Do you remember the first Motorola mobile phones, those that were as large as a brick, and weighed as much?  It would begin a revolution that changed the way we communicate and interact with each other, ushering in an epoch of SMS, MMS, 3G wireless, mobile e-mail and a host of other technologies.

However, that was not how it began. 

It began with tiny monochrome LCD screens that displayed pixelated text, with battery life that could not last a day without charging,  with barely more than a phone number contact list as an application.  But millions bought it and it changed the world forever.  The sheer overwhelming power and convenience of mobile telephony masked all the rough edges of those early years and allowed technology precious time, time it used to fix the flaws and mature the platform.

Well, we now repeat this same story with digital photography.  Digital photography for the masses is younger than mobile phones, and it also has its ugly gaping flaws.  Haunted by its limitations, we await technology to keep improving this medium, for without doubt, it too has changed the world forever.

Understanding that digital imaging was flawed was a significantly illuminating fact for me, one that I encountered very early in my Photoshop-induced self flagellation.  The first inescapable fact that I realised was that the inherent flaws of digital were one of the key factors that makes an image look digital.  Thus, the logic was mind-boggling simple.  To make the best possible analog image, we had to first overcome the inherent flaws of digital capture.  We had to defeat the digital demons within.

The demons are many, ranging from moire, shadow transition, colour gamut issues to the limitations of the Bayer sensor pattern that is the heart of most digital capture.  However, the biggest demons of them all consumed my initial attention.  Their names are Noise and Softness.

We can get deeply technical about digital noise.  We can explore the causes of luminance and chromatic noise, seek to understand the physics behind the CCD or CMOS sensor and enter the realm of signal to noise ratios and electrical signal transmission.  I did crawl up this arduous path but it would be macho-istic of me to suggest that this was the necessary path.  What is most important is recognising the fact that naturally occurring digital noise (NODN) is a flaw.  A flaw that needs to be fixed.  The world of digital imaging knows this and there are excellent third party tools to augment the basic noise reduction algorithms of Photoshop.

BANG!

I just shot the guy who suggested that NODN is like film grain, that it can be used to our advantage.  Horse shit.  Photographers born and bred in the the era of film know that the grain of Tri-X is nothing like digital noise, that even the golfball sized grains of ISO 3200 film is a universe removed from NODN.  Yes, expensive plug-ins use crafty manipulation of artificially created noise to mimic film grain.  This is not NODN.  There is no control of NODN in the camera, you cannot predict with any degree of certainty what your noise is going to look like.  What is luminance and chromatic noise?  It is like tossing a handful of rainbow-coloured candy rice sprinkles on a piece of black canvas.  Real life does not have this effect.  Film does not have this effect.  The presence of NODN equals a digital image, a distinct DNA fingerprint of a digital cancer that robs an image of its analog life.  It does not matter how you wish to slay this demon, if you desire to use on-board camera NR algorithms, low ISOs, bigger sensors, Noise Ninjatm etc, but slay this demon you must.  The better your sword, the more sophisticated your fighting style, the closer to analog your image will become!

Digitally captured images are inherently soft.  The limitations of the sensor technology makes it so.  It is further worsened in consumer cameras by the addition of a filter in front of the sensor to combat moire.  Do not be fooled by the seemingly sharp preview images on your camera’s LCD screen.  Those are all post processed JPEG preview images, not the native RAW files.  Take heart.  You do not need to climb the highest mountain nor meditate under the coldest waterfall to discover the mystic truth about digital softness and its attendant sharpening strategies.  If you are to read only one book in your whole life on digital image sharpening,  then this is the one.

Real World Image Sharpening with Adobe Photoshop CS2 by Bruce Fraser.  Peachpit Press. ISBN 0-321-44991-6

Err...CS2?  Are we not at CS5?  This pioneer of the digital frontier sadly left us in 2006, having penned the preface for this book a mere six months prior, and we are all poorer for it.  Without doubt, his insightful work remains a fundamental bedrock that all current sharpening strategies are based on. 

Read the book.  Nuff said.

Postscript: A newer edition has since been released in 2009 called Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom (2nd Edition), Peachpit Press, ISBN 0-321-63755-0.

Postscript 2:  The Demonic List - a list of the issues in digital capture that may affect image quality.  I do not go into any detail here as millions of words have been written on these issues on the internet.  Google cum Wiki are your best friends.:)

a.  Noise - both chromatic and luminance.

b.  Image softness.

c.  Moire

d.  Lens cast.

e.  Colour depth (or the lack thereof if you are anywhere short of 16 bits.  I have never yet seen capture above 16 bit colour depth so I have no idea if my eyes can perceive that greater difference, or if it affects the analog quality of an image.)

f.  Colour interpolation as a requirement of the sensor Bayer pattern (this is a known recognised issue from day one digital capture but I am not sure if it materially affects final output.  The only sensors in the world not to have this issue are the Foveon sensors and I cannot honestly say that it is better than the standard Bayer CCD/CMOS sensors.

g.  Posterisation in shadow transition areas (this is related to colour bit depth issues).

h.  The anti-aliasing filter (related to camera manufacturers trying to defeat moire.)

i.  Long exposure limitations.

j.  Highlight hard clipping (the R255 G255 B255 wall.)

k. Resolution limitations with very large enlargements.

l. Sensors designed with Microlens arrays (majority but not all are).

m.  IR (infra-red) sensitivity and the IR filter (this was not thought to be a problem until the Leica M8 showed how it could become a problem.)