How DSLR Cameras work

Not every beginner in the world of Photography might feel that it is important to understand how DSLR Cameras work. Honestly, you can get by without knowing what makes your camera work. Is it suggested you understand how a DSLR works? Yes! Absolutely.

Understanding how a DSLR works is the first step in becoming one with your tool. Photography terms like Aperture and Shutter speed start making all the sense in the world once you know how the camera works. By this, we do not mean you start reading up on the working of intricate electronics or software. Understanding just the basic working of your camera adds a ton of value to you as a Photographer and lets you truly explore your style with greater freedom.


The Basics:

SLR stands for single lens reflex. DSLR cameras are simply the digital successors of SLR cameras. DSLRs use a digital imaging sensor instead of a film sensor used in an SLR camera.

Now that we know what DSLR stands for, let us actually understand what it does and how a DSLR works.

How DSLR Cameras work

  • You see what the lens sees. This is because light entering the lens is redirected towards the eyepiece in SLRs and DSLRs.
  • DSLRs are perfect for action Photography because of the almost zero lag between what you see and reality. The lack of this is one of the major concerns in case of Mirrorless cameras.
  • The ability to change lenses makes DSLRs the perfect tool for professionals who get the freedom to play around with focal lengths, apertures as well as image quality.
  • Larger image sensor size compared to compact cameras or cell-phone cameras enables photographers to capture images with higher image quality.

A lot goes into the working of a DSLR and to comprehend it all might take one an engineering degree or more. Below we discuss the basics of the working of a DSLR camera. These should be just enough to let you grow and learn on your own by understanding the abilities as well as the limitations of your DSLR.


How DSLR Cameras work

When composing a shot, the image that is visible through the viewfinder is because of the light coming in from the lens reflected by a mirror and prism pair. This is unique to an SLR or a DSLR camera as the same light which will be captured by the sensor is available at the eyepiece. The explains the point mentioned earlier about “you see what the lens sees”.
Note- This image that you see may look different from the final image depending on your settings.



Mirrorless cameras have something called the EVF which stands for electronic view finder (EVF). In case of the EVF, the picture available is the electronic representation of what the captured image will look like. While having its own set of advantages, the lag in case of electronic view finders is something that can be a problem for sports or action photographers.


How DSLR Cameras work

When the shutter is actuated by clicking on the shutter release button, the mirror is raised from its position, allowing light to hit the sensor and capture the image. During this brief moment there is no light reaching the viewfinder of the camera, which results in the momentary darkness each time you take a picture. The shutter speed selected for the shot determines the duration for which the shutter is raised. This is one of the key basics that need to be understood by budding photographers.


Inter-changeable Lenses

How DSLR Cameras work

One of the key benefits of using a DSLR over a phone camera or a point and shoot is the ability to change lenses. A DSLR is made to allow lenses of different types to be mounted on the camera. The countless types and variety of lenses available today mean that there is always a perfect lens for the picture you want to make.

The most common variation amongst these lenses is in terms of focal lengths. Starting from “wide” lenses which are used to capture a large field of view to telephoto lenses which are used to zoom in on a distant subject.

The other type of variation amongst these lenses is how “fast” these lenses are, or in other terms what largest aperture size is available when using them. The reason lenses with large apertures (lower aperture numbers like f/2 or f/1.8) are called “fast” is because they enable the use of faster shutter speeds by opening the aperture wide. There is a ton of information about lenses but the basics covered here should get you started.

Understanding the fundamentals of how a DSLR works for photographers lays a strong logic based foundation. Each time you change a setting, there will be solid logical backing to your decision. This kind of first principle approach lets you truly develop your style and become an artist, not just a photographer.

Hop on to our article about the Fundamentals of Photography- ISO, Aperture and shutter speed to use what you just learned to make brilliant pictures.

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