What is a DSLR Camera in Photography – Everything you need to know!

For many people, the decision to buy a DSLR camera is the point where they start to take their photography a little bit more seriously.

In this article, I’m going to tell you first of all what a DSLR camera is in photography terms, followed by the reasons you might want to consider purchasing one, as well as other alternatives.

I will also take you through some of the jargon you are likely to encounter as well as the advantages (and disadvantages) of one of these cameras.

I will be focusing this article from the perspective of an upgrade from a standard point and shoot digital camera or smartphone to a DSLR camera. I’ll also compare and contrast DSLR cameras to mirrorless cameras, which are a popular option these days.

If you are interested in buying a camera of any kind, I also suggest checking out my detailed article on picking the right camera. I also have a beginner’s guide to DSLR cameras, which should help you get the most out of one if you are new to this type of camera.

First of all then, what exactly is a DSLR camera, and what is the difference between it and a standard point and shoot?

What is a DSLR Camera?

A DSLR camera is a digital single lens reflex camera. What this means is that inside the camera there is a mirror and prism system which passes the light from the lens to the viewfinder.

This differs from other camera designs, where either a separate lens is used for the viewfinder (often found on point and shoot cameras), or the image is viewed on a digital screen directly from the sensor (point and shoot cameras, mirrorless cameras or smartphones).

This mirror and prism system is the key design feature which separates a DSLR from other types of camera system.

A mirrorless camera is different from a DSLR because as the name suggests, it doesn’t have the mirror. This is the same as a point and shoot or a smartphone.

The result is the same – you don’t get that optical viewfinder, and images have to be seen after passing through the camera sensor and appearing on either the screen on the back of the camera, or on a screen in the eyepiece.

There are a number of other features that you will find on an SLR and not on a point and shoot or smartphone, which we will look at in the next section. First though, you might also be wondering:

 

What is the difference between a DSLR and an SLR Camera?

A DSLR is the modern replacement to the traditional SLR camera. The key difference is that a DSLR uses an electronic sensor to record the image data, whereas an SLR camera used a roll of light sensitive film.

 

What is the difference between a DSLR Camera and a Point and Shoot, Mirrorless or Smartphone Camera?

1. Sensor Size

One of the reasons people want to upgrade from a point and shoot digital camera to a digital SLR is the improved image quality. A key factor in this improved image quality is the increased size of the sensor that a DSLR has compared to a point and shoot camera.

The sensor, for those not in the know, is the thing inside a digital camera that records the light information. Once upon a time, the light information was captured by film, of the 35mm variety. These days, digital is the way forward, and the camera contains a digital sensor for this purpose.

Sunset over Mount Ruapehu, Tongariro National Park. The larger sensor sizes in a DSLR camera are more flexible in limited light scenarios.

The size of the sensor is directly related to the quality of the image, influencing factors including how noisy the image is and how well the camera performs in limited light scenarios.

When I talk about the size of the sensor, I am referring to the physical size of the sensor itself, not how many pixels the sensor is capable of recording. Beyond a certain number, the number of pixels becomes largely a handy bit of marketing rather than anything meaningful to image quality. Sensor size is far more important than megapixel count.

Sensor size is, to confuse matters, not set to one size for point and shoot cameras, one size for mirrorless cameras and one size for DSLR cameras, but as a rule of thumb, cameras fall into one of three categories:

• “Full frame” (or APS-H) sensors are found on more expensive, professional grade DSLR cameras and mirrorless cameras. These sensors are physically around 35mm wide – the same size in fact as a piece of 35mm film. Hence the term, full frame.
• APS-C size sensors are found on the majority of consumer oriented digital SLR cameras and many mirrorless cameras. These feature a sensor which is 22mm wide, resulting in a total sensor area which is about 40% that of the full frame sensor. Some more recently launched mirrorless cameras also feature this size of sensor – making them a great alternative.
• 1/2.5” sensors are found on most point and shoot cameras. These sensors really are tiny – only around 3% of the full frame sensor area. Hence the difference in image quality.

 

2. Interchangeable lenses

After sensors, I will now move on to lenses. Interchangeable lenses are an excellent reason to get a DSLR or mirrorless camera, both of which support changing the lens.

Depending on the type of photography you want do do, you can switch lenses from something that lets you take in really large panoramas (a wide angle lens) to something that lets you get up close and personal (a telephoto lens).

As with sensors, there is a world of jargon that you need to know about, particularly when coming from the point and shoot world.

Your point and shoot camera will have one lens option, which will usually be capable of optically zooming. It will have an optical zoom rating, normally provided, nice and simply, as a multiple. So if you have a camera with a 3x zoom lens, you know that you can point at a subject and make them appear three times larger. Easy.

DSLRs do not adhere to this handy standard. Instead lenses are categorised according to two parameters: aperture and focal length.

 

Focal length

Focal length, which is measured in millimetres, will usually be the first thing that is considered when choosing a lens, as it is this that dictates the magnification of the subject you are photographing. This is rather similar to a point and shoot optical zoom rating.

Unfortunately, focal length does not easily convert to magnification factor, for a number of reasons, the main one being that different cameras have different sensor sizes. A 50mm lens on a full frame sensor camera would result in a different image if it were put on an APS-C sensor camera, for example.

On the whole however, and without getting too technical, the smaller the number in mm, the wider the resulting image will be, and the bigger the number in mm, the more magnification. To be considered wide angle a lens would usually have a focal length of around 28mm and down, whilst a telephoto lens would be 100mm and up.

The above two shots demonstrate the different focal lengths available on a 17-85mm lens. The first is a wide angle shot taken at the lenses maximum wide-angle setting of 17mm (35mm equivalent 28mm), whilst the second is taken with the lens fully extended to its maximum focal length of 85mm (35mm equivalent 138mm). This variety of magnification factors is a real benefit of a “zoom” lens.

As a note of reference, when comparing lenses and images, it is not unusual to refer to the “35mm equivalent focal length” of an image. This allows for a standard to be used for focal lengths across cameras with different size sensors. In the shots above for example, I am using an APS-C sensor – to achieve the same magnification on a full frame body, I would need to have a lens with a focal length as indicated in the brackets.

For those of you interested in these things, the mm value refers to the length the lens would have to be, in millimetres, if it was composed of only one piece of lens material. These days lenses are made up of multiple elements, thus reducing the physical size.

When it comes to focal length, lenses fall into one of two categories. A prime lens is one with a fixed focal length, say 50mm, whereas a zoom lens can vary its focal length.

A prime lens will usually have greater image quality with the trade off that you need to carry more lenses to cover your required focal lengths, whilst a zoom lens can result in image flaws at the benefit of being better as an all purpose lens for multiple tasks.

 

Aperture

The other factor to consider when purchasing a lens is the aperture. The aperture is the hole inside the lens that opens up to let light in – to use a well worn metaphor, it is much like the iris of an eye. The bigger the hole, the more light that goes in, the smaller the hole, the less light that will go in.

Outback sunset, Australia. This was taken at the maximum zoom of this lens with the aperture as wide open as it would go for that zoom length, which was a not very wide f5.6. A telephoto lens will usually have different maximum aperture ratings for different focal lengths.

I have a far more detailed post on how aperture and shutter speed work together when shooting, and how they affect the resulting look of the final image.

From a purchasing perspective, usually the bigger the aperture, the better and more expensive the lens. A bigger aperture means more light can get in, which means you can work at higher shutter speeds and in lower light conditions. You may seem people referring to a lens as being “fast”; what this means is that it has a nice big aperture. Conversely a “slow” lens will have a relatively large minimum aperture.

Aperture is measured by “f” stop, with numbers ranging from around 1.x up to around 32. The smaller the number, the bigger the hole. The majority of telephoto style lenses have a variable aperture, which changes as you change the zoom length.

For more on cameras lenses and what to look out for, see my guide to the best cameras lenses for travel photography.

 

3. Camera size

That was focal lengths and apertures. You can pretty much breathe easily now, because we are over the hard parts!

A clear difference between a point and shoot and a DSLR is size. All that lens, mirror, prism and enlarged sensor have to go somewhere, with the end result that the bit of camera you are lugging around is no longer going to slip handily into your pocket.

This may seem pretty obvious, but is worth bearing in mind.

One of the reasons that many people opt for a mirrorless camera over a DSLR camera is that a mirrorless camera offers many of the positive aspects of a DSLR (sensor size, image quality and interchangeable lenses) whilst being in a smaller form factor.

 

4. Speed

Speed is another serious advantage that a digital SLR has over the majority of point and shoot cameras.

Because the camera is not caught up with trying to populate the LCD screen on the back of your point and shoot with everything that is going on around you, the time from pressing the button to recording the picture is not plagued by what point and shoot owners would refer to as “shutter lag”.

Instead, when you press the button, you pretty much get the picture taken at that moment in time. So you are less likely to miss a key moment. Great news, particularly for sports or action photography enthusiasts.

That said, there are some excellent point and shoot cameras available today which do not have these issues. See our guide to the best point and shoot cameras for some ideas. Mirrorless camera technology has also advanced to the point where this is also not an issue.

 

5. Setting control

Whilst some point and shoot cameras do give you more options in terms of controlling various settings of the camera’s features, they usually don’t come close to what you can do with a DSLR or mirrorless camera.

On a DSLR or mirrorless camera, pretty much everything can be adjusted, from aperture, to shutter speed to focal point, giving you seriously fine grained control over your images.

 

Is a DSLR better than other types of camera?

Having now waxed on about the wonders of the DSLR in terms of image quality and lens flexibility, I will now go through a number of reasons why a DSLR may not be right for you in certain circumstances.

 

1. If you’re travelling light or you might lose it

If you are planning on travelling light, then a DSLR could be an issue. Even if you only have the one lens, a DSLR is always going to be a more significant burden compared to a point and shoot digital camera that you can slip into your pocket.

As well as this, a DSLR is not the best for many situations where we want to document our fun times in an easy and portable manner, for example, on a night out.

Rocking out in a nightclub or at a beach party with a DSLR slung around your neck is hardly a practical option compared to the pocket-able point and shoot option, and the risk that you put it down somewhere and it vanishes of it’s own accord is not one you are likely going to want to take.

In situations like this, I’d either a mirrorless camera or high end point and shoot camera.

Take a look at our travel camera guide to for camera recommendations for a variety of situations, as well as our recommendations for the best point and shoot cameras, and best mirrorless cameras.

 

2. If you need to be inconspicuous

Let’s face it, there is no way you can be subtle with a DSLR. Even if you decide to shoot “from the hip”, the noise a digital SLR makes, what with the mirror flipping up and the shutter opening and closing, is incredibly distinctive.

So if you need to take photos without being obvious about it, a DSLR is not likely to be the best option. Instead, again, consider a mirrorless camera or good point and shoot camera.

A self portrait in a series of mirrors in a bar in Cologne. Usually, a DSLR isn’t the best choice for a night out!

 

3. If you need something rugged

Most electronic devices are susceptible to the rough and tumble of everyday life, but cameras, featuring delicate bits of glass on top of the electrical wizardry, are particularly prone to damage.

DSLRs, with their protruding lenses, do not take to being dropped very well, nor are they great at handling the elements, unless you go for the expensive weather sealed professional level cameras.

On the other hand, you can pick up waterproof and shock proof “ruggedised” point and shoot cameras for little more than their standard variants. So if you want to be able to shoot underwater or you regularly bounce your camera off concrete, you may want to consider one of these instead.

Water exploding on the Western Australian coastline. Keeping my SLR dry in these sorts of conditions can be a bit of a challenge.

4. If budget is a key consideration

A DSLR camera is generally one of the more expensive types of camera available, although of course, this varies. Entry level DSLR cameras are available at a much lower price point than high end compact cameras for example.

However, if you are shopping for an inexpensive camera, a DSLR or mirrorless camera might not be the best pick. An entry level DSLR camera will generally cost in the region of $400 – $500 with a lens. An entry level mirrorless camera is likely to be slightly more expensive than that, generally around $500 – $600.

Consider that you can get a reasonable entry level point and shoot camera for around $200, and you can see there is a clear price difference. As you go up in features and capabilities, and especially when you factor in a quality lens or two, and high end DSLR or mirrorless camera systems can easily set you back thousands of dollars.

 

DSLR Camera Brands to Consider

There are a number of digital SLR manufacturers, but most people will find themselves choosing between the two major players in the space – Canon and Nikon, who between them account for over 80% of worldwide digital SLR sales.

The choice between the two manufacturers largely comes down to personal preference and what feels better in your hand. Both companies manufacture excellent products, and both have a wide range of lenses to suit your needs. A couple of notes on their ranges:

 

Canon

Canon’s digital SLR range is ordered by number, ranging from the 1000D through to the 1D. The D stands for digital. The less digits there are in the model number, the higher up in the range they are, with new models in each bracket receiving a higher model number.

So for example, the 70D is a model range above the 700D, and the 750D is the successor to the 700D. Generally speaking, the three and four digit models are aimed at consumers and hobbyists, with the more expensive one and two digit models aimed at professionals. With the exception of the 7D, all of the single digit models are full frame.

 

Nikon

Much like Canon, Nikon’s range is denoted by number, although the numbering system is slightly less simple to decipher. There are basically four numbering ranges, from the single digit professional level cameras like the D3, to the four digit entry level cameras, like the D3000. After that it starts to get a bit complicated, with the D700 for example being a professional grade full frame sensor option, and the D70 – D90 models being the equivalent to Canon’s 400D – 550D range.

I have no idea why model numbers in the technology world are quite so confusing (Intel’s processor range is my favourite example of this), but luckily there are oodles of photography sites out there who can explain these things to you in more detail.

 

What About Mirrorless Cameras?

A mirrorless camera is, for many, the perfect trade-off between a point and shoot and a DSLR. They offer the advantages of a DSLR, including full manual controls, large sensors and interchangeable lenses, whilst coming in a smaller form factor.

Many photographers have made the switch, and the technology improves every year. Generally, I recommend mirrorless cameras in most cases nowadays – check out my guide to picking a travel camera for tips on the best models right now, as well as our detailed guide to mirrorless travel cameras.

The only downside to mirrorless cameras is that they are still relatively expensive, and at the entry to mid range level in particular, DSLR cameras are still often better value.

 

Choosing a lens for your DSLR camera

The camera body is clearly an important consideration, but of far more importance when purchasing your DSLR is the lens. It is not uncommon, in fact, to spend more on the lens than the camera body.

When you are starting out, you may find that you will have the option to purchase what is known as a “kit” lens with your camera. This is usually a relatively cheap lens that will get the job done, and let you get to grips with your camera, but you will ultimately end up replacing it once you start getting more serious.

You can save yourself a bit of money in the  long run by opting to buy a more suitable lens from the start. See our guide to the best travel lenses to get some inspiration for your purchase.

As well as considerations like focal length and aperture, lenses come with what may seem to be a bewildering array of acronyms. Often these just refer to the focusing mechanism that the lens uses, or whether or not the lens features an Image Stabilisation technology to reduce camera shake.

Deciding on a lens is entirely a personal choice, and comes down to the sort of photography you are doing, as well, of course, as your budget. Take your time and do your research. If necessary, rent a number of lenses for a period of time and see what you think.

This is a serious investment, and needs to be treated as such. You can read more about lenses, as well as other accessories, for SLR cameras in this article, plus you can get to grips with a number of other photography related tips in the rest of this series.

 

Looking to Improve Your Photography?

If you found this post helpful, and you want to improve your photography overall, you might want to check out my online travel photography course.

Since launching the course in 2016, I’ve already helped over 2,000+ students learn how to take better photos. The course covers pretty much everything you need to know, from the basics of how a camera works, through to composition, light, and photo editing.

It also covers more advanced topics, including astrophotography, long exposure photography, flash photography and HDR photography.

You get feedback from me as you progress, access to webinars, interviews and videos, as well as exclusive membership of a facebook group where you can get feedback on your work and take part in regular challenges.

It’s available for an amazing one-off price for lifetime access, and I think you should check it out. Which you can do by clicking here.

Well, that’s about it for my take on what you need to know about when it comes to digital SLR cameras. Let me know if you have any thoughts on this article in the comments below!