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roy5051
roy5051  12
28 May 2011 - 1:20 PM

Your HDR tutorial this month shows a truly awful picture in the heading. HDR, as I understand it, is a method of equalising the over- and under-exposed portion of a picture to get a more natural effect. Most HDR images I have seen, including this one, are truly awful and over-manipulated. Is this the future, or will this fad soon be consigned to the dustbin of photography?

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28 May 2011 - 1:20 PM

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User_Removed
28 May 2011 - 1:41 PM

You are missing a very fundamental point here, Roy.

Firstly, I agree with you that, to my taste, many HDR images you see are truly horrible. And it sometimes seems that the more grotesque they are, the more likely they are to be printed in magazines.

However, the essential point that you are missing is that the purpose of HDR is not "a method of equalising the over- and under-exposed portion of a picture to get a more natural effect" as you suggest (although that may be a by-product) but rather, to compensate for the serious deficiencies of the digital sensors we currently have in our cameras.

The dynamic range that can be captured by a digital camera sensor is considerably less than can be captured on film which, in turn, is very considerably less than that which can be detected by the human eye. The result is that a scene which, to the human eye, looks well graduated with a good tonal range may, in a digital camera image, have seriously burnt-out highlights and/or a serious lack of detail in the shadows.

HDR (I would much prefer the term "extended dynamic range" ) compensates for this by combining images taken with different exposures in such a way that the midtones from the "correctly" exposed image are blended with the highlights from the underexposed images and the shadows from the overexposed images, thereby producing a composite image that has fuller detail in both the highlights and shadows, closer to what the human eye can see.

The actual technique used will vary according to the scene being shot but, for most purposes, I find that 5 exposures at -2, -1, 0, +1 and +2 EV are adequate to achieve a marked improvement in the final photograph.

It is perfectly possible to do this subtly without "overcooking" the image in the manner that has become fashionable.

But, to answer your question "Is this the future, or will this fad soon be consigned to the dustbin of photography?", I don't think it is a fad. Done properly it is here to stay - at least until technology advances to give us a digital camera sensor with the same dynamic range as the human eye.

Last Modified By User_Removed at 28 May 2011 - 1:42 PM
User_Removed
28 May 2011 - 1:45 PM


Quote: I would much prefer the term "extended dynamic range"

Totally agree with that...

Last Modified By User_Removed at 28 May 2011 - 1:46 PM
roy5051
roy5051  12
28 May 2011 - 2:13 PM

I am certainly glad that my human eye cannot see the type of HDR shown in the image in the tutorial.

I think that what you wrote in your reply is just a long-winded description of equalising the tonal range. Combining 4 or 5 images is certainly capable of doing this without making the resulting image look unnatural. It is the unnaturalness of the resulting images that is so awful.

Jestertheclown
28 May 2011 - 2:17 PM


Quote: Totally agree with that...

Same here.
"Extended dynamic range" is a far better description of what's actually going on.

keithh
keithh  1022557 forum posts Wallis and Futuna29 Constructive Critique Points
28 May 2011 - 5:02 PM

It will be a long long time before digital sensors or film will ever equal the human eye. However it's the tone mapping that is at fault not the idea of multiple images taken to extend the dynamic range.

Carabosse
Carabosse e2 Member 1139367 forum postsCarabosse vcard England269 Constructive Critique Points
28 May 2011 - 5:04 PM

Maybe the pic was to show how not to do it? Wink

Carabosse
Carabosse e2 Member 1139367 forum postsCarabosse vcard England269 Constructive Critique Points
28 May 2011 - 5:24 PM

I'm assuming it is this pic that is the subject of discussion? The HDR + wide angle makes the effect rather jarring but maybe it looks a bit better if printed large? Certainly some people might find it "impressive" but perhaps the whole oversaturated landscape thing is a bit old hat now?

castle-on-the-coast.jpg

Nick_w
Nick_w e2 Member 63723 forum postsNick_w vcard England98 Constructive Critique Points
28 May 2011 - 6:16 PM

Done well a good HDR is almost impossible to tell from a straight shot. There was a thread a few months back where HDR images were posted against straight shots I would say 50 % were guessed wrong. As Keith says it's tone mapping, or more accurately poor use of that's the problem. Just because your car does 120mph you don't drive at at that speed everywhere, so why do so many wack up the sliders is photomatix to the maximum?

Have a look at few portfolios on here people like Keith, DaveU etc and you will see what's possible.

CathyT
CathyT e2 Member 87253 forum postsCathyT vcard United Kingdom18 Constructive Critique Points
28 May 2011 - 6:55 PM

Its HERE

Dave_Canon
28 May 2011 - 7:47 PM

I have no idea where some of the respondents get ther information from. The modern DSLR with a 14 bit sensor has a significantly larger dynamic range than any film I have used. Although there is plenty of scientific evidence to support this, my experience with film and digial certainly confirms this. Of course there is no reason why you cannot use HDR techniques with scanned film. You will be lucky to get more than about 9 stops from B&W film (less from colour film) but you should get 11 stops from a good 14 bit DSLR sensor. There is no doubt that used carefully HDR techniques can result in a photogrpah which is similar to that perceived by the eye/brain (allowing for pupil dilation). On the other hand it can be applied more agressively to provide more infoprmation than would have been percieved by eye/brain alone (it is a matter of opinion whether this is good). Over the top HDR can be used for artistic expression but, as always, at the risk that many might disapprove. I doubt that HDR will go away but more likely that the dynamic range of cameras will increase further so it will be built in.

Dave

User_Removed
28 May 2011 - 8:40 PM


Quote: I have no idea where some of the respondents get ther information from.

From much more reliable sources than you, Dave.

For example:

"The dynamic range of sensors used in digital photography is many times less than that of the human eye and generally not as wide as that of chemical photographic media. In the domain of digital imaging, algorithms have been developed to map the image differently in shadow and in highlight in order to better distribute the lighting range across the image. These techniques are known as local tone mapping, and usually involves overcoming the limited dynamic range of the sensor array by selectively combining multiple exposures of the same scene in order to retain detail in light and dark areas. The same approach has been used in chemical photography to capture an extremely-wide dynamic range: A three-layer film with each underlying layer at 1/100 the sensitivity of the next higher one has, for example, been used to record nuclear-weapons tests.[22]

The most severe dynamic-range limitation in photography may not involve encoding, but rather reproduction to, say, a paper print or computer screen. In that case, not only local tone mapping, but also dynamic range adjustment can be effective in revealing detail throughout light and dark areas: The principle is the same as that of dodging and burning (using different lengths of exposures in different areas when making a photographic print) in the chemical darkroom. The principle is also similar to gain riding or automatic level control in audio work, which serves to keep a signal audible in a noisy listening environment and to avoid peak levels which overload the reproducing equipment, or which are unnaturally or uncomfortably loud."

or

"The dynamic range represents the amount of contrast a given capture device can record. Film and digital sensors are able to record a fixed range of contrast. This range varies from film to film and sensor-to-sensor, or rather analog to digital converter (A/D converter) since in a digital camera it is the converter that controls dynamic range. Even a 16-bit A/D converter can only capture a dynamic range of 16 stops at the very maximum. However, most Digital Single Lens Reflex cameras as of Fall 2006 use a 10 to 14-bit A/D converter, which translates into a dynamic range of 10 to 14 stops. Even then this dynamic range is limited by noise levels, meaning that shadow areas in the image where detail was captured may exhibit so much digital noise as to be visually unattractive and best rendered as pure black.

Sensors are far better than film when it comes to dynamic range, being able to capture a much wider dynamic range than film, on average. However, this pales in comparison to the human eye which is not only able to see details in a scene containing a contrast range of nearly 24 stops, but also able to instantly change its contrast-perception ability in order to see, alternatively, details in highlights and in shadow areas without the conscious awareness that we are doing so. In other words, the human eye-brain apparatus is not limited to a fixed dynamic range, but instead can adapt to whatever the light situation calls for. If you doubt this statement, or find yourself calculating the exact difference in dynamic range between sensor “x” and the human eye, pause for a second and ask yourself if you ever heard someone say, “I cannot see this landscape because it exceeds the maximum dynamic range that my eyes can capture.” Indeed, you haven’t. You haven’t because humans do not see the world like cameras see it when it comes to contrast.

The fact is that our eyes are far superior to the best films or digital sensors currently available. It is this superiority that, in part, causes us to be disappointed when we see the results of our efforts at capturing what we see with a camera.

Resolving this contrast issue means creating an image whose contrast is closer, or similar, to what we saw. This means either reducing or increasing the contrast of the photograph to make it match what we saw. In some instances, such as with photographs where large areas of shade and sunlight are present in the same image, it means both increasing and decreasing the contrast of the scene, again to match the way our eyes adjust to seeing shadowed and directly-lit areas. Our eyes see these two areas differently – reducing and increasing contrast alternatively - and the photograph of such a scene needs to be altered in a manner that reproduces this approach."

So we have two authorities who differ on the relative dynamic ranges of digital sensor and film, but who agree that both are far more restrictive than the human eye.

Then, of course, you get into the problem of the display medium - what dynamic range can a computer monitor or a sheet of paper display?

More complex than you suggest, Dave, but the reason for HDR processing remains to produce a more natural image (defined as that seen by the human eye) than the sensor (or film) will produce without such processing. Now, where we would agree, is that when it comes to artistic interpretation, a "natural image" is not always the desired end product.

Last Modified By User_Removed at 28 May 2011 - 8:50 PM
collywobles
29 May 2011 - 8:16 AM

Regardless of the reasons and technicalities of HDR - I love them!.

joolsb
joolsb e2 Member 927107 forum postsjoolsb vcard Switzerland38 Constructive Critique Points
29 May 2011 - 8:21 AM


Quote: Sensors are far better than film when it comes to dynamic range, being able to capture a much wider dynamic range than film, on average.

Sweeping generalisations. Doncha just love 'em?

Obviously that rather depends on the film you're talking about. A slide film like Velvia gives you a meagre 4.5 stops whereas a colour neg film, like Kodak Portra, will give around 12 stops or more. Some monochrome films will give you as much as 15 stops.

I don't think digital is quite there yet....

Last Modified By joolsb at 29 May 2011 - 8:22 AM
ge22y
ge22y  5115 forum posts Wales12 Constructive Critique Points
29 May 2011 - 9:39 AM


Quote: I doubt that HDR will go away but more likely that the dynamic range of cameras will increase further so it will be built in.

Nikon are already on the way, there's a function On my D300s and was on my Fuji S5 called multiple exposure, it allows you to take between 2 and 10 frames, then combines them into 1 image in camera, its a fun little feature.

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