Mapping the planes

Samsung has a patent and a plan for using two lenses with triangulation (image offset) depth detection between two images in what is roughly a stereo pair. Here’s a link:

Pentax also have a system on the new Q range which takes more than one exposure, changes the focus point between them, and uses this to evaluate the focus map and create bokeh-like effects. Or so the pre-launch claims for this system indicate, though the process is not described. It’s almost certain to be a rapid multishot method, and it could equally well involve blending a sharp image with a defocused one.

In theory, the sweep panorama function of Sony and some other cameras can be used to do exactly the same thing – instead of creating a 3D 16:9 shot it could create a depth mapped focus effect in a single shot. 3D is possible with sweep pans by simply taking two frames from the multi-shot pan separated by a certain amount, so the lens positions for the frames are separated enough to be stereographic. 3D ‘moving’ pans (scrolling on the TV screen) can be compared to delaying the playback of the left eye view and shifting the position of subject detail to match the right. But like 16:9 pans, they are just two JPEGs.

All these methods including the Samsung concept can do something else which is not yet common – they can alter any other parameter, not just focus blur. They could for example change the colour balance or saturation so that the focused subject stands out against a monochrome scene, or so the background to a shot is made darker or lighter than the focused plane, or warmer in tone or cooler – etc. Blur is just a filter, in digital image terms. Think of all the filters available from watercolour or scraperboard effects to noise reduction, sharpening, blurring, tone mapping, masking – digital camera makers have already shown that the processors in their tiny cameras can handle such things pretty well.

Once a depth map exists there’s almost no limit to the manipulation possible. Samsung only scratches the surface by proposing this is used for the esoteric and popular bokeh enhancement (a peculiarly Japanese obsession which ended up going viral and infecting the entire world of images). I can easily image a distance-mapped filter turning your background scene into a Monet or a van Gogh, while applying a portrait skin smoothing process to your subjects.

Any camera with two lenses in stereo configuration should also, in theory, be able to focus using a completely different method to existing off-sensor AF – using the two lenses exactly like a rangefinder with two windows. So far this has not been implemented.

Way back – 40 years ago – I devised a rangefinder optical design under which you can see nothing at all at the focus point unless the lens was correctly focused. It works well enough for a single spot, the image detail being the usual double coincident effect when widely out of focus, but blacking out when nearly in focus and suddenly becoming visible only when focus is perfect. I had the idea of making a chequerboard pattern covering an entire image, so that the viewfinder would reveal the focused subject and blank out the rest of the scene, but a little work with a pencil and paper quickly shows why it wouldn’t work like that. The subject plane would have integrity, other planes would not all black out, they’d create an interestingly chaotic mess with phase-related black holes.

Samsung’s concept, in contrast, could isolate the subject entirely – almost as effectively as green screen techniques. It would be able to map the outline of a foreground subject like a newsreader by distance, instead of relying on the colour matte effect of green or blue screen technology. This would free film makers and TV studios from the restraints of chroma-keyed matting (not that you really want the newsreader wearing a green tie).

The sensitivity of the masking could be controlled by detecting the degree of matched image detail offset and its direction (the basic principle of stereographic 3D) – or perhaps more easily by detecting exactly coincident detail, in the focused plane. Photoshop’s snap-to for layers works by detecting a match and so do the stitching functions used for sweep and multi shot in-camera panorama assembly. Snap-to alignment of image data is a very mature function.

Just when you think digital photography has rung all the bells and blown all the whistles, the tones of an approaching caliope can be heard rolling down the river…

– David Kilpatrick


Nikon D3X announced at last!

RRP: £5499.99 / €7728.00
Availability: Late December 2008

Nikon UK is pleased to introduce its new top-of-the-range premium D-SLR – the D3X. Building on the reliability, handling and durability of the award-winning D3, the D3X offers an imaging sensor with over twice the resolution* of the revolutionary D3, breaking new ground in image quality.

(*Nikon’s own words – actually, it’s twice the pixel count, and approximately 1.42 times the linear resolution, as resolution is normally understood, though the visual information density is more than doubled).

The all-new 24.5MP CMOS* sensor makes the new model eminently suitable for the broadest range of shooting situations, both in the studio and on location – ideal for photographers seeking unrivalled detail.

(*Nikon’s own words again – we must wait to find out whether it is really all-new, or is a derivative of the Sony 24.x megapixel sensor. See features below of gapless microlens array and 12-channel readout, which are not claimed by Sony. Samsung pioneered gapless microlenses in the 14.6 megapixel sensor for the Pentax K20D/Samsung GX20).

“This is the camera that many professional photographers have been waiting for,” said Robert Cristina, Professional Products and NPS Manager at Nikon Europe. “Just as the D3 has become the professionals’ camera of choice in sports photography, the D3X’s extremely high imaging resolution will raise the bar for commercial, fashion and stock photography. The results speak for themselves: this is without doubt our highest-quality camera to date.”

The World is Your Studio

The D3X boasts a specially-developed FX-format CMOS image sensor with 12-channel readout, gapless micro lens array and on-chip noise reduction. It delivers class-leading levels of continuous shooting speed and noise management at higher sensitivities without sacrificing detail.

The D3X supports a broad ISO range from ISO 100-1600, extendable down to ISO 50 and up to 6400 equivalent with up to 5 fps continuous shooting at full resolution, or 7 fps in the 10MP DX-crop mode. The acclaimed MultiCAM3500FX 51-point autofocus system enables extreme accuracy with outstanding dynamic tracking for fast moving subjects in low light.

The camera’s LiveView function offers a smooth workflow option, perfect for studio work or other situations where the use of the viewfinder is impractical. The camera also delivers a superb response rate, with a start-up of just 12 milliseconds and 40ms shutter lag. The Kevlar/carbon fibre composite shutter has been designed for intensive professional needs and tested to 300,000 cycles.

Images with the X factor

The D3X reaps the benefits of the very latest developments in sensor design and image processing technology. Designed to produce files suitable to meet the demands of tomorrow’s commercial and stock requirements, the camera produces 50MB 14-bit NEF (Raw) files. Using Capture NX2 software, NEF files can be processed into medium format terrain; 140MB (16-bit TIFF-RGB). Fine details are reproduced with incredible clarity, whilst shadows and highlights contain tonal gradation with minimal clipping for pictures with a unique look and feel.

Intuitive control

The D3X shares the same ergonomics and handling as the D3, which have been designed to enable anyone to get to work quickly and efficiently. The bright, uncluttered viewfinder features 100% coverage and comprehensive illuminated displays, while the high-definition, 3-inch, 920,000-dot VGA TFT monitor enables outstanding playback quality for on-the-spot image assessment. The D3X’s magnesium body, which is sealed for moisture and dust resistance, also supports Nikon’s wireless system (the WT-4), HDMI output, offers a dual slot for CF cards and is compatible with the new GP-1 GPS unit.