Surreal HDR

<p>I have read numerous articles about HDR in magazines and on the net and in most of them they mention how some HDR images can look surreal or fantasy like. I'm not sure I've ever seen one of these "fantasy" HDR photos, or maybe I have and just didn't know that's how it was done. Could you please post some examples of surreal HDR photos so that I will know what these articles are talking about and so that I can recognize them in the future. Thanks.</p>

<p>Nathan, the trick with HDR is to make them look natural rather than processed! Take a look at this - very natural with a little HDR added in select areas. Yes, you don't have to do the entire photo if you are good with Photoshop. <a href="http://dustylens.com/Monument-Valley---South.jpg">http://dustylens.com/Monument-Valley---South.jpg</a></p>

<p>The last one is pretty much a full blown pseudo HDR.<br>

Keep in mind HDR really means 3-6 separate exposures that are then tone mapped. However, there are lots of software filters that make it easy to do pseudo HDR with a single exposure. All those I have posted fall into this single exposure pseudo HDR.</p>

<p >Subtle:</p>

<p >http://ghost-town-photography.com/Valdez,-Colorado.jpg</p>

<p >http://ghost-town-photography.com/Gleeson---1-PM.jpg</p>

<p >http://ghost-town-photography.com/Segundo,-Colorado-x.jpg</p>

<p > </p>

<p >And pushed a little more. This is on the edge of being too much.</p>

<p >http://ghost-town-photography.com/Dead-Bottles.jpg</p>

 

<p>Here's one of mine that I think falls in the surreal category.</p><div></div>

<p>Steve, those clouds are awesome!</p>

<p>stuck in customs<br>

Check out the whole site, there's no mistake you'll know them when you see them</p>

<p>Hi,<br>

As Steve says, one goal is to make photos that look realistic but using HDR. From what I understand, the human eye has a broader DR range than digital photos. Also the brain process the signals so that relative luminosity is more important than absolute luminosity. I have been trying to figure out how to do realistic HDR, so I am new at it. The following is my initial attempt.<br>

This is based on three separate photos that are at<br>

http://www.flickr.com/photos/9476880@N02/<br>

I am looking any advice on how to best do realistic HDR.</p>

<p>hi paul;<br>

hdr as most people practice isn't really a technique, it's just the "cheep" method of extending the "room" for the dyn-range of a scene; the dyn-range won't be impressed of your attempt to bracket and merge some exposures, it will always stay the same you just have the ability to extend the limitations of a 8 or 16 bit format;<br>

all common algorithms don't really generate a hdri you could use for production in cg, where this technique is applied since the 80s;</p>

<blockquote>

<p>the human eye has a broader DR range than digital photos</p>

</blockquote>

<p>this is not absolutely correct, depends on the lightning situation; even the human eye is limited but it has the ability of adaptation which makes it virtually more responsive to lightning conditions and the resulting dyn. range;</p>

<blockquote>

<p>so that relative luminosity</p>

</blockquote>

<p>in real live you have to differ from luminance and radiance; eve physicians have their own theories; in cg the hdri fro real-world captures is calculated from radiance; hdr-footage from the machine can contain real luminance information;<br>

btw. you "first" attempts look very good, hope you keep that style its quite natural and pleasant to view;<br>

cheers</p>

 

<blockquote>

 

</blockquote>

<p>HDR also brings out more deatil in some cases than was actually there in the first place, at least it looks that way.Its also a matter of perception, which as technology grows will change.We've had such limitations for so long in some cases we actually think thats the way things should be.<br>

Is HDR really high dynamic range or is it how things should have been all along? I sometime marvel at people being amazed by movies with 3D glasses when they have been around for quite sometime. When we lose the 3D glasses and see 3D without them that will be something, but its probably just another stepping stone to something even better. what some called HDR when it first was seen was oh its just another fad, now to some degree its being built into the cameras, instead of having software as the only wy to get it. I actually like the "painterly" look of some images, but the very fact we can have it either way is a testament to photography and all the processes we have available being as flexable as it is now.</p>

<p>@ bruce<br>

the funny thing is that stereoscopy is a technology almost 200 years old;<br>

by now we have the first devices to give us "real 3d" by technology;<br>

hdr is used since 1980 in all major studios; today everybody working in cg follows a 32 bit workflow;<br>

dyn. range will always stay the same; what you get from tonemapping of the extended "container" of data is detail in areas you would otherwise only capture if you understand the principles of photography and lightning, so bracketing your 3 shots handheld is much more comfortable, but in most cases the output is just awful;<br>

look at the example of kent; its just a bunch of colors, no depth in there its hard for the eye to separate all the super-satured elements and find a "focal"point;<br>

may be funny to play with but this kind of digital aberation is def. not related to photography anymore, the footage may have been some exposures but the output is a plain, inexpressive bunch of colors just about the effect and technology, subtract that from the composition you get an everyday snapshot;<br>

cheers</p>

<p>I plan on making natural looking photos, I just wasn't sure if I'd seen the surreal ones before. I have seen images like this, but I didn't realize it was HDR. Now I know. Thanks guys.</p>

<blockquote>

<p>very natural </p>

</blockquote>

<p>You folks have obviously worked very hard on these images, but I'm afraid that I'll have to disagree (respectfully) as to the "naturalness" of their appearance. The skies are impossibly dark (I have yet to see an indigo sky in "real life") and the foregrounds are almost fluorescent in their level of saturation.</p>

<p>Paul O's HDR images look "natural." They weren't necessarily taken in the most flattering light, but they look like what my eyes would have seen had I been standing there at that moment.</p>

 

<p>Nikolai,<br>

Thanks for the useful comments. I am still trying to get my head around the difference between luminance and radiance. Been reading some sites I googled, but still not completely clear because it seems like there are various definitions. Anyway, any additional explanation you can give me would be helpful.<br>

Dan,<br>

Thanks. Yes, very harsh lighting condition for the camera. HDR using three shots helped me achieve what looks realistic. Still trying to master the technique. It is easy to make unrealistic HDR by pushing various sliders. I think good surreal photos should be artistic not just not "natural". Getting good realistic HDR is also challenging.<br>

All,<br>

After reading a lot, I finally got a good way of phrasing what I have been trying to articulate and achieve. Realistic and useful HDR is based on compressing global contrast while maintaining local contrast in a way that it approximate what we perceive.</p>

<p> </p>

<blockquote>

<p>in cg the hdri for real-world captures is calculated from radiance</p>

</blockquote>

<p>sorry paul; was my fault hope it didn't confuse you even more;<br>

a picture of course only can have information of luminance; -> is something bright or dark;<br>

a cg-scene will have a light source that would emit light and have a given value of luminance/power by some definition;<br>

not to make it more complex a stupid example;<br>

imagine a complex scene with many light sources and objects/surfaces;<br>

talking of radiance, it would be the sum/"the brightness" of all these components in interaction at any angle;<br>

this model is so simple that it's almost wrong again but its kind of the way pictures are rendered , depending on the algorithm; from the virtual eye bouncing to the source or more complex, but correct and time-consuming^x from source bouncing to the eye;<br>

best regards</p>

 

<p>Bruce: <em>Is HDR really high dynamic range or is it how things should have been all along?</em><br>

Start from the output. Your monitor has a given contrast range which should be filled by the 0...255 of an 8-bit JPEG. <br>

Now, as input, you could have a very low contrast image - eg a bridge disappearing into the mist. Imagine the histogram: this fits into a narrow band at a stop above a midtone (zone VI), no data at 0 or 255. You're not using the full output range of the monitor - and you probably don't want to in the case of a misty photo anyway.<br>

Alternatively, imagine a vibrant landscape looking almost into the sun, from within a forest. The contrast range - bright sunlight to shadow-sides of tree-trunks - is going to be immense, say 11 or 12 stops or so. <br>

Now, your camera sensor is only going to have a dynamic range of about 7-8 stops (digital) or 4.5 stops (slide film). Always, imagine this as a section of the histogram. When you take the scene's histogram, you can place the slide-film's response to say "keep the highlights in" or "retain the shadows" and know that everything outside that 4.5-stop window is going to be lost. <br>

With HDR, all that happens is you build a wider histogram than you would otherwise have done. The luminosities represented by 0 and 2^32 are set miles further apart than your monitor can represent directly.<br>

If you were simply to re-scale that into the range 0...255, you would have a lot of contrast in a space designed for a smaller range: it will look low-contrast ie washed-out. That is pure HDR.<br>

To overcome it, we tonemap that image, ie boost the contrast - not in terms of the tone/response-curve, but spatially depending on *where* in the image we're looking. This is where your choice of any number of algorithms - mantiuk or reinhard or fattal or whatever - and associated parameters comes in. Oh, and a sense of taste: you can choose to aim for subtle effects that look moderately realistic, or you can choose to let rip and have every single tiny area of the shot contain vast normalized dynamic range, as you wish. </p>

<p>nikolai,<br>

Thanks. Cg is another world for me, but useful to think about.</p>