’s most massive cameras because of their several moving parts and many accessories. As technology advances, mirrorless cameras are becoming a lighter alternative to the bulkiness of the DSLRs with many of the same functions. They are also easier to travel with because they are more compact. 

DSLR cameras can weigh up to 2 ½ pounds and are much bigger than other camera types. The various lenses and accessories on top of a bulky camera can make it a heavyweight to carry around. 

Doesn’t offer real-time previews

While the optical viewfinder allows you to see the scene exactly as the camera lens views it, the display options are limited. Unlike electronic viewfinders, you cannot preview an image’s current exposure before taking the first shot. 

With DSLRs, you need to first take the photo in order to adjust the settings to get the image that you want. You may end up taking dozens of pictures trying to get the exposure and contrast right. This may work well for more experienced photographers who can quickly adjust the exposure and contrast, but it may be challenging to manage for newer users. 

Some DSLRs offer a “live view” mode that mimics the electronic viewfinder’s capability. It raises a mirror so you can see a preview of your image. However, the focusing performance of some lower-cost DSLRs slows down in this mode. 

Lacks quality video capabilities

DSLRs were once preferred for videography because of their video clarity. Newer models have been making a move to high resolution with Ultra HD. However, because DSLRs do not have an LCD screen or real-time displays, mirrorless cameras with electronic viewfinders are becoming more popular for video recordings. 

Most DSLR cameras cannot use phase detection to focus while recording a video, so they need to use contrast detection in order to focus, which is slower and less accurate. That leads to blurry moments in the middle of a video when it tries to find the right focus. 


DSLR cameras have a variety of incredible features that appeal to both entry-level photographers and experienced professionals. It is beneficial to know the advantages and disadvantages of a DSLR when looking to purchase your own. Let us know how you like DSLR cameras in the comments, and share if you liked this article!

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