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DPChallenge Forums >> Photography Discussion >> HDR > < or =Tone Mapping Huh?
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12/18/2006 12:45:33 PM · #1
Ok I am still rather undecided on if I even like this new craze, but I am having a hard time understanding it also. From what I gather, HDR and Tone Mapping are NOT the same thing. But are they not both done by merging multiple images? If so, what is the difference? What constitutes tone mapping, and what constitutes HDR? Where is ' . substr('//www.dpchallenge.com/images/user_icon/21.gif', strrpos('//www.dpchallenge.com/images/user_icon/21.gif', '/') + 1) . ' Bear_Music? I bet he could shed some light on this for me.

My head hurts...
12/18/2006 12:50:56 PM · #2
Hee hee, I'm a poor "bear substitute" but I'll try. You might say I'm the "bear minimum..."
HDR is defined as an image that has very high diynamic range, usually 16 bits/channel or more. It is usually accomplished by combining several differently-exposed 8 bit/channelimages. Tonemapping is a necessary part of displaying a HDR image in a space that does not accommodate the full dynamic range of the final image.
A single RAW file may be considered HDR, since it can have up to 10 stops of information (most use 12 bits/channel in a 16-bit space). If a RAW file (or 16 bit/channel TIFF) is imported to an HDR processing application like Photomatix, the tonemapping function can be applied to the single RAW image. The effects can be dramatic, or so subtle that it's almost impossible to tell that tonemapping has been done.

Message edited by author 2006-12-18 12:54:07.
12/18/2006 01:01:03 PM · #3
Speaking...

True HDRI imaging involves taking multiple, differently exposed versions of the same image and then combining them into a single, high dynamic range image. This image will neither display nor print properly because it far exceeds the tonal range of either screen or paper. Tone mapping is the next step in true HDRI, where the extremes are "mapped" selectively closer to the midrange so they will display/print. The current basic/advanced rulesets do not permit true HDRI imaging. The new expert ruleset does.

This is a true HDRI image, in a special challenge that allowed it:

' . substr('//images.dpchallenge.com/images_challenge/586/thumb/426376.jpg', strrpos('//images.dpchallenge.com/images_challenge/586/thumb/426376.jpg', '/') + 1) . '

Quasi HDRI imaging involves taking a single RAW exposure and producing differently exposed "versions" of it in the RAW processor, then combining them and tone mapping them as above. It doesn't allow the extreme compensation that true HDRI does, but it is legal in the advanced ruleset.

This is a quasi HDRI Image in an advanced challenge:

' . substr('//images.dpchallenge.com/images_challenge/551/thumb/396120.jpg', strrpos('//images.dpchallenge.com/images_challenge/551/thumb/396120.jpg', '/') + 1) . '

It is also possible to take a single 16-bit TIFF image and tone map directly off of it. This can be used to great advantage with some images, and it can also be wildly exaggerated. Tone mapping is currently legal in basic challenges, and it can be approximated with aggressive use of the shadow/highlight tool in CS2.

These are tone mapped images with no HDRI component, the first from an advanced challenge and the second and third from basic challenges:

' . substr('//images.dpchallenge.com/images_challenge/597/thumb/436890.jpg', strrpos('//images.dpchallenge.com/images_challenge/597/thumb/436890.jpg', '/') + 1) . ' ' . substr('//images.dpchallenge.com/images_challenge/589/thumb/429815.jpg', strrpos('//images.dpchallenge.com/images_challenge/589/thumb/429815.jpg', '/') + 1) . ' ' . substr('//images.dpchallenge.com/images_challenge/595/thumb/434679.jpg', strrpos('//images.dpchallenge.com/images_challenge/595/thumb/434679.jpg', '/') + 1) . '

It's kind of like any other tool, this HDRI/Tone Mapping business; they can be used very "naturally" or they can be wildly exaggerated. We are seeing quite a few wild exaggerations in DPC right now, but there are a lot of images using these techniques that go unremarked because it's not obvious what was done.

Robt.

Message edited by author 2006-12-18 13:02:37.
12/18/2006 01:10:33 PM · #4
(So if I have this right) To do tone mapping, you just take a few different exposure, layer them, and and merge the best exposed areas to get the best over all image? Such as using filter and dodging and burning in a traditional darkroom? Or am I still way off?

Message edited by author 2006-12-18 13:10:56.
12/18/2006 01:29:59 PM · #5
Originally posted by kirbic:

Hee hee, I'm a poor "bear substitute" but I'll try. You might say I'm the "bear minimum..."

reminded me of this joke:
(from just for some laughs thread
Originally posted by scrum8:

A bear walks into a bar in Billings, Montana and orders a beer.
The bartender says, we don't serve beer, to bears, in bars, in Billings, Montana.
The bear says, "if you don't serve me, I'm going to eat that lady at the end of the bar."
The bartender refuses and the bear goes to the end of the bar and swallows the woman whole.
The bear then comes back to the bartender and again orders a beer.
The bartender replied that we don't serve beer, to bears, in bars, on drugs, in Billings, Montana. The bear says, what do mean, "on drugs"?
The bartender says, "that was a bar-bitch-you-ate"
12/18/2006 01:36:44 PM · #6
I just took my current entry and ran it through tonal mapping in Photomatix. All I did different was:
1. took the same RAW converted to 16-bit tiff
2. Loaded it up in Photomatix
3. Run tonal mapping
4. Saved
5. Opened PS/CS and auto Levels and manual curves.
6. Save for web.

And the image is 100% better than my entry IMO. WoW I wish I would of had that program before I entered the challenge. I know it would of added .5 to 1.0 points to my score, at least I think so.
12/18/2006 01:42:19 PM · #7
Originally posted by breadfan35:

(So if I have this right) To do tone mapping, you just take a few different exposure, layer them, and and merge the best exposed areas to get the best over all image? Such as using filter and dodging and burning in a traditional darkroom? Or am I still way off?


NO.

Tone mapping does not require multiple exposures and sandwiching of same. You can tone map off a single exposure and enhance local area contrast in both the shadows and the highlights.

However, if you do "true" or "quasi" HDRI imaging (from multiple images or multiple variations of a single exposure, respectively) then you will have to run Tone Mapping to finish the job.

R.
12/18/2006 01:47:13 PM · #8
Originally posted by Southern Gentleman:

I just took my current entry and ran it through tonal mapping in Photomatix. All I did different was:
1. took the same RAW converted to 16-bit tiff...


FWIW, no need to convert first, Photomatix shoild read the RAW file just fine :-)
12/18/2006 01:51:11 PM · #9
Originally posted by kirbic:

Originally posted by Southern Gentleman:

I just took my current entry and ran it through tonal mapping in Photomatix. All I did different was:
1. took the same RAW converted to 16-bit tiff...


FWIW, no need to convert first, Photomatix should read the RAW file just fine :-)


Yeah, that's actually true, as I've discovered; but on my slow machine it takes a LOT longer to work on the RAW image, plus I can't open RAW in PS7 anyway, so I need a TIFF from RAW for that, so I just process RAW to TIFF as a matter of course right now.

R.
12/18/2006 02:12:52 PM · #10
Originally posted by kirbic:

Tonemapping is a necessary part of displaying a HDR image in a space that does not accommodate the full dynamic range of the final image.


One thing to note is an HDR image can be converted to a low dynamic range many different ways. One way is with Photomatix but Photoshop CS2 gives you other choices like Exposure & Gamma, Highlight Compression, Equalize Histogram and Local Adaption. So depending on what is chosen you will get different results.
12/18/2006 02:19:25 PM · #11
Here's a few of mine from this week...
12/18/2006 02:22:13 PM · #12
Originally posted by Gauti:

Originally posted by kirbic:

Hee hee, I'm a poor "bear substitute" but I'll try. You might say I'm the "bear minimum..."

reminded me of this joke:
(from just for some laughs thread
Originally posted by scrum8:

A bear walks into a bar in Billings, Montana and orders a beer.
The bartender says, we don't serve beer, to bears, in bars, in Billings, Montana.
The bear says, "if you don't serve me, I'm going to eat that lady at the end of the bar."
The bartender refuses and the bear goes to the end of the bar and swallows the woman whole.
The bear then comes back to the bartender and again orders a beer.
The bartender replied that we don't serve beer, to bears, in bars, on drugs, in Billings, Montana. The bear says, what do mean, "on drugs"?
The bartender says, "that was a bar-bitch-you-ate"


Nice one.
12/18/2006 02:48:53 PM · #13
So tone mapping is an action or a function that you run a photo through much like a filter in photoshop? By that I mean it is something applied at one time, not multiple things done over sometime (few minutes or so)?

I guess this is what I am confused about, I don't know what the process of "tone mapping" is. I had thought it was like I said, merging multiple photos, but I'm obviously wrong. Is there a "tone mapping" tab in photomaitx or something?

My head still hurts...

Message edited by author 2006-12-18 14:52:39.
12/18/2006 02:53:18 PM · #14
Originally posted by breadfan35:

So tone mapping is an action or a function that you run a photo through much like a filter in photoshop? By that I mean it is something applied at one time, not multiple things done over sometime (few minutes or so)?

I guess this is what I am confused about, I don't know what the process of "tone mapping" is. I had thought it was like i said, merging multiple photos, but I'm obviously wrong. is there a "tone mapping" tab in photomaitx or something?

My head still hurts...


You can use tone mapping as an "effects" filter on a non-HDR image or you can use it for what it was designed for that is to convert an HDR image into a tonal range that most monitors can display. HDR, high dyanmic range produces so much data that most monitors cannot fully display it hence the need to convert it to low dynamic range. Tone mapping allows you to do that.
12/18/2006 02:53:23 PM · #15
Originally posted by breadfan35:

So tone mapping is an action or a function that you run a photo through much like a filter in photoshop? By that I mean it is something applied at one time, not multiple things done over sometime (few minutes or so)?

I guess this is what I am confused about, I don't know what the process of "tone mapping" is. I had thought it was like i said, merging multiple photos, but I'm obviously wrong. is there a "tone mapping" tab in photomaitx or something?

My head still hurts...


Yes, that's correct. Tone mapping is a filter of sorts, an action of sorts, you get a dialogue screen and fiddle with the variables. Here's a screen shot of Photomatix tone mapping in action, exaggerated example for purposes of illustration:

' . substr('//images.dpchallenge.com/images_portfolio/30861/thumb/417403.jpg', strrpos('//images.dpchallenge.com/images_portfolio/30861/thumb/417403.jpg', '/') + 1) . '

One problem with tone mapping on a single exposure is it seems to muddy up light, even areas a lot. So sometimes I take the original, sanwich it over the tone mapped version, and set the blend mode to "lighten" so it restores brightness in those areas, then fade the overlay to whatever looks best. Not legal in basic though.

R.
12/18/2006 02:57:02 PM · #16
Originally posted by Bear_Music:

Originally posted by breadfan35:

So tone mapping is an action or a function that you run a photo through much like a filter in photoshop? By that I mean it is something applied at one time, not multiple things done over sometime (few minutes or so)?

I guess this is what I am confused about, I don't know what the process of "tone mapping" is. I had thought it was like i said, merging multiple photos, but I'm obviously wrong. is there a "tone mapping" tab in photomaitx or something?

My head still hurts...


Yes, that's correct. Tone mapping is a filter of sorts, an action of sorts, you get a dialogue screen and fiddle with the variables. Here's a screen shot of Photomatix tone mapping in action, exaggerated example for purposes of illustration:

' . substr('//images.dpchallenge.com/images_portfolio/30861/thumb/417403.jpg', strrpos('//images.dpchallenge.com/images_portfolio/30861/thumb/417403.jpg', '/') + 1) . '

One problem with tone mapping on a single exposure is it seems to muddy up light, even areas a lot. So sometimes I take the original, sanwich it over the tone mapped version, and set the blend mode to "lighten" so it restores brightness in those areas, then fade the overlay to whatever looks best. Not legal in basic though.

R.


Ahh, now I get it. Thank you so much Bear, and everyone in here who tried to help me understand. :-)
12/18/2006 03:10:38 PM · #17
The true beauty of HDR is to assemble several exposures to display what our eyes saw,
but our cameras could never reveal in a single click.

' . substr('//images.dpchallenge.com/images_portfolio/19708/thumb/440031.jpg', strrpos('//images.dpchallenge.com/images_portfolio/19708/thumb/440031.jpg', '/') + 1) . ' ' . substr('//images.dpchallenge.com/images_portfolio/19708/thumb/425284.jpg', strrpos('//images.dpchallenge.com/images_portfolio/19708/thumb/425284.jpg', '/') + 1) . '

12/18/2006 03:27:45 PM · #18
Sorry if this is a silly question, but I just started using CS2 and haven't figured out all the funtions yet. I've read that CS2 has an HDR tool/filter/function but I'm having a hard time finding it. Is there such a thing without having to purchase Photomatix and are they similar?
12/18/2006 03:33:44 PM · #19
Originally posted by jenesis:

Sorry if this is a silly question, but I just started using CS2 and haven't figured out all the funtions yet. I've read that CS2 has an HDR tool/filter/function but I'm having a hard time finding it. Is there such a thing without having to purchase Photomatix and are they similar?


It is under File/Automate/Merge to HDR.
12/18/2006 03:33:57 PM · #20
Originally posted by jenesis:

Sorry if this is a silly question, but I just started using CS2 and haven't figured out all the funtions yet. I've read that CS2 has an HDR tool/filter/function but I'm having a hard time finding it. Is there such a thing without having to purchase Photomatix and are they similar?


BradP's two examples are done with CS2. I don't think CS2 has a separate tone mapping function, but I don't have the program so I can't say for sure. Many who've tried both say Photomatix gives superior results, but for me it's the only game in town anyway.

R.
12/18/2006 03:36:55 PM · #21
Thanks to both of you. :-)
12/18/2006 03:40:24 PM · #22
The only thing I really haven't cared that much about in tone mapping/Photomatix, is the noise that is generated in the deeper shadows. A true HDR doesn't do that, and on large size images/prints, it becomes pretty noticeable.
12/18/2006 03:45:43 PM · #23
This brings up an interesting point btw; Photomatix has a whole OTHER set of tools that qualify as "merges", but HDRI (in Photomtaix at least) is a different thing, much more powerful. I started with an unlicensed version of Photomtaix so I could play with expanded tonal range via image merging, then paid for the full version to get access to true HDRI and tone mapping.

R.
12/18/2006 03:49:27 PM · #24
Originally posted by Bear_Music:

Originally posted by jenesis:

Sorry if this is a silly question, but I just started using CS2 and haven't figured out all the funtions yet. I've read that CS2 has an HDR tool/filter/function but I'm having a hard time finding it. Is there such a thing without having to purchase Photomatix and are they similar?


BradP's two examples are done with CS2. I don't think CS2 has a separate tone mapping function, but I don't have the program so I can't say for sure. Many who've tried both say Photomatix gives superior results, but for me it's the only game in town anyway.

R.


When you load or create an HDR image (.hdr) in photoshop it automatically puts you in 32 bit mode. When you go to Image/Mode/16 Bit you are then presented with a window that gives you several ways to "process" your HDR. Those options are Exposure and Gamma, Highlight Compression, Equalize Histogram and Local Adaption. The latter is the most useful I have found as it gives you a "tonal" curve to play with. Those are Photoshop's "tone mapping" options.

Message edited by author 2006-12-18 15:50:26.
12/18/2006 08:14:31 PM · #25
I dug out a some images that I shot with intent of doing HDR. I really did not like the results from CS2 but with all the HDR talk I started to play with them again...

I was so impressed with Photomatix I brought a copy.

' . substr('//images.dpchallenge.com/images_portfolio/33181/thumb/440121.jpg', strrpos('//images.dpchallenge.com/images_portfolio/33181/thumb/440121.jpg', '/') + 1) . '

This was shot at dawn on 9-11-05 and was 5 images 1/2 stop apart
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