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Understanding Digital Cameras

dslr camera

Understanding digital cameras is important for anyone looking to get the most out of photography.

A solid grasp of some basic digital camera facts will help you to make the right choice when buying one and take more control when using it. There's nothing complicated you need to know, in spite of the photography world's prediliction for jargon and abbreviations!

So whether you're choosing a DSLR camera for the first time or recapping on the essentials, this should be a useful summary...


Basic digital camera facts - what is a DSLR camera?

DSLR's have been about commercially since 1991, with Kodak's DCS - 100 (the names haven't got any friendlier). Since then, they have come to dominate the world of photography, matching convenience with increasing image quality.

'DSLR' stands for 'digital single-lens reflex'. Sounds horribly complicated - but don't worry - it's really not. 'Digital' simply means that huge numbers of images can be stored on a tiny piece of kit like a memory card. They can be viewed immediately on a screen, deleted, or sometimes even edited all in the camera.

The 'image sensor', which captures light as it enters the camera, does so electronically rather than through the old chemical process of film.

'Single lens reflex'? This just refers to the 'reflex mirror' inside DSLR's. It sits at a 45 degree angle, reflecting light from the lens up to the viewfinder which you peer through when setting up a shot.

When you've lined everything up and click the shutter button, the reflex mirror swings up, making way for the light to pour in and fall straight on to that electronic image sensor, which creates your photograph.

Understanding digital cameras - What is a Megapixel?

You might already have been spattered with techno-babble by a camera salesperson on the subject of megapixels! But just what is a megapixel!? Well, as is often the case, a complex sounding word has a really simple origin - 'pixels' is just a shortening of 'picture elements'. These are the little bits, or elements, that make up a picture. They are located on the image sensor and absorb light to form a photograph.

Ok, so what is a megapixel? It's 1 million pixels. It's easier to talk in small numbers and so that's the measurement that gets used.

How are megapixels important for understanding digital cameras? As you would imagine, the more 'picture elements' the more detail in the picture. So the more megapixels the better, right? Well yes pretty much. Image quality will be better with more pixels and you will be able to print your photos to a larger size. But...

The quality of the lens you are using has a significant impact on the clarity of your shots as well. So the best DSLR camera lenses will enable you to produce better pictures.

Plus, don't be fooled by the often higher number of pixels in the best compact digital cameras to certain DSLR's. DSLR camera sensors are physically larger, and that results in greater picture detail. So a 10 MP compact camera will not outperform a 5 MP DSLR in image quality. It's a little irritating, I know, but nothing too confusing.

Those great big square cameras that you sometimes see pros using are simply built larger to accommodate a bigger image sensor which will be able to produce incredible picture detail. They are known as full-frame DSLR cameras.


Megapixels and print size

Should everyone try and get a camera with as many MP's as possible? No. Choosing a digital camera should be based on your own requirements. If you are mainly going to print 6" x 4" prints, it would be a little extravagant to go for the best DSLR camera on the market with dozens of Megapixels! Even the incredibly high quality of images from such cameras would be tricky to discern at a small print size.

For 6" x 4" prints, a 3MP camera would suffice and do a great job. For printing on A4 sheets, you would need a 5 or 6MP camera to produce photos that would look good on the wall, such as the Nikon D40. Higher numbers than these and you can begin printing small posters.

So whilst MP's are an important factor when choosing a DSLR camera, it's worth knowing what a sufficient amount would be for your purposes, and taking into account other considerations as well.

Understanding digital cameras - Compact v DSLR

dslr v compactWhat makes DSLR's so different from those little compact digicams everyone has? Well, both are great for their own purposes. The best compact digital cameras can produce excellent images, and are conveniently portable. But DSLR's have a lot to offer...


  1. DSLR's are physically much bigger than compact cameras, but this allows them to contain considerably larger image sensors, which produce far higher quality photos.

    Compact camera image sensors are typically only about 3 to 5% the size of the largest sensors in the best SLR digital cameras (although the majority of DSLR sensors are about 40% the size of the largest). So there is a much greater potential range of print sizes with a DSLR camera.

  2. With DSLR cameras you can use any number of different, detachable lenses. They click on and off really simply, and give you loads more options. For example, if you love wildlife or sport you can get right into the action with a telephoto (big zoom) lens attached to a DSLR camera.

    Warning! When looking for the best compact camera always go for one with an 'optical zoom', not a 'digital zoom'. The latter amounts to a simple crop, which reduces the image quality of the remaining portion. This is an important distinction for understanding digital cameras.

  3. The zoom on DSLR lenses in turn provides greater freedom over the aperture and shutter speed settings. This opens up possibilities for experimenting with depth of field and the appearance of motion.
  4. The double clicking sound made by DSLR cameras as you press the shutter button is really satisfying!


Who makes the best SLR digital cameras?

Most people use either Nikon DSLR cameras or Canon DSLR cameras These 2 companies have great reputations and together control at least 80% of the market. They are followed by Pentax, Olympus and Sony as the next most popular. All 5 companies are Japanese. The German company Leica and Swedish company Hasselblad are also well known producing some of the best SLR digital cameras.

The Photography Crash Course: 17 Short Lessons To Camera Mastery

Where Next?

Online Digital Photography Courses

Digital Photography Magazines

Canon Camera Reviews

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