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Do you want to understand your camera and take great photos today?

Yes Please

DSLR cameras are the standard, most popular camera choice by far. They are versatile and offer professional photographs. They can also work with an array of lens types.

Models range from entry-level to very expensive full-frame systems.

This article will give you all the info you need on what a DSLR is.

A Canon DSLR camera resting on a table outdoors

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What Is an SLR Camera?

Whatever your budget, whatever your subject, a DSLR is a great choice of camera. But what does DSLR  stand for and what does it even mean?

DSLR stands for Digital Single-Lens Reflex. I can still see people scratching their heads, so let’s expand. The digital part we know, but the other parts are more confusing.

A Single-Lens means just that. The SLR that you photograph with has one lens, where the light will travel through to hit the film.

The digital aspect means that we no longer use film, but a digital sensor. They both work the same way. Digital photography allows you to see the image almost immediately.

This might seem obvious, but not all cameras work with one lens. An SLR is an advancement on what is known as a TLR; Twin-Lens Reflex. 

A Nikon DSLR next to a Canon Single-Lens Reflex

What Is a TLR Camera?

In the early stages of photography, cameras used glass plates. These were coated with a light-sensitive emulsion.

The body of the camera held the glass plate and allowed you to focus the image. But you couldn’t do both at the same time.

This caused problems, and due to these, in 1870 the Twin-Lens Reflex was born. The revolutionary system allowed you to get that sharp focus while the glass plate sat at the back.

This was down to having two lenses; one to focus and one to take the picture.

These cameras would have a viewfinder on the top, which you look down into. These cameras were medium format, so their glass (and then film) measured either 6×4.5″, 6×6″ or 6×7″.

The film used with these cameras today is known as 120 film, whereas the SLRs use 35mm film.

These Twin-lens cameras were a huge step in the right direction but created new problems. Having a different lens that you would focus with, and another to take the photograph was the problem.

The two different views would never match up, as one lens was above the other. For landscapes, this wasn’t really a problem.

But the closer the subject, the bigger the parallax error, lowering the image quality.

A Rolleiflex medium format Twin-Lens Reflex - what is a DSLR camera?

Parallax Error

A parallax is the difference in the apparent position of an object viewed along two different lines of sight.

We have this in our eyes as there is a distance between our pupils, which shows each one as a different perspective.

This concept is what helped camera manufacturers to create the SLR. One lens, one view, one perspective.

We know about SL & TL now, but what about the R? The Reflex is how we see the image – with reflection. Inside each of these cameras is a mirror. This bounces the light from objects so that you can see them in the viewfinder.

The mirror in the TLR doesn’t move, but in the SLR, the mirror has to flick up to let the light hit the film. This mirror, set at a 45°, separates the viewfinder from the film plane.

When you release the shutter, this is what forces the mirror out of the light’s path.

The inside of a Rolleicord showing parallax error

Image Credit: Images and Cameras

What Is a DSLR Camera?

The small format, 35mm single-lens reflexes entered the scene around 1920. It wasn’t until 1999 for the first DSLR camera to appear – from camera manufacturer Nikon. It cost $6000 and had an effective 2.74 megapixels.

These digital versions still kept the mirror system. They used one lens to frame and capture the subject.

Your options today include the Canon EOS 5DS R. It costs $4000 and offers 50.6-megapixel resolution.

Benefits of a DSLR

The benefits of having an SLR over a TLR was that they were less bulky. Better lenses were created for the SLR, as some TLR didn’t have any zoom lenses available. The parallax error is a big problem when it comes to not seeing exactly what you are photographing.

Having a TLR does have a few benefits. Personally, I like the way it feels as it is a special camera that most people have never used. I use it for street photography, as it helps to keep my camera away from my face, which gives me candid photographs.

The advantages of having a Digital SLR over an SLR comes down to that D. The former is digital. This allows you to capture an image on a digital sensor instead of film.

Photographic film is expensive, especially in relation to photographing multiple images.

With dslr photography, you could take hundreds of photographs of a subject.

The same amount of photographs with a film camera would mean many rolls of film. These take space, can be expensive to buy and then expensive to develop and print.

As long as you have the right adapters, you could even use the old analogue SLR lenses on your Digital SLR body.

If you are wondering which DSLR camera might be a good choice for you – read our article here.

The Canon EOS 5DS R DSLR

The Future

DSLR Vs. Point-and-Shoot

Point-and-shoot cameras are a faster and smaller alternative to DSLRs. A point-and-shoot system is just that; you point it at something and shoot.

There are of course advantages and disadvantages that come with these systems. For one, they have a smaller sensor and a fixed lens. The sensor itself is cropped further than the crop DSLR sensor; usually at 2x.

This means you are now capturing a scene 2x closer than you would if you were using the same lens on a full-frame DSLR. The benefit with the point and shoot systems is that you can now get closer to your subject.

How is that helpful? It gets you closer to celestial objects in the night sky. Or it gets you closer to that creepy crawly you want to photograph.

In Astrophotography and Macro Photography, the P&S systems are worth their salt.

An electronic viewfinder is common on P&S systems. DSLRs have optical viewfinders.

The benefit I find is in street, documentary or event photography. It means the camera doesn’t have to be stuck to your eye.

Newer DSLRs have movable LCD screens that allow you to do this, but you still lose out on the size of your device. A small camera allows you to take better candid images than a bigger one.

DSLRs require you to master each button and function. A P&S is ready to go from opening the packaging.

They are also cheaper, and some will even shoot in RAW format, such as the Ricoh GR II Digital Camera.

A diagram showing the internal workings of a DSLR camera

DSLR Vs. Mirrorless

DSLR cameras may one day become a thing of the past. Twin-lens reflexes made way for their single-lens younger siblings. New systems are being researched and developed constantly.

One advancement in photographic technology has already created mirrorless systems. These are beneficial as there is no mirror action. This mirror flicking adds camera shake. Without it, we can take faster, quieter and better photographs.

These mirrorless cameras have resolutions that are quickly becoming comparable to DSLR cameras. They are lighter, more compact and have many lens options. Perfect for any kind of photographic need, from street to time-lapse photography.

For more information on mirrorless systems vs. DSLR cameras – read our article here.

If you want to learn more about camera modes (including aperture priority mode, manual mode, and shutter priority mode) and autofocus, check out this article on Understanding Your First DSLR Camera

Do you have a new camera you’ve been dying to start using? Are you a little lost when it comes to camera settings and metering modes?

Do the words exposure compensation, f-stop and ISO setting mean nothing to you? How about white balance, low light photography, and shallow depth of field?

Check out our articles and take control of that new DSLR! 

Before you go, check out this video.

A note from Josh, ExpertPhotography's Photographer-In-Chief:

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Craig Hull

Craig is a photographer currently based in Budapest. His favourite photographic areas are street and documentary photography. Show him a darkroom and he'll be happy there for days. As long as there are music and snacks. Find him at and Instagram/craighullphoto

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