Please explain High Dynamic Range

[Jannie]

A friend who spends tons of time in PP, recently bought a book on High Dynamic Range but as of yet has been only able to tell me it's fantastic but unable to explain what it does.

My question is this something that can be applied to improve photos (subjectively how) and is it something that can be done in PP with a single exposure or does it have to be done with tripod mounted multiple exposures?

[canonphotog]

There is software that can create an HDR image from one image. There are also methods where you can create a group of different exposed images(from one image) and then merge them to HDR.

Some scenes simply don't hold still for bracketed images on a tripod, hence the above.

HDR is very subjective. I would recommend you borrow your friends book when possible if you are interested in experimenting with HDR

[johncolby]

Hi Jannie! There are 2 parts to doing HDR photography, and they both work towards expressing more of the tonal details of the actual scene in the image you present. This ideally lets your image convey a scene closer to what your eyes "experienced":

1. Capture more of the dynamic range. This usually involves taking bracketed exposures, so that between them all, every part of the scene is well-exposed in at least one shot.

2. Mapping this "high dynamic range" information into a regular 8bit jpeg image for presentation. This involves using the tone mapping algorithm in Photoshop or Photomatix or similar.

Here's a really good intro tutorial to get you started:

Stuck in Customs HDR Tutorial 2008 (http://stuckincustoms.com/2008/01/30/updated-hdr-tutorial-for-2008/)

[Jannie]

I checked out the tutorial but most of the example photos don't come through and those that do look heavily saturated and heavily processed, very much like the prints from the earlier days of Photoshop when there was a tendency to colorize to extremes.

I do still intend to learn what I can and see what there is from it I can use.

[johncolby]

Haha yea Trey's work is definitely towards the extreme end of the HDR processing spectrum, but it's a great example of what can be done. You can always dial back the effect within the tone mapping dialog or with a layer opacity change. Good luck!

[tzalman]

Jannie, contrary to what was written above, a true HDR can only be made from multiple exposures because that is the only way to capture a tonal range greater than the DR of the camera. However, because HDR has become a fad recently many people have sought to circumvent that requirement by blending multiple conversions from a single RAW, which cannot, of course, create more data than the RAW contains and should be called faux-HDR, although it is a perfectly legitimate way to get the most out of the RAW. Moreover, as you saw, many of these images are over-saturated, over-sharpened and contrasty to the point where their color palette is greatly compressed and posterized. In fact, a lot of people - who seem to not even know what the letters HDR stand for - consider this comic book appearance as highly to be prized.

[Jannie]

"consider this comic book appearance as highly to be prized."

Admittedly this was one of the early reasons I was so turned off to digital photography, my film friends and I used to refer to it as "The Photoshop Look" and were convinced photography was ruined forever.

I've learned however that photography as I love it not only lives but excells in many areas today with new technology and the use of it. However if something can be learned in part of HDR or faux-HDR in a way that excites my own pallet then I'll use what I can.

I was in Art Wolff's gallery last summer and was looking through the many photos and books; there was a period of time where his photographs had some of this oversaturation look and it had seemed to be a fad that passed on. But like the zoom lens in cinematography, when new it was so over used as to make one nauseous but later on it simply earned it's right as a very good tool.

[johncolby]

Here's a link to James Neeley's Flickr. He's another very popular HDR guy that uses somewhat less heavy processing compared to Trey. Still quite a bit though. Anyway, it's a good stream to check out:

James Neeley's Photostream (http://www.flickr.com/photos/jpn/)

[tzalman]

However if something can be learned in part of HDR or faux-HDR in a way that excites my own pallet then I'll use what I can.

Agreed, and what I think can be gained from the single RAW method is that judicous placement of the white point during conversion plus expoitation of modern converters' ability to reconstruct apparently lost highlight data at the high end of the range, blended with a conversion that maintains the advantages of doing shadow lifting in linear RAW space can maximize the utilization of the available DR. Sort of MDR instead of HDR.

[Serrator]

... However, because HDR has become a fad recently...

HDR a fad? Please elaborate on your determination of this.

My understanding of a fad something that comes and goes relatively quickly, HDR has been around for many years and continues to grow.

Not only that but camera makers are marching forward toward the higher amounts of dynamic range capability that we currently must use work-arounds to achieve.

So a fad...not to me, but a progression to the most visually accurate reproduction of high contrast scenes currently available to the masses.

[kirkt]

See this very informative website:

http://www.hdrlabs.com/news/index.php

High dynamic range imaging is a technique used to capture the full dynamic range (ie, the ratio between the darkest and lightest tones) in a scene into a single image. Your dSLR sensor can capture about 7 to 8 stops (exposure values) of light in a single shot, which may be suitable for a lot of scenes you shoot. However, some scenes contain a much higher dynamic range - for example an interior shot with a window looking onto an outdoor scene lit by sunlight. The darkest shadows inside contain the lowest light data and the brightest highlights outside contain (typically) the brightest light data - these elements may span a dynamic range of 10 or 12 stops, for example (sometimes higher). If you try to pick the "proper" exposure for a single shot of this scene, you will end up either blowing out the brighter data or plugging up the darker data, or both. The goal of HDR imaging is to take a sequence of exposures of the same exact image and combine them mathematically into a single, High Dynamic Range image dataset. There are a few guidelines for capturing the image sequence, a bunch of tips can be found here:

http://www.hdrlabs.com/tutorials/index.html

Once you have your HDR image data, you need to compress the dynamic range into something viewable on current 8 bit devices like monitors or printers. This operation is called "tonemapping". This is where people will play with software like Photomatix and get the often cartoonish looking images that were referred to above. From a single HDR dataset can come countless tonemapped images - it becomes a matter of personal taste and interpretation of the data (think of it like developing a negative and making a print). Some people go for subtle tonemapping to bring out simultaneously the highlight and shadow detail that a single exposure would not be able to capture but that their eyes could see at the moment of capture (the human eye can see about 14 stops of data simultaneously and can adapt to an incredibly vast dynamic range). Some people go for a more impressionistic or artistic interpretation that deviates from photorealism.

It should be noted that a single RAW file will not constitute a true high dynamic range image dataset, as most sensors record about 7 to 8 stops of light and 10-12 bits of data (unlike a true HDR which is 32 bits). The above "bit" values are per channel. That being said, ou can use HDR tonemapping software to tonemap any file, including a traditional 8 bit file. When you use curves and levels in Photoshop, you are tonemapping; however, HDR tonemapping apps usually have more sophisticated operators that do things like accentuate local contrast, or manipulate the data to mimic the human photoreceptor, etc. So, you can get funkier effects with these more sophisticated tonemaping operators without having to know a lot of the under-the-hood mechanics of using curves, channels, etc.

The bottom line is, sometimes a scene has a dynamic range that is greater that the camera's ability to capture it in a single exposure. This is when HDR imaging shines as a technique for capturing the full highlight and shadow detail. Sometimes people like the "HDR effect" and will shoot a multiple image exposure sequence on a scene that does not require it, only to be disappointed by the results. Remember - your scene needs to have a high dynamic range if you really want to take advantage of the HDR technique. However, if all you are after is the "look", you can tonemap any image to give you the contrast and saturation enhancement.

As a sidenote - in the world of computer generated imagery, HDR is great because you can use it to capture the lighting data for a real life scene by shooting an HDR image dataset of that real life scene. You can then wrap that data around your computer generated modeling environment and use the real life lighting data to light the computer models (a technique called Image Based Lighting) - this makes for photorealistic and convincing compositing of CG models into real life footage or background plates. This technique has, in part, been responsible for creating the recent interest in HDR photography.

Have fun!

Kirk

[Jannie]

This is getting interesting.

[kirkt]

Yes it is interesting! Here is an example of an image sequence of the standard interior-with-window shot:

http://kirkt.smugmug.com/gallery/1156911_9Le6z#53986257_KNrGv

Nothing fancy, but you can see the concept. This particular image sequence was captured automagically to the computer via tethered camera connection with Greg Ward's CanonHDRCap script. Greg Ward is the father of the .HDR file format and a pioneer in the creation of modern HDR imaging. The tonemapping I performed on the final HDR data is very neutral and not really geared to an aesthetically pleasing final image, but you can appreciate the difference in the shadow and highlight detail of the tonemapped HDR versus any of the individual exposures that went into construction of the HDR.

If you have not, go visit the HDR forum section here and see what's what!

Kirk

[Jannie]

It's clear the value in certain circumstances to avoid having to light an interior to bring it up when you have to show a large expanse of windows like that. I can also see where this could be really good for some landscape and architecture work, it could be a real help.

[Lowner]

Serrator,

"HDR a fad? Please elaborate on your determination of this".

99% of all the HDR pictures I have ever seen have looked as though a small child has been let loose in a crayon factory. There is absolutely no subtly to it. All the UK photo magazines are full of examples, they win prizes and are highly praised. But all the time I'm thinking "God, thats bloody awful"!

Rather like the "current" move away from time exposures of water that turn streams and seas into milk, there will come a time when users shy away from HDR because its been seen many times too often.

[Technician X]

Serrator,

"HDR a fad? Please elaborate on your determination of this".

99% of all the HDR pictures I have ever seen have looked as though a small child has been let loose in a crayon factory. There is absolutely no subtly to it. All the UK photo magazines are full of examples, they win prizes and are highly praised. But all the time I'm thinking "God, thats bloody awful"!

Rather like the "current" move away from time exposures of water that turn streams and seas into milk, there will come a time when users shy away from HDR because its been seen many times too often.


One man's garbage is another man's treasure. You don't like high saturated HDR that's fine. I'm sure I'm sure there's 20+ pro guys that think your work is "bloody awful" I mean this as an example. I've not actually seen your work.

Live and let live. If it was all the same it wouldn't be art.

Tech. X

[Serrator]

Serrator,

"HDR a fad? Please elaborate on your determination of this".

99% of all the HDR pictures I have ever seen have looked as though a small child has been let loose in a crayon factory. There is absolutely no subtly to it. All the UK photo magazines are full of examples, they win prizes and are highly praised. But all the time I'm thinking "God, thats bloody awful"!

Rather like the "current" move away from time exposures of water that turn streams and seas into milk, there will come a time when users shy away from HDR because its been seen many times too often.

Lowner,

I won't argue that there are many HDR enthusiasts who like to push and shove their images to the surreal extremes...more power to them. Although getting these type images are not only confined to HDR but any number of methods. Understand though for me I will not use what I consider to be the poor examples as my basis for throwing out a technique...I look at the great results I can find or create and use that to determine its value. So for you are the 1% of acceptable images worthy of consideration of this tool?

Anyway, this has nothing to do with the original question as to why some think of HDR as a "fad". Now if you are confining your opinions to only the so called 'velvet elvis' looking HDR creations than perhaps this might be a valid point. I see HDR as it has been adopted to help overcome high contrast scenes for photography. This is not a fad, it is a tool and technique and sometime in the future to be replaced by new cameras that can handle the higher dynamic ranges we all encounter.

Since I don't know what you consider to be worthy HDR examples I will link you to a few of mine and you can tell me if these are the "crayon factory" disasters that you despise or something else (btw these are all 3 exp -2,0+2):

http://www.flickr.com/photos/serrator/1317038100/sizes/l/in/set-72157601660525826/

http://www.flickr.com/photos/serrator/1281511181/sizes/l/in/set-72157601660525826/

http://www.flickr.com/photos/serrator/1352322625/sizes/l/in/set-72157601660525826/

http://www.flickr.com/photos/serrator/2503396691/sizes/l/in/set-72157605132667057/

http://www.flickr.com/photos/serrator/2061495048/sizes/l/in/set-72157594403866898/

http://www.flickr.com/photos/serrator/2709357044/sizes/l/in/set-72157606340150948/

Lastly have you even tried to create an HDR from a high contrast scene? Don't let others creations determine your final results, your mileage may be better!

[johncolby]

Great work, serrator! I especially enjoyed the first one and the last one.

[Serrator]

Thanks John.

I read that you are working with MRI's for the brain. I have a good friend who is a brain surgeon and he has invited me in on a couple of surgeries. He uses the Brainlab VectorVision system in conjunction with the MRI's...very cool stuff.

[Guapo]

Very nice, Serrator. That is an example of what I do like about HDR. It allows you to get closer to what your eye sees.

Personally, I typically don't like the crayon look images, but some of them are pretty interesting from a visual standpoint, even if they no longer look like photographs.

[johncolby]

Hey Serrator...neat opportunity! That's some really high tech equipment...puts even the price tag of the d3x to shame. ;) Speaking of medical equipment though, the newer digital imaging systems (x-ray, etc.) remind me of HDR photography because they record a much higher dynamic range than a monitor can display. The viewer has to scroll through the whole range of "window" settings (like scrolling through our bracketed set of exposures) to see all the info. Makes me wonder what these images would look like if you ran them through Photomatix?!

[Serrator]

Very nice, Serrator. That is an example of what I do like about HDR. It allows you to get closer to what your eye sees.

Personally, I typically don't like the crayon look images, but some of them are pretty interesting from a visual standpoint, even if they no longer look like photographs.


Thanks Guapo. I do strive to achieve as naturalistic imagery as I can with the tools I have. I do appreciate the input.

[Serrator]

Hey Serrator...neat opportunity! That's some really high tech equipment...puts even the price tag of the d3x to shame. ;) Speaking of medical equipment though, the newer digital imaging systems (x-ray, etc.) remind me of HDR photography because they record a much higher dynamic range than a monitor can display. The viewer has to scroll through the whole range of "window" settings (like scrolling through our bracketed set of exposures) to see all the info. Makes me wonder what these images would look like if you ran them through Photomatix?!

It is interesting how they incorporate the MRI scans to the VectorVision so that the surgeon has sub-millimeter accuracy with his stylus (not sure of the correct term for the pointer). Although when they clamped on the registration assembly (three spheres contraption) to the head was a bit brutal.

I did not know that the newer gadgets had that much DR. It would be interesting to see what would happen if we tonemapped it! I may ask my friend if I can get my hands on some of these type images to play with!

[Lowner]

TechX,

"Live and let live. If it was all the same it wouldn't be art".

I totally agree, but the question had been asked and thats my answer. It's a free world.

[René Damkot]

Moved this to the HDR section of the forums ;)

[canonloader]

99% of all the HDR pictures I have ever seen have looked as though a small child has been let loose in a crayon factory. There is absolutely no subtly to it.
Richard, what's your point? :lol:

Explain love, or art or red. The point is, it's a personal thing for each person and a total waste of time trying to tell someone else what it is, when he sees or knows what it is.

[toyoufromzero]

great thread!