DSLR | Full Form and Why It Is Called So.

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The full form of DSLR is Digital Single Lens Reflex.

But…have you ever wondered why is it called so?

I will tell you why.

Old Camera

DSLRs are basically the evolved form of the SLRs. SLR stands for…. as you have already guessed, Single Lens Reflex. Let me explain the nomenclature a little bit so that it is easier for you to understand the rationale behind it.

Bit By Bit:

Digital: Since the final image is captured on a Digital Image Sensor and NOT on film. Film cameras were called only SLRs remember.

Single Lens: This requires a little longer explanation. If you poke around a bit, you will find that there are many types of cameras, DSLRs, Mirrorless, 4/3 format, Micro 4/3 format, et cetera. Each of these cameras have a specific characteristic that gives it the name.

Mirrorless Camera
Mirrorless Camera (Lumix G1)

In the case of DSLRs, the cameras use a SINGLE lens for the entire camera. Rangefinder cameras on the other hand generally have two set of lenses. One for the camera to see through and the other on the viewfinder for the photographer to see through.

Due to these basic and fundamental changes, many things in the various camera types are also different. The auto-focusing, light metering, etc function in different ways in all these cameras. . Anyhow coming back to the question of DSLRs, we see that the camera uses a single lens for both the camera and the viewfinder; hence “Single Lens”.

Leica M9
Leica M9

 Reflex: The word reflex is used to denote the way light passes THROUGH the camera. What essentially happens is that the light enters the camera through the lens; passes through the lens elements; which are basically different types of glass that are there on the lens barrel; falls on a mirror which is placed at a 45 degree angle (inside the camera); reflects off it into a prism above it and finally comes out of the viewfinder. This elaborate process ensures that the photographer “sees” exactly what the camera is seeing.

Why DSLRs Became The Most Widespread And Commonly Used Cameras

The first and foremost reason would be lens interchangeability. Previously cameras came with fixed lenses, DSLRs changed all that. Now you can use a specific lens for that exact specific scene or type of photography and thanks to the elaborate and exhaustive range of lenses form manufacturers such as Nikon and Canon, life has suddenly become worth living.

DSLRs nikkor lenses

Next on my list would be Image Stabilization.

Image stabilization is a technology that ensure that the camera experiences as little shake and movement as possible so that it can take sharp, crisp photographs. In other words it compensates for you, when you cannot keep the camera very steady.

Mainly there are two types of stabilization;

  • In-Body Image Stabilization
  • In-Lens Image Stabilization.

Image Stabilization

Last but by far one of the most important reasons why DSLRs are so popular even today in this age of mirrorless cameras is because of the ability to auto-focus very fast. Though mirrorless cameras are making very large strides in this area, I will have to say that DSLRs still rule the roost. With its advanced technologies such as PDAF (Phase Detect Autofocus) and CDAF (Contrast Detect Autofocus), I personally believe DSLR’s are much faster and more reliable in this regard. People may disagree with me on this though.

There are many types of DSLRs as well in the market. Most common types are Cropped Sensor, Full Frame Sensor, 4/3rds etc. I have not included micro 4/3rds since they do not exactly fit the definition of DSLRs. They generally have an EVF (Electronic Viewfinder) that is like a mini-screen place where otherwise the OVF (Optical Viewfinder) would be, much like mirrorless cameras.