Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: marvpelkey on November 13, 2012, 11:53:19 pm

Title: HDR
Post by: marvpelkey on November 13, 2012, 11:53:19 pm
Trying to get a handle on HDR as I have little to no experience on this topic.

Given that an images max DR is restricted by pure black at one end and white at the opposite, am I correct that putting a "scene" (by way of multiple image exposed differently) through the HDR process only results in finer levels of tone? In other words, it doesn't make the ruler any longer, it just divides the ruler into finer increments? Presumably, this is impacted by the DR of the medium (i.e. monitor, print etc) as well.

Or, if a camera sensor is capable of say, twelve stops, can HDR actually result in an image that is, say, thirteen stops (so the ruler actually lengthens)? And if this is the case, what is the limit?

Have tried reading up on this subject, but so far it's a bit unclear.

Marv
Title: Re: HDR
Post by: ErikKaffehr on November 14, 2012, 12:32:17 am
Hi,

You make the ruler longer. There is no limit, but there are a lot of issues. Good HDRs are not easy to make.

HDR is really a two step process:

1) You combine several images into a HDR image

2) You "tone map" the image so it can be presented on a device with a normal dynamic range.

The tone mapping process decides if you get a natural looking image or a "grungy" one.

I very seldom use HDR, because I generally feel that the DR of todays cameras is ample.

Check out these articles describing the use of HDR mapping on a single RAW image.

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/63-lot-of-info-in-a-digital-image

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/61-hdr-tone-mapping-on-ordinary-image

There was a good discussion around the issue here on LuLa forums: http://www.luminous-landscape.com/forum/index.php?topic=60082.0

Check this PDF by "leuallen" describing tone mapping in SNS HDR: https://docs.google.com/file/d/0B8ETvhCd81aFMTUyMTU4OTctZGQxZS00NTBmLWE5MDgtMDIwNWM1ODA3M2I4/edit?pli=1

Best regards
Erik

Trying to get a handle on HDR as I have little to no experience on this topic.

Given that an images max DR is restricted by pure black at one end and white at the opposite, am I correct that putting a "scene" (by way of multiple image exposed differently) through the HDR process only results in finer levels of tone? In other words, it doesn't make the ruler any longer, it just divides the ruler into finer increments? Presumably, this is impacted by the DR of the medium (i.e. monitor, print etc) as well.

Or, if a camera sensor is capable of say, twelve stops, can HDR actually result in an image that is, say, thirteen stops (so the ruler actually lengthens)? And if this is the case, what is the limit?

Have tried reading up on this subject, but so far it's a bit unclear.

Marv
Title: Re: HDR
Post by: hjulenissen on November 14, 2012, 04:06:35 am
Marketing material from a HDR display:
(http://images.bit-tech.net/content_images/2005/10/brightside_hdr_edr/luminance.jpg)

The ruler really is endless.
Title: Re: HDR
Post by: marvpelkey on November 14, 2012, 10:26:49 pm
Thank you both for very detailed and informative answers.

Marv
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 05:00:04 pm
More important, imo, than how much detail can be retained at the extreme ends of the shadows and highlights in an HDR composite is how it changes the appearance of the scene photographed. By averaging out the luminance of a scene, HDR tends to destroy any unique quality of the light that may have been captured by a single exposure. For that reason, HDR tends to, but not always, look rather manipulated and artificial. It's the main reason I never use it.
Title: Re: HDR
Post by: Tony Jay on December 04, 2012, 05:40:26 pm
More important, imo, than how much detail can be retained at the extreme ends of the shadows and highlights in an HDR composite is how it changes the appearance of the scene photographed. By averaging out the luminance of a scene, HDR tends to destroy any unique quality of the light that may have been captured by a single exposure. For that reason, HDR tends to, but not always, look rather manipulated and artificial. It's the main reason I never use it.

Can't completely agree with this statement.
One can make HDR look terrible and 'manipulated'.
I use HDR for the opposite purpose very successfully and have posted HDR images (with huge DR in the captured scene) on this forum that were not picked as HDR images until I fessed up - that is successful HDR (for me) - the finished product look just like it should.

Using 32-bit TIFF files in Lightroom to do the tonal manipulation has dramatically simplified the whole process of achieving natural looking results.

Tony Jay
Title: Re: HDR
Post by: KeithR on December 04, 2012, 06:35:31 pm
HDR can be either real good or real bad. It's all subjective.
Here's a link to an architectual photographer that uses HDR and gets great results without going over the top. I have no connection to him but saw his work and comments about his use of HDR on another forum.
http://www.larryandersonphotography.com/
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 07:56:41 pm
HDR can be either real good or real bad. It's all subjective.
Here's a link to an architectual photographer that uses HDR and gets great results without going over the top. I have no connection to him but saw his work and comments about his use of HDR on another forum.
http://www.larryandersonphotography.com/

I agree that Anderson's work is some of the best examples of HDR around. It's very clean, professional work. The quality of light, however, especially in the outdoor shots still looks homogenized to me. For indoor architectural or commercial work I can see that that wouldn't necessarily be a problem--maybe even an advantage in many instances. But for fine art landscape photography, preserving the subtle quality of light in the scene is important, at least to me.
Title: Re: HDR
Post by: Slobodan Blagojevic on December 04, 2012, 08:37:30 pm
Off-topic: is this the good, old "popnresh" reborn or indeed a brand new newbie?

Inquiring minds want to know :)
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 10:22:56 pm
Off-topic: is this the good, old "popnresh" reborn or indeed a brand new newbie?

Inquiring minds want to know :)

I'm new here. I take it there used to someone else with this alias. They must not be around any longer otherwise I assume I wouldn't have been able to register it.
Title: Re: HDR
Post by: Schewe on December 04, 2012, 10:41:10 pm
I'm new here. I take it there used to someone else with this alias.

Not for nothing but most people sign on to LuLa with something resembling a real name (notice the other screen names in the thread). You tend to be taken just a bit more seriously than trying to hide behind an anonymous screen name. If nothing else, at least sign your posts with a first name cause calling you "popnfresh" is pretty stupid. What, are you a baker?
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 10:48:21 pm
Not for nothing but most people sign on to LuLa with something resembling a real name (notice the other screen names in the thread). You tend to be taken just a bit more seriously than trying to hide behind an anonymous screen name. If nothing else, at least sign your posts with a first name cause calling you "popnfresh" is pretty stupid. What, are you a baker?

Not my concern. And, no. I work in IT.
Title: Re: HDR
Post by: Schewe on December 04, 2012, 10:49:52 pm
Not my concern.

Actually it should be if you want to fit in here...if not, you prolly won't he around long. Just sayin'
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 10:57:38 pm
Actually it should be if you want to fit in here...if not, you prolly won't he around long. Just sayin'

Are you like the forum police or something?
Title: Re: HDR
Post by: Schewe on December 04, 2012, 11:03:02 pm
Are you like the forum police or something?

Sometimes...yes. If you don't know who I am, I guess you don't really know much about LuLa, huh? You sure you wanna hang out here?
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 11:04:26 pm
Sometimes...yes. If you don't know who I am, I guess you don't really know much about LuLa, huh? You sure you wanna hang out here?

I think you seriously need to chill out.
Title: Re: HDR
Post by: Schewe on December 04, 2012, 11:08:26 pm
I think you seriously need to chill out.

And, I think you need to introduce yourself to the group...again, what are you, a baker?

Just so you know, it's useful if newbies get to know the community before launching themselves as some sort of expert. If you hang behind an anonymous screen name, it says something about you. Who are you and what credence do you deserve? LuLa is just like any other community...it keeps a sharp eye on newbies and how they respond and behave. Considering you joined yesterday, so far you don't have much of a track record (although your posts have generally been useful).
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 11:11:29 pm
And, I think you need to introduce yourself to the group...again, what are you, a baker?

Just so you know, it's useful if newbies get to know the community before launching themselves as some sort of expert. If you hang behind an anonymous screen name, it says something about you. Who are you and what credence do you deserve? LuLa is just like any other community...it keeps a sharp eye on newbies and how they respond and behave.

I'm not the one having behavioral issues at the moment. I was having an interesting conversation with others on this thread and suddenly you appear out of nowhere and you're all over my ass about my alias. I mean, seriously, what is your problem, dude?
Title: Re: HDR
Post by: Schewe on December 04, 2012, 11:49:08 pm
I mean, seriously, what is your problem, dude?

Who are you? And why are you here? It makes a difference doooode...introduce yourself (or don't and that will be telling).
Title: Re: HDR
Post by: popnfresh on December 04, 2012, 11:53:12 pm
Who are you? And why are you here? It makes a difference doooode...introduce yourself (or don't and that will be telling).

This may come as a shock, but I don't answer to you.
Title: Re: HDR (Getting back to the issue)
Post by: ErikKaffehr on December 04, 2012, 11:57:30 pm
Hi,

Just an idea. If you use LR 4.x you could try to open several images using "Merge to HDR Pro in Photoshop" but not doing tone mapping in photoshop but just saving the 32bit/channel image. As far as I recall you can open the image in LR and doing your tone mapping with LR-s controls which may be much better than the tools in photoshop.

Best regards
Erik

Trying to get a handle on HDR as I have little to no experience on this topic.

Given that an images max DR is restricted by pure black at one end and white at the opposite, am I correct that putting a "scene" (by way of multiple image exposed differently) through the HDR process only results in finer levels of tone? In other words, it doesn't make the ruler any longer, it just divides the ruler into finer increments? Presumably, this is impacted by the DR of the medium (i.e. monitor, print etc) as well.

Or, if a camera sensor is capable of say, twelve stops, can HDR actually result in an image that is, say, thirteen stops (so the ruler actually lengthens)? And if this is the case, what is the limit?

Have tried reading up on this subject, but so far it's a bit unclear.

Marv
Title: Re: HDR
Post by: dmerger on December 05, 2012, 12:07:40 am
Uh … welcome to the forum, popnfresh.  ::)
Title: Re: HDR
Post by: popnfresh on December 05, 2012, 12:12:34 am
Uh … welcome to the forum, popnfresh.  ::)

Thank you. Pleased to be here, mostly.

You may call me Doug.
Title: Re: HDR
Post by: Schewe on December 05, 2012, 01:11:43 am
You may call me Doug.

Ah, goodie, a name at last...(wasn't so hard, was it?)
Title: Re: HDR
Post by: popnfresh on December 05, 2012, 01:13:54 am
Ah, goodie, a name at last...(wasn't so hard, was it?)

What goes around, comes around.
Title: Re: HDR
Post by: michael on December 05, 2012, 09:02:43 am
Jeff, is right, we prefer real names here, not pseudonyms.

As to who Jeff is, yes, he is the police.  :)

Actually he's one of the world's recognized authorities on digital imaging, a consultant to Adobe, author of numerous books on the topic, and co-presenter of many of our LuLa training videos.

He's also a friend, a very large and agressive appearing guy (also a pussycat), drives a motocycle, and you'd rather have him on your side than against you.

Michael
Title: Re: HDR (Getting back to the issue)
Post by: RFPhotography on December 05, 2012, 10:03:29 am
Hi,

Just an idea. If you use LR 4.x you could try to open several images using "Merge to HDR Pro in Photoshop" but not doing tone mapping in photoshop but just saving the 32bit/channel image. As far as I recall you can open the image in LR and doing your tone mapping with LR-s controls which may be much better than the tools in photoshop.

Best regards
Erik


Not necessarily better, just different.  What is better for one may not be for another.  It's easier to get a more 'natural' result doing tonemapping with LR, although that can certainly be done in PS as well.

I think it was LR 4.1 that allowed editing of some 32 bit images.  Some means only 32 bit TIFF files.  LR still - with many people tapping their feet like Sonic the hedgehog waiting - can't catalogue or work with .exr or .hdr files.  The downside to TIFF is that the files are significantly larger than the other 32 bit file types.
Title: Re: HDR
Post by: popnfresh on December 05, 2012, 11:20:40 am
Jeff, is right, we prefer real names here, not pseudonyms.


If you allow people to register for this site using only pseudonyms, you should not hold it against them for going by them. Perhaps it's time to update your registration requirements.
Title: Re: HDR
Post by: john beardsworth on December 05, 2012, 12:34:04 pm
If you allow people to register for this site using only pseudonyms, you should not hold it against them for going by them. Perhaps it's time to update your registration requirements.
So true.
Title: Re: HDR
Post by: alanb on December 05, 2012, 01:05:27 pm
Let's remember that Schewe does have a hell of a sense of humor although he does seem a bit tough at times (he's really not).  It remains that it is probably better if he likes you since he probably has more knowledge of LR than anyone else here much of which he contrbutes free.  Unfortunately we must sometimes pay for it but his books are well worth the cost as they border on necessary.  Why not have fun  here?

Alan
Title: Re: HDR
Post by: dmerger on December 05, 2012, 01:50:17 pm
Doug, a lot of people use pseudonyms on this forum.  So, I wondered why Schewe singled you out to call stupid just for using a pseudonym.  Then I read Michael’s defense of Schewe’s rude behavior, and noted Michael’s strange reference to Schewe’s appearance.  I always thought that Schewe looked more like the Pillsbury Doughboy.   Then it hit me.  Doug, it’s your pseudonym  --  popnfresh --  that’s the Pillsbury Doughboy’s name!  Your unwitting use of popnfresh as your pseudonym evidently hit a raw nerve with Schewe.  ;)
Title: Re: HDR
Post by: popnfresh on December 05, 2012, 02:11:14 pm
Doug, a lot of people use pseudonyms on this forum.  So, I wondered why Schewe singled you out to call stupid just for using a pseudonym.  Then I read Michael’s defense of Schewe’s rude behavior, and noted Michael’s strange reference to Schewe’s appearance.  I always thought that Schewe looked more like the Pillsbury Doughboy.   Then it hit me.  Doug, it’s your pseudonym  --  popnfresh --  that’s the Pillsbury Doughboy’s name!  Your unwitting use of popnfresh as your pseudonym evidently hit a raw nerve with Schewe.  ;)

I like LuLa and I think Michael is one of the good guys. But I think if he expects people to use their real name rather than a pseudonym, he needs to make that clear when people sign up. Personally, if this were my site, I would probably insist that people register with their real names, even if only their pseudonym appears on their forum posts, just to have their real name on file. There's something to be said for insisting on real names to ensure that people are accountable for their conduct online. However, as someone who deals with internet security issues daily, I'm not going to dole out personal information to strangers if I don't have to, especially if everyone else on this site isn't required to.
Title: Re: HDR
Post by: hjulenissen on December 05, 2012, 02:44:14 pm
Sometimes...yes. If you don't know who I am, I guess you don't really know much about LuLa, huh? You sure you wanna hang out here?
I dont care how much of an expert you are, this comment is not a good way to wish people welcome.

-h

-welcome to the internet, the place where men are men, women are women, and little girls are FBI agents.
Title: Re: HDR
Post by: Schewe on December 05, 2012, 03:24:00 pm
Doug, it’s your pseudonym  --  popnfresh --  that’s the Pillsbury Doughboy’s name!  Your unwitting use of popnfresh as your pseudonym evidently hit a raw nerve with Schewe.

Yeah, that's pretty funny bud...not terribly accurate (I'm going more for the older Orson Welles look) but funny. I'll remember that one...
Title: Re: HDR (Gentlemen, may I please remind you?!)
Post by: ErikKaffehr on December 05, 2012, 03:43:41 pm
The original posting was about HDR by someone genuinely interested in HDR. If you need to discuss pseudonyms, anonymity or the forum terrier please start a new thread! It doesn't belong here!

Best regards
Erik

Yeah, that's pretty funny bud...not terribly accurate (I'm going more for the older Orson Welles look) but funny. I'll remember that one...
Title: Re: HDR
Post by: Peter_DL on December 05, 2012, 04:13:15 pm

HDR is really a two step process:

1) You combine several images into a HDR image

2) You "tone map" the image so it can be presented on a device with a normal dynamic range.

... I very seldom use HDR, because I generally feel that the DR of todays cameras is ample.

Many images as captured are indeed HDR relative to the designated output device,
and therefore call for HDR-typical tone mapping techniques (spatially non-uniform, as opposed to curves).

Some people prefer to use the term "HDR" only when two or more captures are combined,
although this niche is getting smaller with the advancing sensor technology and increasing camera DR - particularly in relation to a print.

Some further reading for the OP:
http://wwwimages.adobe.com/www.adobe.com/products/photoshop/family/prophotographer/pdfs/pscs3_renderprint.pdf

Peter

--
Title: Re: HDR
Post by: hjulenissen on December 05, 2012, 04:21:58 pm
I do also believe that the concept of "tonemapping" will simply be swallowed by the increasingly sophisticated non-linear, space-variant, signal adaptive exposure/contrast/... settings of standard raw developers.

Then it is only a question of "do I need one or more exposures to capture this scene sufficiently?". Hopefully, future camera sensors will allow us to use a single exposure for most interesting scenes.

-h
Title: Re: HDR
Post by: ErikKaffehr on December 05, 2012, 04:32:41 pm
Hi,

I agree, having written two small articles on the issue:

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/61-hdr-tone-mapping-on-ordinary-image

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/63-lot-of-info-in-a-digital-image

Best regards
Erik


Many images as captured are indeed HDR relative to the designated output device,
and therefore call for HDR-typical tone mapping techniques (spatially non-uniform, as opposed to curves).

Some people prefer to use the term "HDR" only when two or more captures are combined,
although this niche is getting smaller with the advancing sensor technology and increasing camera DR - particularly in relation to a print.

Some further reading for the OP:
http://wwwimages.adobe.com/www.adobe.com/products/photoshop/family/prophotographer/pdfs/pscs3_renderprint.pdf

Peter

--
Title: Re: HDR
Post by: LKaven on December 09, 2012, 07:00:09 am
It's worth mentioning that the HDRI Handbook, Second Edition, by Christian Bloch, is hitting the shelves this month (12/22/12).  The revision is comprehensive and brings things very much up-to-date. 
Title: Re: HDR
Post by: kirkt on December 09, 2012, 12:09:36 pm
It's worth mentioning that the HDRI Handbook, Second Edition, by Christian Bloch, is hitting the shelves this month (12/22/12).  The revision is comprehensive and brings things very much up-to-date. 

FYI Here is the table of contents:

http://www.hdrlabs.com/book/toc.html

kirk

Title: Re: HDR
Post by: Fine_Art on December 09, 2012, 02:19:18 pm
This may come as a shock, but I don't answer to you.

I think what is telling is Schewe's need to jump on a new guy at the forum. When I first got Photoshop I posted a question as a new member on their help forum. He jumped on me as a representative of that forum as well. Not surprisingly I have never bough another one of their products.

Maybe a real name is important to someone who tries to make a living off the industry, who therefore tries to cultivate an 'image' no pun intended. For many people photography, along with any associated forums, are for enjoyment during downtime. Projecting your desires for personal recognition onto others is misguided.
Title: Re: HDR
Post by: marvpelkey on December 09, 2012, 09:15:14 pm
Thanks everyone for the added comments, information and links to some good reading. Am currently going through some of the articles.

Marv
Title: Re: HDR
Post by: popnfresh on December 10, 2012, 11:15:40 am
I think what is telling is Schewe's need to jump on a new guy at the forum. When I first got Photoshop I posted a question as a new member on their help forum. He jumped on me as a representative of that forum as well. Not surprisingly I have never bough another one of their products.

Maybe a real name is important to someone who tries to make a living off the industry, who therefore tries to cultivate an 'image' no pun intended. For many people photography, along with any associated forums, are for enjoyment during downtime. Projecting your desires for personal recognition onto others is misguided.

Hopefully, we can all move on and focus on the kinds of discussions that make this forum worth visiting.
Title: Re: HDR
Post by: Peterretep on February 27, 2013, 12:43:04 pm
HDR can be either real good or real bad. It's all subjective.
Here's a link to an architectual photographer that uses HDR and gets great results without going over the top. I have no connection to him but saw his work and comments about his use of HDR on another forum.
http://www.larryandersonphotography.com/
Of course what we consider great looking photography is subjective and I'll agree with you only to a small degree Keith regarding the photographer you linked to. The small degree that I agree with is that his use of HDR is not over the top. However, to me many of his images are still very noticeable as relying on HDR technology for their creation in post processing. It's most noticeable to me in attention drawing over saturation in parts of an image that shouldn't be so vibrant and overall flatness tending to make his interiors, more so than his exteriors, unreal looking. Relying on software in post rather than lighting on location is a shortcut that largely determines the quality of the final image. Though his photos are not over the top HDRwise I think his use of HDR doesn't make for a better image which would be better achieved through more time and work on location. His is more of a quantity over quality formula. On the other end of the spectrum are photographers who will spend a day or longer lighting one interior, I'm somewhere in between the two approaches. I'll use HDR occasionally but you would be very hard pressed to identify those images as I do my best to eliminate any HDR look.

Peter
Title: Re: HDR
Post by: RFPhotography on February 27, 2013, 01:58:36 pm
If you can find clients who are prepared to pay for an entire day to shoot one interior, that's great.  With an increasing number of potential clients using the 'it's good enough' concept and doing it themselves with a mid-level DSLR, finding ways to reduce costs and survive is what many photographers have to do now.
Title: Re: HDR
Post by: Peterretep on February 27, 2013, 02:27:49 pm
Bob, what you say is true. It's a situation which has been exacerbated by the economy we have been in for a few years. It is more difficult to survive in today's market and HDR is a tool used by many seasoned pros and amateurs with a DSLR attempting to achieve that survival. But you also have to consider that reliance on HDR software is not going to put much distance between your photography and the competition's. How will that affect your long term survival? To what degree are you willing to compromise the quality of your photography?
Keep in mind the quote you have by Connolly.

 
Title: Re: HDR
Post by: RFPhotography on February 27, 2013, 03:06:57 pm
I guess it depends on how much of a compromise it's considered to be or whether it's considered a compromise at all.  You do.  Others don't.  Or at least, others don't to the extent you do.  If being able to save time and produce an end result that the client is happy with, or more than just happy with, means getting a job or not then the decision isn't overly difficult.  If one is in the enviable position of being able to turn down work, then it's a different matter.  As before; however, many aren't.  For many it's adapt or die.  Some would consider overexposed, blown out windows a compromise.  Others wouldn't.  Horses for courses.
Title: Re: HDR
Post by: bwana on February 28, 2013, 04:09:47 pm
Sry to revive a dying thread but I like the analogy of DR to a ruler. I always envisioned increasing dr as increasing the divisions between white and black. I do not see how increasing dr in the captured image 'makes the ruler longer'. Black is 0 and white is at the maximum (determined by the number of bits we are using to represent each shade. ) I have used a more traditional numerical representation using decimals to understand dr (wrongly?). a single digit to the right of a decimal would indicate 10 shades, two decimals - 100 shades, etc. 'Out of gamut warnings' can be understood in this context as a color with more decimal places than a monitor or printer was using. Rendering intent can also be understood in this context as truncating the extra decimal places so that the number representing the shade has the same decimal places as the display (Perceptual rendering intent rounds the number representing the shade towards the middle. colorimetric intent doesnt do any rounding - it just omits the shades which have more decimal places than the display.)

however when we speak of the dr of a display, we are discussing both- the number of shades it can display as well as how red is the red, how green is the green and how blue is the is the blue. When we are using a colored filter over a white light sources as in LCD displays, do we have pure red green and blue pixels? or is the red pixel when looked at under a spectroscope actually a bunch of close frequencies? When plotted in colorspace ( a triangle whose vertices are pure red blue and green) the colors of 'impure' pixels lie inside the triangle. Soon though, our displays may consist of precisely tuned laser diodes that emit a pure single frequency of red blue and green. Then the 'length of the dr ruler' for that display will be the maximum. Increasing dr will then consist of finer gradations only?
Title: Re: HDR
Post by: Guillermo Luijk on March 02, 2013, 05:08:23 am
Sry to revive a dying thread but I like the analogy of DR to a ruler. I always envisioned increasing dr as increasing the divisions between white and black. I do not see how increasing dr in the captured image 'makes the ruler longer'.

You don't see it because you fail to understand why several captures are needed. It is not a matter of number of divisions, it is a matter of noise.

In a single capture divisions run from 0 to the end of the ruler, but all those levels close to 0 (which correspond to deep shadows in the real world scene) are ruined because of noise. Making extra shots with higher exposure levels will blow highlights but will shift those dark areas to noisefree areas of the sensor. Finally your favourite HDR program blends all together, taking each part of the scene from the appropiate captured RAW files (highlights from the lowest exposure, dark shadows from the most exposed files).

Number of levels is not the reason for multiexposure in the HDR process, they are just a consequence. Noise is the reason. Once DR of sensors reach high enough performance, multiexposure will be unnecesary and HDR photographers will shoot just once. But the tone mapping process and techniques will still be necessary to accomodate in a natural looking way captured information (now from a single input file) into the limited DR output devices (print, screen, projector).
Title: Re: HDR
Post by: David Eichler on March 10, 2013, 04:42:44 am
Bob, what you say is true. It's a situation which has been exacerbated by the economy we have been in for a few years. It is more difficult to survive in today's market and HDR is a tool used by many seasoned pros and amateurs with a DSLR attempting to achieve that survival. But you also have to consider that reliance on HDR software is not going to put much distance between your photography and the competition's. How will that affect your long term survival? To what degree are you willing to compromise the quality of your photography?
Keep in mind the quote you have by Connolly.

 

Exactly.  And, by the way, I think a lot of people use HDR for interior photography especially because they don't have any real lighting or Photoshop skills and they are looking for a process that seems easy. So, it is not necessarily always because people are making a choice to compromise. They simply don't have the skills to achieve high quality results.