What is DSLR?

Digital Single-Lens Reflex (Digital SLR or DSLR) are digital cameras that use a mechanical mirror system and pentaprism to direct light from the lens to an optical viewfinder on the back of camera.

DSLRs are often preferred by professional still photographers because they allow an accurate preview of framing close to the moment of exposure, and because DSLRs allow the user to choose from a variety of interchangeable lenses. Most DSLRs also have a function that allows accurate preview of depth of field.

Many professionals also prefer DSLRs for their larger sensors compared to most compact digitals. DSLRs have sensors which are generally closer in the size to the traditional film formats that many current professionals started out using. These large sensors allow for similar depths of field and picture angle to film formats, as well as their comparatively high signal to noise ratio.

The term DSLR generally refers to cameras that resemble 35mm format cameras, although some medium formats cameras are technically DSLRs.

The Advantage of Digital SLR Cameras:
- Build for speed
So why are some compact cameras so slow and digital SLRs so fast? It is electronics vs mechanics.
There's a device called shutter that located in front of the digital SLR sensor for blocking it from light. When you take a photo, the shutter (made up of two curtains) opens and closes. This is different from a compact camera, when there is no shutter mechanism. In compact cameras, the sensor is electronically activated every time you take a photo. The advantage of the mechanical solution is that it is instantaneous: you press the shutter button and the shutter snaps open. There's never a delay when you want to capture that photo of a lifetime. If this was the only advantage of digital SLR cameras, it might be enough for everyone who's frustrated with a sluggish compact camera.

- A Lens for Every Occasion
The ability to exchange lenses, to select the best lens for the current photographic need, and to allow the attachment of specialized lenses, is a key to the popularity of DSLR cameras.

- High Quality in Low-Light
One clear advantage of digital SLR cameras is that they are able to capture photo even when there is not a lot of ambient light.
So what? Every camera can take a photo when there's not a lot of light - just turn on the flash.
Here's the trick: digital SLR cameras can do it without the flash.
Digital SLRs are able to take photos when there's little available light because of a feature called ISO: it makes the digital sensor more sensitive to light.
As you increase the ISO (and increase the camera's sensitivity to light) you also add grain or "noise" to the image.
The advantage of digital SLR cameras when it comes to ISO is that even at high ISO settings they produce very little noise. I can't say the same about compact cameras.
If you really enjoy taking photos when there's not a lot of light, the image quality of a digital SLR will exceed a compact cameras any day of the week.

-You Have Control
This is my favourite advantage of digital SLR cameras.
I don't like a machine to be making decisions for me. While it's right most of the time, it isn't right ALL of the time. The human brain will always be better at judging a scene then a camera set to automatic.
With a digital SLR, you have complete control over every photo you take, and don't have to rely on the camera to make choices for you.
Even if you're not ready to make the jump to a fully manual camera, don't be frightened off/
Every digital SLR camera lets you use an automatic setting, and provides you with the intermediate steps that offer increasing levels of control over your images.