Digital camera buying guide [Part II]: What a D-SLR can offer

by Paul Goodchild on February 24, 2009

In the previous article I touched upon the 2 main extremes of digital cameras, namely SLRs, and compacts.  The former is bulky and expensive, while the latter is small, slim and cheap.

What is a D-SLR and why would I want one?

SLR is an acronym for Single Lens Reflex.  This represents the mirror and prism system used to show the photographer exactly what will be snapped by the camera sensor when you click.  What you see is what you will get, in terms of composition.  Exposure and colour don’t apply here, though focus and sharpness do – it is physically the actual light that will hit the sensor.  This differs from non-SLRs and compact cameras in that the path of light to the camera sensor and the viewfinder are separate and therefore the image you see before taking the shot isn’t a wholly true and accurate representation of what will be.  It’s not far off generally, but it’s not the same.

What difference does that make?  For many, not a lot.  For those that demand complete control over the composition and a say in the optimal focus of the final image, an SLR is a necessity.  Many other considerations come into play with the SLR systems including the quality of the lens used to take the photos, additional flash devices and accessories, image quality and post-production options.

By far and away, for me at least, the most significant part of the digital SLR system is the image quality attainable over compact.  The sensor technology used in these devices is far superior, while the lenses used in conjunction with them will also be far more optically advanced than the typically plastic lenses found elsewhere.  When you want high quality image to either blow-up large, or to meet professional work requirements it is to the D-SLR you will need to look.  The downside, of course, is price. Or, it used to be…

The major producers of D-SLRs now have consumer entry-level offerings that are priced in and around the upper price range for compacts.  They offer you the opportunity to enjoy a photography experience approaching that of the ‘professionals’ with fantastic image quality, without the need for you to spend too much money, offsetting the risk of a large investment only to realise later that perhaps a compact camera is all you really needed.

Image quality

I will touch on this aspect a bit more to illustrate what I mean about the image quality being superior on a D-SLR system when compared with a compact camera.

One area that is most easily illustrated is the ‘noise’ present on all digital photographs.  In order to emulate the sensitivity grades of traditional film photography, such as ISO 100, 200, 400 etc., digital cameras also provide such steppings.  Unlike film, you don’t change the sensor, but just make it more or less sensitive to exposure.  This is fine in principle, but it introduces problems at higher sensitivities making some photos unusable in certain cameras due to the digital noise introduced that impacts the final image.  The sensor in a D-SLR is generally of a higher quality than compact cameras and this quality varies greatly even within D-SLRs brands.  It means that for given ISO sensitivity digital noise is less on D-SLRs.  Noise is caused by several factors, such as heat and background “electrical noise” that may interfere with the photosites (pixels) on the sensor and cause erroneous “exposures”.  This topic demands a whole post in and of itself but if you desire to understand more, please refer to the links below.

What does noise look like?  It causes grainy, rough looking photos, making normally homogeneous subjects appear to made up of noticeable speckles and artifacts that weren’t present when the photo was initially taken.  These will be especially noticeable in images taken in poorly lit environments since it is in these compositions that either or both shutter speed is decreased and ISO sensitivity is increased to compensate.  Please review the links below for further reading.

After all is said and done

When purchasing a digital camera, you will want to go for the best performing device you can justify in view of your budget and your ultimate photography goals.  Taking the route of D-SLR will afford you flexibility in lens selections while also giving you a solid base camera that will deliver higher quality photos even under difficult environments such as low-lighting.  They are bigger, usually more expensive and demand a greater investment of your time to learn to navigate the controls and bring out the best of what the device can deliver.


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