Dynamic range and the various ways of trying to capture and represent it are the topic of many a heated discussion on the forums. We spoke to Apical, a company working on this challenge whose technologies are incorporated in cameras from the biggest brands, to find out what it is doing to address the matter. We think this interview with managing director Michael Tusch will help shine a little light on this shadowy corner of image processing.
Out of the shadows
You may not have heard of the British imaging technology company Apical but, if you've used a camera made in the last couple of years, there's every chance you've used technology it has developed. This is because a wide variety of cameras, from compacts through to pro-level DSLRs incorporate its processing algorithms. You may know it as D-Lighting, Shadow Adjustment Technology or Dynamic Range Optimization, but the underlying technology starts with Apical.
We visited Apical's Headquarters and spoke to its Managing Director, Michael Tusch, to find out what the company is trying to do to improve the dynamic range capabilities of digital cameras.
Dynamic range has become a hot-topic amongst the camera-owning cognoscenti, who often worry that their camera's sensor cannot capture the full range of tones from the deepest shadows to the brightest highlights in a scene. But the use of simple, whole-image, tone curves often fails to convey all of the captured dynamic range into the final image, with important detail disappearing in the shadows.
'At its most simple, what our algorithms do is called dynamic range compression - trying to render extremes of light and dark in the way that the human eye would interpret them,' he explains. As it turns out, the company's starting point was human vision, rather than digital imaging: it was originally spun-out from a research group working on modeling biological imaging systems. 'The human eye is highly adaptive to light, and is able to interpret great extremes of light and dark,' says Tusch: 'The main thrust of that work was developing algorithms that could model the human visual system and the researchers realized that some aspects of that could be applied to digital image processing.'
'Our aim is to enable digital cameras to produce the most natural image in the most natural way,' he says. 'Other people were trying to do this at the time but all the existing tools either required manual intervention or had processing demands that were unsuitable for cameras. We created a model that achieved this, was suitable for use in a digital camera and could be included in the image processing pipeline. And it did this in a highly adaptive manner, so it's not something the user had to adjust or worry about.'
From small beginnings...
Given that its system was an adaptive one, that required no intervention, it probably shouldn't come as a surprise to find that the first application of Apical's technology first appeared in compact cameras. Nikon was the first digicam customer, building its D-Lighting system on the technology, in its Coolpix range. 'By 2004 all of the Coolpix range included D-Lighting and later Olympus's Mju series started to incorporate our technologies - with their implementation called Shadow Adjustment Technology.'
'People started to realize there is more to creating a realistic-looking image than just tone-curves and demosaicing,' says Tusch. As anyone who has tried 'rescuing' an image in post-processing using curves will know; it's difficult (and often impossible), to preserve extremes of light and shade in the same image without the result looking 'flat' and unrealistic. The problem, Tusch says, is that steepening the tone curve to increase contrast in the dark part of the image means flattening the tone curve somewhere in the midtones or highlights, leading to a loss of contrast and color in those regions. 'Most tone mapping algorithms steadily reduce local contrast as the strength of dynamic range compression is increased.'
Apical attempts to get 'round this problem by assessing the local environment of each pixel and considering its relationship to its immediate neighbors as well as their context within the image as a whole. 'To give it its technical name, our product, Iridix, is a space-variant dynamic range compression algorithm. What the eye does, in camera language, is apply a different gain, based on the local environment of a pixel - for example, a pixel with a specific R,G,B value in a bright region would be interpreted very differently to a pixel with the same R,G,B value in the shadows.' Iridix aims to mimic this response: it assesses how each pixel relates to the ones around it, in order to work out the local contrast, while also working out how that region fits in with the rest of the image.
|Single adjustment curve applied||Iridix result|
|Show adjustment curve||Show Iridix local adjustments|
|Using a single, homogenous, curves adjustment to try to correct the entire image results in a slightly flat, washed-out looking image. Iridix calculates a different tone curve adjustment for each part of the image (varying slightly between each pixel), in an attempt to preserve local contrast all the way across the image, lifting the detail in the shadow regions without the whole image looking washed-out.|
'To achieve this, and ensure the image looks natural, there are four non-trivial factors that need to be considered,' explains Tusch:
- The preservation of the black and white points of the image (to prevent color clipping and avoid true blacks becoming gray)
- The preservation of true color
- The exact preservation of local contrast.
- The complete elimination of any spatial artifacts, such as halos
'Getting any of these four wrong results in a unnatural looking image. For example, if you look at tone mapping algorithms for high dynamic range imagery, they often produce rather un-natural, "painterly" images, this is simply the result of an inappropriate algorithm - the results should look completely natural.'
...to the hands of the professionals
The technology is no longer confined to compact cameras, however. 'We had faith that it would be a very useful tool for professional photographers,' says Tusch, ' if well implemented and well explained.' And to illustrate his point, he points out that the company's technology has become wide-spread in the DSLR sector, appearing in products from Sony and Olympus, amongst others. 'We've built an image engine that produces image quality suitable for professional photographers. However, we wouldn't advocate this always being enabled because you may not always want the photograph to represent the scene the way it appeared - you may wish to present a more creative interpretation.
We simply aim to achieve pictures which look as close as possible to what you see with your eyes when you take the shot. And, of course, studio photographers simply don't need such a feature because they have complete control over the lighting of their scenes. But for photographers outside or, for instance, at weddings in which not all the lighting can be controlled, we think it can be useful.'
'And we've had a very strong positive response. That's because we think the manufacturers have worked hard to work out how to apply it for a professional audience. I think [the professional photographers] realize it's not a touch-up, it's a scientifically-backed quantitative way of improving image quality and getting the result you want.'
Unsurprisingly, Tusch says there is a philosophical distinction between the two sectors: 'In compact cameras, the expectation is that the camera will capture the scene as you saw it, without you having to think about it, so it tends to be an on/off feature. I think with DSLRs there's a lot more interest in being able to control this technology in a quantitative way (although it still has a self-adapting element to it). That way, it can become a tool that, once understood, can be used by photographers to optimize their image, just as they would with any other setting.' In the same way that photographers have demanded that ISO be as easy to access and change as shutter speed or aperture, Tusch says he hopes that in the future, dynamic range compression will be a turn of a thumb-wheel away.
He also believes the technology will improve: 'We're on version 6 of our product now but we're always trying to raise the technical bar - as the processing gets faster we want to get more sophisticated in terms of the algorithms we can use. But it's not just the processing that prevents the use of more complex algorithms - there are also huge technical challenges relating to how data gets moved around inside the camera, especially as you get more megapixels.' But Tusch is confident that the manufacturers share his company's ambitions to keep improving the final results: 'We're a technology provider, we work in many different areas of imaging. It's up to the manufacturers how they want to apply our technologies but the thing we love about working with DSLR companies is that, although (like everyone else) they have strong cost pressures, they will absolutely not compromise on image quality.'
Interview by Richard Butler
Mar 15, 2012
Feb 10, 2012
Feb 25, 2012
Feb 6, 2012
|_MG_5100 by tim and jan|
from Welcome to the Saloon!
|The Grimm 11 year old by Ryan Gardner|
from Trick or Treat
|Heron with fish by APenza|
from A Big Year - birds
See some of the most iconic black-and-white photographs throughout history brought to life by a community of colorization enthusiasts and professional retouchers in the new book Retrographic.
Shopping for a photographer? Whether you are one yourself or not, chances are you could use some ideas. From stocking stuffers on up, we've got some photography gift suggestions for every budget.
We're counting down our top 10 most popular sample galleries of 2017. Drum roll please... the #6 spot belongs to none other than the Sigma 85mm F1.4 DH HSM Art.
Read the story behind this gorgeous wedding photo captured at Trolltunga in Norway by husband and wife duo Priscila Valentina Photography. The 14 hour hike in the rain that preceded this shot was TOTALLY worth it.
Go behind the scenes with filmmaker Nick Arcivos, who recently created a beautiful cinematic short film in Paris using only the iPhone X, a couple of gimbals, and a few lights. The results are very impressive.
A Bay Area startup offering a pay-by-the-photo camera service cleverly addresses the pain points photographers experience when they pick up their first DSLR. But can it survive the smartphone?
It's been a big year for software innovations, dual cameras and huge displays. Take a look at our picks for the top smartphone cameras and why we think they stand out.
We're counting down our top 10 most popular sample galleries of 2017. At the #7 spot is the ready-for-any-weather Olympus Tough TG-5.
By combining his skills as a time-lapse filmmaker and an engineer, Julian Tryba created this out-of-this-world creative 'layer-lapse' of New York City that alternates between night and day in time with the music.
Canon Japan's new lineup of novelty camera-themed gifts was just revealed online, including a lens mug and lens thermos, two retro camera-themed USB drives, and a picnic mat.
The Profoto A1 most certainly isn’t for everyone [...] But for those who are used to using the Profoto systems, and want something that pairs seamlessly with the strobes you already have, there is no better companion.
Fujifilm has asked a US district court to clear it of any wrongdoing, after allegedly being threatened with trademark litigation by Polaroid.
While a couple of our reviewers are out testing the Sony a7R III in Arizona, back in Seattle we slapped the camera in front of our studio scene to get a close look at its image quality. See how it stacks up against the competition.
We're counting down our top 10 most popular sample galleries of 2017, and the #8 ranking belongs to the Nikon D7500.
B+W has announced a new aluminum filter holder that offers three slots so users can use multiple filters at the same time. The holder goes with the 2mm thick 100mm square filters it launched earlier this year.
8K video is coming a lot faster than you think, and Blackmagic is ready for it. Meet the DeckLink 8K Pro, a new high performance PCI-E capture and playback card built to handle 'real time high resolution 8K workflows.'
"Glass is everywhere in photography. From Eugène Atget’s reflective vitrines to Lee Friedlander’s sly self-portraiture, photographers have long been in thrall to the visual complications glass can inject into a composition."
Former Apple Aperture lead developer Nik Bhatt has designed an iOS app called RAW Power that lets you edit raw photos from your professional camera using your phone and tablet.... color us intrigued.
Advertising photographer Blair Bunting got his hands on the new Microsoft Surface Book 2, and it blew him away. Bye bye MacBook Pro...
The OnePlus 5T retains many of the 5's features and specs, but comes with an edge-to-edge display and a dual-camera that is optimized for low light.
Sony's recently announced IMX461 backside illuminated medium format sensor will bring 100MP resolution and almost 2x the speed to the next-gen Fuji GFX and Hasselblad X1D.
With the ‘Rent a Hasselblad’ camera equipment renting program, the camera makers is aiming to give enthusiast and professional photographers easier access to its medium-format photography products.
They say seeing is believing, and that's exactly what happened when one DPR staffer took the Google Pixel 2 out for an afternoon shooting under challenging conditions.
We're counting down our top 10 most popular sample galleries of 2017. At the #9 spot we have the Fujifilm GFX 50S, a medium-format camera that took CP+ 2017 by storm.
Instagram is testing a new feature that lets you follow hashtags in addition to people, making it possible to keep track of your favorite #landscapes or #portraits without leaving your home feed.
Despite the gigantic volume of second hand film bodies in existence, it seems there is still a demand for new 35mm SLRs with a retro feel. The latest is a remake of the Ihagee Elbaflex from the 1960s, but with a Nikon F mount.
The Polaroid Insta-Share Moto Mod straps an instant printer directly to your Moto Z smartphone, so you can print your photos as soon as you've captured them.
The Mitakon Speedmaster 135mm F1.4 lens is being relaunched in 7 different mounts, including: Sony A, Sony E, Canon EF, Nikon F, Fujifilm G, Pentax K, and Leica L. Got an extra three grand lying around?
In January, Kodak announced it would bring back the beloved slide film Ektachrome. The timeline has been pushed back a bit, but Kodak says you can expect to purchase Ektachrome again in 2018.
Instagram popularity is threatening some of the most beautiful landscapes in the US, as hordes of 'nature lovers' trample over the same spots over and over again in search of the same exact shot.