1 EV is equivalent to 1 F-Stop of brightness


These Contrast Ration (CR) figures are approximate

Dynamic Range

Today, many people think HDR refers to the practice of merging bracketed exposures with software, but HDR actually applies to everything in an imaging workflow – capture, processing, display, and printing.

What is HDR? HDR is an acronym that stands for High Dynamic Range. It’s the opposite of LDR or Low Dynamic Range Imaging.

What is dynamic range? In imaging, dynamic range (DR) is the highest overall level of contrast found in an image. In other fields, such as in the audio industry, dynamic range is used to describe similar phenomena. In audio, DR is defined as the logarithmic ratio between the largest readable signal and background noise. DR is akin to signal-to-noise ratio. In imaging, DR refers to the entire image. Consider an image a signal – and every signal has some noise.

The values used to specify dynamic range can be charted on multiple scales. Whatever language is used to describe this phenomenon, two critical factors must be addressed; the total range of brightness and the fineness of the steps used within the scale.

Two scales are most useful for images – exposure value and contrast ratio. Exposure value (EV) is easier to use while contrast ratios better display logarithmic increases in light intensities. Both refer to the same phenomenon – relative increase or decrease in brightness.

The EV scale makes it easy to compare the ratios rather than the big numbers of logarithmic progressions; each successive EV rating represents a doubling of values. The exposure value (EV) scale has been used by photographers for ages. The International Organization for Standards (ISO) defines EV 0 at an aperture size of 1 and a 1 second exposure time. The same EV can be achieved with any other combination of fstop and shutter speed that produces the same amount of light.

‘The contrast ratio scale specifically delineates values; when you use this rating you instantly see how much greater each step in a progression is than the previous one because the numbers are so much bigger. You can convert EV to contrast ration or vice versa with the right formulas. 2 (power of EV) = contrast ratio (2*8=256 for a contrast ratio of 256:1) or EV=log10(contrast ratio)*3.32 (log10(4000)*3.32=12EV

Dynamic range, gamut, and bit-depth are often confused. Though related, they’re all different. Dynamic range refers to a total range of luminosity values. Gamut refers to a total color capacity, including saturation. Bit depth refers to the number of points of data between values or the fineness of the increments in the scale. Just because an image is wide gamut doesn’t mean it is HDR or has high bit depth, but it will contain more and potentially better data if it does. Just because an image is HDR doesn’t mean it is wide gamut and has high bit depth, but it will contain more and potentially better data if it does. You can’t convert low dynamic range, small gamut, low bit depth information to high bit depth, wide gamut, high dynamic range information. To get it and use it, you have to capture high quality information upon exposure and preserve it throughout your workflow.

How the Eye Sees

In many ways, the human eye is inherently HDR. The human eye can see a contrast ratio of up to 1:10,000 or 14 EV at any one time. And, it can adapt to varying amounts of light, extending that contrast ratio to almost 1: 100,000,000. The eye has a physical response (pupils dilate) and an incredible sensitivity (as few as 30 photons). The eye (like all of our senses) has a nonlinear response; the power of a signal needs to increase logarithmically to produce a response twice as strong. So, highlights are naturally “compressed”. The eye has local adaptation; it applies different sensitivities to different regions in our visual field of view. This last ability is extraordinarily complex. The eye is not a completely separate organ but rather an integral part of our brain. Perception is always accompanied by interpretation. Perceiving value is a coordinated construction process that considers shape, color, light, and filtration. This happens subconsciously and cannot be prevented – but you can become more aware of it. At this point physics, biology, psychology, and philosophy all intersect.

How the Camera Sees

The camera eye is not HDR, yet. While tomorrow’s cameras may become inherently HDR, today’s camera’s can be used to produce HDR images with software. Like the human eye, film has a nonlinear response to light. For film we adjust the EV to fit the amount and contrast ratio of the available light into the most useful area of its curve response. Using film, you expose generally and when compromises need to be made you favor shadows or highlights. Details lost at the point of capture are irrecoverable.

Unlike the human eye, CCDs have a linear response to light. It simply counts photons, with no scaling. Consequently, in linear capture (Raw) half the data in the file is contained in the top EV of the tonal scale and the quality of the data in the lowest EVs is comparatively poor (susceptible to noise and banding). Raw files without conversion look very dark. When converted a tone curve is applied (gamma encoded) to make them appear normal. The images are mapped to an output referring standard.

Today, camera capture, film and CCD, offer roughly 8 EV compared to the eye’s 14 EV. Tomorrow, in this fast evolving field, the EV of photographic capture will be much higher, higher than today’s software solutions offer, and quite possibly even higher than the capabilities of the human eye.

HDR Software – Merges

Comparatively recent advances in software technology allow us to combine the data from multiple bracketed exposures into a single file. Here’s the fundamental difference between a single Raw file and an HDR file created from multiple Raw files. A Raw file captures the scene as a sensor sees it. An HDR file captures the full values of the scene. You can “reexpose” this HDR scene digitally as often as you like by taking a snapshot of it and developing an LDR image for output.

Rather than applying output referring gamma curves to an image, you choose how the tonal values are rendered. Tone mapping takes a scene referred to an output referred state. Once merged into an HDR image, exposure becomes adjustable; you can select any single exposure or any combination of all of the exposures; you can even do this selectively.

The extra data gives you astonishing fidelity and flexibility. You lock into a solution only when you render the image to LDR. If you preserve the HDR image, you can always return to it and rerender it, in another way, at another time. HDR is essentially not bound to the limits of a capture device or an output referring rendering.

32 Bit

HDR merges use 32 bit editing spaces to hold all the data contained in multiple 16 bit bracketed exposures. Creating an HDR file from 16 bit (65,536 shades of gray) capture does not create a true 32 bit (4,294,967,296 shades of gray) file. Few capture devices today deliver a full 16 bits of data. Software, like Photoshop, use 16 bit editing spaces to hold data over 8 bit (256 values). (As an aside, for complex coding reasons, a 16 bit file in Photoshop actually offers 15 bits of data plus 1 value or 32,768+1.) 32 bit file sizes are twice as large as 16 bit files (4 times as large as 8 bit files).

Adjustments made to high bit data display fewer artifacts, but, whether significant or insignificant, there are artifacts nonetheless. Tweak more and you continue to lose values and encounter rounding errors, possibly producing noise and banding. Raw files adjust the appearance of a file during conversion to a gamma encoded color space. Whether 8 or 16 bit, these are still LDR solutions; only whole values exist (128 or 129). HDR floating point solutions allows for decimals (128.1 or 128.15)(You can split the bit.) providing a near infinite number of values. No gamma is needed because you can get finer levels whenever you need them. Image data can then stay in linear space, unchanged by our perception of them. The upper and lower limits disappear. You can assign any value to any pixel and then adjust the relative relationships of other values to it. Depending on how a tonal structure is mapped, values may stray out of the histogram – what’s being used – but they are never lost.

As there are currently no 32 bit devices, 32 bit files must be rendered (interpreted) to be seen.

Displaying HDR

Currently, viewing HDR images is challenging. We use LDR monitors, LCD monitors achieve 9 EV, which can give us only a limited preview of the total data contained in an HDR file. However, technology is constantly advancing. Canon/Toshiba SED monitor technology offers 17 EV (or 1:100,000) and Brightside LCD/LED combination monitor technology offer an EV of 18 (or a contrast ration of roughly 1:200,000). What will tomorrow’s monitors look like?

Printing HDR

Images in print are limited to roughly 6 EV. You can move the smaller window of the printable DR up or down within the larger captured DR; the larger that captured DR the more flexibility you have. HDR offers more options in print. It doesn’t offer higher dynamic range print materials. It’s difficult to create a surface that reflects less than 1% of the light it receives and impossible to create a surface that reflects 100% – though light emitting substrates exist today and will become increasingly available tomorrow. Many new technologies are starting to expand the 6 EV in print limit. There’s still a great deal of room for improvement before we catch up to the eye’s 12 EV.

HDR Is About Creative Control

How far do you want to go with HDR? It’s really up to you. But, you probably don’t want to go as far as you might think. As the brain tries to decode reflected light based on what it sees, extreme ranges of illumination may hinder rather than help perception. The artist who removes excess dynamic range in an image may actually make it easier for you to see the scene, than if you had to view and interpret it. To a large extent, finished images are already fully interpreted. HDR imaging techniques do more than solve technical challenges, they also give you the greatest freedom of interpretation. HDR technology and practices give you maximum control over the look and feel of your images.

HDR imaging (sensors, processing, and viewing) is the future of photography; it has been since the invention of photography and it continues to be today.

Read more on HDR techniques here.

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Marc Silber brings us another inside look at Ansel Adams’ world.

“Step inside Ansel Adams’ house and studio in this episode of Advancing Your Photography. Ansel’s son shares stories about his father’s lesser known commercial work and his teachings. Plus we get an up close look at Ansel’s personal camera collection! ”

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Enjoy this collection of quotes by photographer Duane Michals.

“Trust that little voice in your head that says ‘Wouldn’t it be interesting if…’; And then do it.” – Duane Michals

“Don’t try to be an artist. Find the thing within you that needs to be expressed. You might find it is art.” – Duane Michals

“I am an expressionist and by that I mean that I’m not a photographer or a writer or a painter or a tap dancer, but rather someone who expresses himself according to his needs.” – Duane Michals

“People believe in the reality of photographs, but not in the reality of paintings. That gives photographers an enormous advantage. Unfortunately, photographers also believe in the reality of photographs.” – Duane Michals

“Photography deals exquisitely with appearances, but nothing is what it appears to be.” – Duane Michals

“I never photograph sunsets and I never photograph moonrises. I’m not interested in what things look like.” – Duane Michals

“You can never capture a person in picture, never. You might get an interesting expression or gesture. I almost never research a picture subject ahead of time. I think Karsh is full of baloney. Can you imagine spending a whole week out in La Jolla with Jonas Salk soaking up his ambiance, then wind up making him look as if he’s in the studio in Ottawa with his thumb under his chin?” – Duane Michals

“Because of my involvement with my photographs, it is difficult for me really to see them objectively. Talking about them is like talking about myself. The only real idea that I have about them is that they are essentially snapshots. For snapshots, I feel, often have an inherent simplicity and directness that I find beautiful. The roots of my photographs are in this tradition.” – Duane Michals

“However, I think that the photographer must completely control his picture and bring to it all his personality, and in this area most photographs never transcend being just snapshots. When a great photographer does infuse the snapshot with his personality and vision, it can be transformed into something truly moving and beautiful.” – Duane Michals

“The best part of us is not what we see, it’s what we feel. We are what we feel. We are not what we look at . . .. We’re not our eyeballs, we’re our mind. People believe their eyeballs and they’re totally wrong . . .. That’s why I consider most photographs extremely boring–just like Muzak, inoffensive, charming, another waterfall, another sunset. This time, colors have been added to protect the innocent. It’s just boring. But that whole arena of one’s experience–grief, loneliness–how do you photograph lust? I mean, how do you deal with these things? This is what you are, not what you see. It’s all sitting up here. I could do all my work sitting in my room. I don’t have to go anywhere.” – Duane Michals

“I write in order to express what the photo itself cannot say. A photograph of my father doesn’t tell me what I thought of him, which for me is much more important than what the man looked like.” – Duane Michals

“Photography does deal with ‘truth’ or a kind of superficial reality better than any of the other arts, but it never questions the nature of reality – it simply reproduces reality. And what good is that when the things of real value in life are invisible?” – Duane Michals

“I believe in the invisible. I do not believe in the definitive reality of things around us. For me, reality is the intuition and the imagination and the quiet voice inside my head that says: isn’t that extraordinary? The things in our lives are the shadows of reality, just as we ourselves are shadows.” – Duane Michals

“Photographers tend not to photograph what they can’t see, which is the very reason one should try to attempt it. Otherwise we’re going to go on forever just photographing more faces and more rooms and more places. Photography has to transcend description. It has to go beyond description to bring insight into the subject, or reveal the subject, not as it looks, but how does it feel?” – Duane Michals

“I believe in the imagination. What I cannot see is infinitely more important than what I can see.” – Duane Michals

“Photography is essentially an act of recognition by street photographers, not an act of invention. Photographers might respond to an old man’s face, or an Arbus freak, or the way light hits a building—and then they move on. Whereas in all the other art forms, take William Blake, everything that came to that paper never existed before. It’s the idea of alchemy, of making something from nothing.” – Duane Michals

“I use photography to help me explain my experiences to myself.” – Duane Michals

“I think photographs should be provocative and not tell you what you already know. It takes no great powers or magic to reproduce somebody’s face in a photograph. The magic is in seeing people in new ways.” – Duane Michals
Duane Michals

“I am a reflection photographing other reflections within a reflection. To photograph reality is to photograph nothing.” – Duane Michals

“All good work has magic in it, and addresses the mind in a subtle way.” – Duane Michals

“Art is really whispering, not shouting.” – Duane Michals

“My gift to you is that I am different.” – Duane Michals

View 12 Great Photographs By Duane Michals.

Watch Duane Michals talk about his art.









Duane Michals heisenberg's magic mirror of uncertainty 1998 shot for French Vogue




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22 Quotes On Flow

September 7, 2016 | Leave a Comment |


Enjoy this collection of quotes on the state of flow.

“Let’s make things exist and then judge later. Don’t cancel the process of creativity too early: Let it flow.” – Ross Lovegrove

“One of my teachers once said that the way you know you’re on the right path is that it works. Now, that doesn’t mean you don’t run into blocks and brick walls, but it does mean that you can find a way around them or find a way to change yourself or your project in order to find the flow again and have it work.” – James Redfield

“I live my life on self-believe and I live it partly on going with the flow.” – Melanie Brown

“Life is so much easier when I allow myself to be myself and go with the flow. Whatever that looks like on a given day. If I can get quiet enough to truly check in with myself, I usually end up on the right track.” – Taylor Schilling

“The most important part of life is work, it’s the flow, it’s getting stuff done, feeling like you’re doing something.” – Penn Jillette

“My hand does the work and I don’t have to think. In fact, were I to think, it would stop the flow. It’s like a dam in the brain that bursts.” – Edna O’Brien

“Thoughts create a new heaven, a new firmament, a new source of energy, from which new arts flow.” – Paracelsus

“The idea flow from the human spirit is absolutely unlimited. All you have to do is tap into that well.” – Jack Welch

“The self expands through acts of self-forgetfulness.” – Mihály Csíkszentmihályi

Read more

“Challenges and problems can derail your creative process … or they can make you more creative than ever. In the surprising story behind the best-selling solo piano album of all time, Tim Harford may just convince you of the advantages of having to work with a little mess.”

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