Use your flash on a sunny day...

When I originally decided to start a blog, I set out to tackle two distinct themes, technology and photography. With that in mind I decided today to write a piece attending to the latter. This may turn into a series of the simple tips and tricks I've picked up over the years from my own trial and error and from some great photographers.

There have been so many innovations in photography over the last few years it's hard to keep up. Reading the specs of even the cheapest compact pocket digital camera, one would think all you needed was the ability to stand vertically, point the camera in vaguely the right direction and pow! magic happens. The reality is of course very different. What ever additions or automations appear, what ever surprising applications of digital processing arise, photography remains an art. There are, however a few basic principles and a couple of simple techniques that can turn a dull snap into a decent picture and these techniques apply what ever equipment is at hand.

Photography is about composition and exposure. Both contribute to a photo's ultimate artistic merit but exposure is also driven by technique and a tiny bit of science. On modern digital cameras, exposure control is normally a mystery, hidden by "Auto mode" and left to the supposedly superior intellect of the camera's on-board processor. In reality, that processor, or at least the exposure program it runs, isn't particularly smart.

So what is exposure? Exposure is a term that describes the level of reflected light captured by a camera in order to record an image. In most cases, "correct" exposure means an accurate representation of the scene has been captured where detail is visible in both the highlights (brightest areas) and shadows (darkest areas). In modern digital cameras exposure is controlled by the aperture setting, the shutter speed, the digital sensor sensitivity (ISO value) and, in some circumstances, the flash. At the risk of adding to much complexity, most digital cameras can actually control two different exposure values simultaneously for any given image. The second exposure is controlled by the flash.

All automatic cameras use pretty much the same exposure calculation paradigm. They all attempt to assess a scene and then set the camera's exposure control to achieve an even exposure. In this context, the rather vague and inexact term "even" actually has a numeric translation - 18% grey. An 18% grey card is a tool used by photographers down the years to check exposure. A card that is prepared 18% grey actually reflects light pretty much in the middle of the range between white and black. In other words, your camera's exposure meter aims to make your image look as close to grey as possible! In reality, an image contains a vast range of lights and darks. Your camera tries to find an exposure value that will enable all these different tones to average out at - you've guessed it - grey! So what does this mean in practice? The easiest way to explain this is an experiment. Take your camera, set it to auto and take a shot of a white piece of paper. Look at the result and you will see, instead of a fresh white sheet of paper, you'll have something that looks like it was washed with a pair of dark socks! it will be a washed out grey colour. Ok, now find something jet black, take a shot on auto and...you've guessed it, the black item appears grey and lacking in contrast. In both cases, the camera has set a combination of shutter speed and aperture that achieves a scene that averages to 18% grey. This behaviour has many implications and is the key reason why so many auto-mode snaps end up either looking uninspiring and washed out, or as if they were taken in a cave!

OK, here's the first tip - Use your Flash...
The message here is simple, use your flash when ever you can. Even during the day, in fact especially during the day. Why? You'll have heard it said many times, "never take a shot into the sun" or "always have the sun behind you". While this does provide even illumination of your subject, it also means they are probably squinting. Also, your subjects will look flat and uninteresting, all the contours and definition of their features erased by a solar blast. Finally, you can't always guarantee to have the Sun and your subject where you want them.

Now most people will have taken shots before where the subject is strongly backlit. what typically happens is you end up with a well exposed background and a subject with a featureless face shrouded in total shadow. The reason for this is pretty straightforward, the background light source is dominant, much brighter than your subject's face. The camera attempts to set an exposure that balances the brightness levels in the overall image. It sets a combination of aperture and shutter speed that reduces the amount of light recorded by the sensor to a level defined by the large bright source in the background. Unfortunately, in this situation, the relatively tiny amount of light reflected by the subject cannot compete and the subject is thrown into a dark gloomy shadow.

Now remember earlier I suggested your camera can manage two different exposures simultaneously? The flash unit (built in or external) can come to your rescue. While the camera's main exposure program sets the exposure value for the dominant background, turn on the flash and magic happens. With the flash on, press the trigger and a blindingly fast set of events take place. The camera will launch a pre-flash before the shutter is opened. The intention of the pre-flash is to test the amount of light required to correctly expose the foreground subject. The amount of light is controlled by the duration of the flash burst. Once the amount is computed, the shutter opens for the time required to correctly expose the background and, at the same time, the flash fires for the amount of time required to correctly expose the foreground subject. The end result is an image with a well exposed background and a properly exposed subject, all this happens in the blink of an eye. You see? two different exposure controls applied to a single daytime photo. There are some other desirable outcomes from using daytime flash. The flash helps the skin tones of human subjects to look warm, rich and healthy. Those unsightly shadows under the eyes and chin so typical in sunny day shots will be filled in giving a pleasing, detailed and flattering result. Finally the eyes will benefit from a catchlight, a tiny reflection of the flash pulse in each pupil. The catchlights make the subject look alive and somehow three dimensional.

Both of the images I've included in this post were taken using this technique. Each shot has a low key ambiance yet both were taken in the middle of a field on a bright sunny afternoon. In this case I have used off camera flash and a SLR but similar results could be achieved with a compact. The secret is in managing the two exposures, ambient and flash. In this case, I have reduced the dominance of the natural light by under exposing the ambient light by 1.5 to 2 f-stops. The flash is set to expose the foreground optimally (in this case I used a manual flash power setting, but you could leave the flash on its normal automatic setting and allow it to set its own optimum exposure)

As I said at the top, nearly all cameras have the ability to do this, if you're using a simple point and shoot compact camera, find the control that sets the flash to "always-on" when you're taking your next set of sunny day shots. You'll be surprised by the results and you'll wonder no longer why those frantic press photographers always use flash during the day for those "must-get" publication shots they earn their living from.

A new blogger's first week

I can't believe I'm the first to have made this mistake, I imagine I won't be the last. The whole purpose of blogging, at least in my opinion, is to provide concise, useful insights that others may find of interest. After my first posts I received positive feedback and considerable encouragement to do more. This kind of backslapping, chest pumping support leads you to the mistaken opinion you have gained your literary wings.

My third post set out to be a comprehensive missive arguing the case for the the widespread adoption of Ubuntu 9.04 as a desktop operating system. It's progressing well but there is still much work to do. I'll have it complete in the next couple of days (I hope) but that can't be guaranteed. Work comes first and represents long concentarted hours; it's tough to reset, to reengage brain and shift to something new after a long busy day.

So, what to do? Well the Ubuntu essay will get published, hopefully much sooner than later. In the interim, I think I'll try walking before I attempt to run the London Marathon!

Operating systems, a religous experience?

Opinions are funny things. They are usually strongly held beliefs, a matter of principle a point to defend when confronted with the objections and ridicule of the masses. And so it is with the almost religious fervour that accompanies Operating System discipleship.

There are the Microsoft Windowites, a huge dynasty subdivided into many sects. The '95, '98 and Millennium castes seem to have dispersed. There are reports that small pockets of this once proud following do exist, largely in the dusty halls of local authorities and government agencies. Then there are the XPites, the Vista clan and now the emergence of the number 7. Seven is considered a lucky number in many cultures and so it seems Microsoft are hoping it can bring unanimity to their disparate following, a single clarion call that all can align behind. Can they shake off the ills that plague all long standing and dominant civilisations greed, decadence and, in the case of their platform, obesity? This is unlikely but time will tell.

But wait, what of the forbidden fruit, what of the Apple? A young vibrant brand of religion this, all bright, happy and shiny. Full of big smiles, warm handshakes and cool haircuts; gone are the dowdy formal uniforms of the Windowites, you can wear your jeans around your knees, tattoo your nose and still wear the badge of the blessed fruit. Membership comes at a price. It's no easy task worshiping the Apple, the tools of the trade are highly prized and cost the Earth. You'll need a lot more than plain old gold, frankincense and Myrrh, many pieces of silver must be offered. Strangely the basis for this most modern of followings, it's foundation, it's very core, hidden by high fashion and makeup is a relic from the past, behold the Unix operating system.

Back in our history, long before the first newborn gurgle of the PC, there was Unix. Long beards, comfortable footwear and real ale defined this most ancient of followings. Yet at its heart, at the centre of its belief was the kernel. The kernel was all powerful, all knowing yet simple and forgiving. It brought order to chaos, offered forgiveness to errant applications and it just kept running. Nothing could bring the kernel down, no external force or internal conspiracy, it was omnipotent. The rise of the Windowites threatened to eliminate Unix but its core strengths and virtues, reborn under the Apple and Linux moniker, have survived. Linux, unlike Apple, promises to establish, once again, A single community, a home for everyone, free to join, and available to all. Unfortunately Linux is fragmented into many different groups. All however share a common belief, a point of connection, the Kernel binds them together.

I'm a linux believer as you may have guessed. In subsequent posts I'll try and explain why. I'll attempt to outline why the time is right to consider linux, Ubuntu in particular, as the natural choice for our desktop operating systems.

Entering the fray...

There are many things I intend to do or have intended to do. Some blossom from good ideas into real substance and purpose, others lose their way and become a forgotten good idea. My intention to establish a blog has, for some time, been a member of the latter, a good idea that somehow spent its life on the "too hard pile". Not too hard because of any technical difficulties, technical complexity is my forte (as the blog, I hope, will reveal); more because of time, distractions, commitments and host of other equally feeble excuses.

With that behind me I feel it's time to enter the fray and establish my own blog. Its purpose, structure and objectives are, at this point, a little shall we say embryonic. However I'm sure it will take shape nicely over time. I feel I have lots of information, perhaps even some knowledge and, dare I say, occasional expertise to share so here goes.

I have spent 25 years in the telecommunications business and for much of that at the forefront of new technology developments. I'm an electronics engineer by qualification but have enjoyed a significant period of my career in the development of industrial software. I'm now a kind of technology evangelist I guess. The time I've spent in the industry has enabled me to sample, study and pursue many diverse aspects of the technology multiverse we live in today. To that end, I aim to talk about some of those subjects and developments I feel may have the most impact on our lives.

I'm a big supporter of the Open Source software development initiative. I'm an even bigger supporter of the drive to make the Linux operating system mainstream and suitable for all. I'm a keen and reasonably skilled photographer and have enjoyed many years experience working with digital photographic techniques, post processing and equipment. I'm London based, a sports fan, I soak up news and current affairs like a sponge and have an unhealthy yet unbreakable addiction to Indian food. All that to say, this could be a varied mix of well structured and thoughtful observation or a ragged depository for the unintelligible ramblings of a narcissistic forty something, who knows...