'HDR' vs 'tone mapping'

[Shadowblade]

Just a quick rant - why do people insist on calling unrealistically tone-mapped photos generated from a single image 'HDR' or 'pseudo-HDR', or even associating unrealistically tone-mapped images generated from an HDR file with the HDR process, rather than the tone-mapping process?

HDR simply refers to combining several images, taken at different exposure settings but compositionally identical, to produce a single image with greater dynamic range than is possible with a single exposure. It is no more or less realistic in appearance than any other image, although, without further processing, it needs to be 'windowed' through different exposure values to see the highlights and shadows properly.

Every digital image - HDR or not - needs to be tone-mapped, otherwise it's just a string of 1s and 0s. It's in the curves setting of DPP or done automatically by the camera, and can be further modified in Photoshop using Curves, Levels and other tools, to give either realistic or unrealistic results, depending on the intent of the user, with either HDR or non-HDR images.

Associating unrealistic images with HDR (even when they're not HDR images) just gives HDR a bad name, particularly when it's such a good technique for producing completely-realistic images of scenes which could otherwise not be photographed in a single exposure, due to non-straight horizons and the like.

/rant

[wolfden]

I kinda raised something similar to this earlier:
Too Much HDR Confusion?
http://photography-on-the.net/forum/...d.php?t=843177

HDR and Tone Mapped images have just been lumped together. I have a feeling if you made two seperate forums, the HDR forum, which would be true HDRs, would hardly have any posts while the Tone Mapped one would have plenty. On other forums I don't see it questioned as much as I do here. I understand the view point, so should they be seperate forums?

[dugcross]

Originally Posted by wolfden

HDR and Tone Mapped images have just been lumped together. I have a feeling if you made two seperate forums, the HDR forum, which would be true HDRs, would hardly have any posts while the Tone Mapped one would have plenty. On other forums I don't see it questioned as much as I do here. I understand the view point, so should they be seperate forums?

I agree with that. The problem is that too many photographers still think their one exposure image is a HDR image. They refuse to listen to anybody and think that just because at the very least they created 2 more images in lightroom or whatever from that single image and took it through Photomatix that the image is HDR when it is not. It is just a tone-mapped image! If you start out with a single image, no matter what you do to it, it will STILL not be a HDR image, it is tone-mapped. Tone-mapping an image does not magically make it HDR.

[wolfden]

Originally Posted by dugcross

I agree with that. The problem is that too many photographers still think their one exposure image is a HDR image. They refuse to listen to anybody and think that just because at the very least they created 2 more images in lightroom or whatever from that single image and took it through Photomatix that the image is HDR when it is not. It is just a tone-mapped image! If you start out with a single image, no matter what you do to it, it will STILL not be a HDR image, it is tone-mapped. Tone-mapping an image does not magically make it HDR.

I agree, some where along the line HDR and Tone Mapped just got lumped together and now we have the confusion to deal with. I don't know the solution but to educate that there is a difference.

[dmccabe]

Many people still do not understand "dynamic range"... and even with two images, are not getting HDR.

And on the other hand, I have seen many single images tone mapped that look fantastic.

But the bottom line is people need to stop worry about "post" techniques... and only judge the final image... not how it got there.

When people ask me what tools I use, I reply the "expensive" ones... and my prices are going up, so you better buy now.

[Gary McDuffie]

As several of you guys know, we've discussed this until we were blue in the face in other threads. You also know that I don't object to either process. What I do object to is the high number of people calling what are simply overprocessed tonemapped images HDR. Even more, I object to the fact that many of them don't even know any better. People just keep posting stuff and calling it HDR, which misleads the newbies that come in and read each thread and get it into their head that they are.

[bunyarra]

Being fair to single image processing. With cameras like the 5DII in RAW, you do have significant detail lost at the extremes - the DR captured is greater than can be shown by one image processed normally.

Creating 3 separate images from one original RAW and putting that through the "HDR" process will generate an image that can accurately be classified as derived from a scene's high dynamic range. Though, most will agree, it is High(ish)

[dugcross]

Originally Posted by bunyarra

Creating 3 separate images from one original RAW and putting that through the "HDR" process will generate an image that can accurately be classified as derived from a scene's high dynamic range. Though, most will agree, it is High(ish)

The result of that process will be a tone-mapped image NOT a HDR image.

[bunyarra]

Originally Posted by dugcross

The result of that process will be a tone-mapped image NOT a HDR image.

I did not even mention the tone mapping.

Image #1 = -1/1.5 EV
Image #2 = 0 EV
Image #3 = +1/1.5 EV

This is the same as exposing 3 images with -1/0/+1 compensation. No matter how it is derived, when your image prior to tone mapping was created from images with more dynamic range than a single exposure can accomplish, you have created an HDR photo.

I do not argue that the range is less than you would ideally need.

[Shadowblade]

Originally Posted by bunyarra

I did not even mention the tone mapping.

Image #1 = -1/1.5 EV
Image #2 = 0 EV
Image #3 = +1/1.5 EV

This is the same as exposing 3 images with -1/0/+1 compensation. No matter how it is derived, when your image prior to tone mapping was created from images with more dynamic range than a single exposure can accomplish, you have created an HDR photo.

I do not argue that the range is less than you would ideally need.

It's not the same. You're only with the dynamic range available from a single exposure - just that one image has been pulled one stop and another has been pushed one stop. You can theoretically achieve exactly the same result with the curves function in Photoshop (or, since RAW is involved, by adjusting curves in DPP prior to RAW conversion) - you have mapped the shadows to be brighter than they previously were, and the highlights to be less so, but you have not actually created an image with greater dynamic range than that which was available in the original image. Essentially, it's just applying a custom curve to the image prior to RAW conversion, rather than a standard one.

[dugcross]

Originally Posted by bunyarra

This is the same as exposing 3 images with -1/0/+1 compensation.

NO this is not the same at all. Creating 3 images from one exposure does not create an HDR image. I don't care how you do it, it's only a tone-mapped image. You're not going to create information that is not there to begin with, with one exposure. If you don't have at least 3 separate exposures to begin with you DO NOT have a HDR image. Shadowblade is correct with his post.

[bunyarra]

Originally Posted by dugcross

NO this is not the same at all. Creating 3 images from one exposure does not create an HDR image. I don't care how you do it, it's only a tone-mapped image. You're not going to create information that is not there to begin with, with one exposure. If you don't have at least 3 separate exposures to begin with you DO NOT have a HDR image. Shadowblade is correct with his post.

ACR or D

Sorry - I don't care what the theory is, you still need to use ACR or DPP to create one pulled and one pushed image to retrieve the "hidden" RAW data. Try it for yourself. I do this every week.

And, for the record, 2 images is the minimum needed by your rules not 3

I don't want this to get heated or turn into a pissing contest. If you disagree with my definition of HDR, please do so. Don't presume I am wrong in my definition. My pre-tone-mapped images created from a single RAW file have a greater DR than you can create from PS/DPP/ACR in one go no matter how you manipulate curves, fill, recover.

I extract the absolute maximum from each end of the RAW file and need to use the 3 images in my workflow as the image degrades significantly away from the edges when you start significantly pushing/pulling.

Sorry you are militant in your HDR viewpoint - I'm not. I just want to create the best possible output for my customers I will defend what I do as creating high dynamic range images - you will disagree - and we all move on.

There is no right way to do anything in photography or post processing these days - the days of dictated methodologies has long gone, thank goodness.

If we are disagreeing over one term's interpretation, life is too short to bother

[_GUI_]

Originally Posted by dugcross

Creating 3 images from one exposure does not create an HDR image. I don't care how you do it, it's only a tone-mapped image. You're not going to create information that is not there to begin with, with one exposure. If you don't have at least 3 separate exposures to begin with you DO NOT have a HDR image. Shadowblade is correct with his post.

You are not going to create more information by doing several replicas at different exposure values of the same image or RAW file, but... who says a single image cannot contain _all_ the information of the scene?

BTW with just 2 exposures cleverly chosen you can capture noise free HDR scenes of 12 stops of dynamic range with any DSLR at ISO100, no 3 separate exposures needed. The number 3 just comes from the usual camera bracketing (typ. {-2,0,+2}), but it is not a definition nor requirement itself.

Regards

[Shadowblade]

Originally Posted by _GUI_

You are not going to create more information by doing several replicas at different exposure values of the same image or RAW file, but... who says a single image cannot contain _all_ the information of the scene?

BTW with just 2 exposures cleverly chosen you can capture noise free HDR scenes of 12 stops of dynamic range with any DSLR at ISO100, no 3 separate exposures needed. The number 3 just comes from the usual camera bracketing (typ. {-2,0,+2}), but it is not a definition nor requirement itself.

Regards

If it all comes from a single original, exposure, it's not HDR. If you're creating new 'exposures' by pushing and pulling in DPP/ACR, all you're really doing is adjusting the tone curves separately for each image, then combining them into a single, more complex tone curve - nothing you can't do by manually adjusting the curve for the RAW file in the first place.

HDR involves taking combining information available in one exposure but not the second, with information available in the second exposure but not the first, to create a new image containing information from both exposures. If you already had all the information in one exposure, you're not actually increasing the image's dynamic range - merely brightening the shadows and dimming the highlights.

[dugcross]

Originally Posted by bunyarra

I don't want this to get heated or turn into a pissing contest. If you disagree with my definition of HDR, please do so. Don't presume I am wrong in my definition. My pre-tone-mapped images created from a single RAW file have a greater DR than you can create from PS/DPP/ACR in one go no matter how you manipulate curves, fill, recover.

I extract the absolute maximum from each end of the RAW file and need to use the 3 images in my workflow as the image degrades significantly away from the edges when you start significantly pushing/pulling.

Sorry you are militant in your HDR viewpoint - I'm not. I just want to create the best possible output for my customers I will defend what I do as creating high dynamic range images - you will disagree - and we all move on.

I'm not making an argument over this either but simply put this is not my opinion but fact. A lot of people think you can pull more information out of one exposure and make multiple exposures of it thinking you're getting more information out of it. But the whole point of HDR is taking more exposures to get more information than you can get out of one exposures.

"High dynamic range (HDR) images enable photographers to record a greater range of tonal detail than a given camera could capture in a single photo. This opens up a whole new set of lighting possibilities which one might have previously avoided—for purely technical reasons. The new "merge to HDR" feature of Photoshop allows the photographer to combine a series of bracketed exposures into a single image which encompasses the tonal detail of the entire series." from http://www.cambridgeincolour.com/tut...amic-range.htm

"High-dynamic-range photographs are generally achieved by capturing multiple standard photographs, often using exposure bracketing, and then merging them into an HDR image. Digital photographs are often encoded in a camera's raw image format, because 8 bit JPEG encoding doesn't offer enough values to allow fine transitions (and also introduces undesirable effects due to the lossy compression)." http://en.wikipedia.org

"HDR Photography allows photographers to capture a greater range of tonal detail than any camera could capture thru a single photo." http://photocritic.org/hdr-photography-how-to/

I'm not saying that you can't get an HDR "look" from a single image as you are doing but the fact is the result is a faux HDR image or tone-mapped image.

Originally Posted by Shadowblade

HDR involves taking combining information available in one exposure but not the second, with information available in the second exposure but not the first, to create a new image containing information from both exposures. If you already had all the information in one exposure, you're not actually increasing the image's dynamic range - merely brightening the shadows and dimming the highlights.

Once again, I totally agree with you Shadowblade