HDR from single raw

[Alpha]

Despite what Max says, there is nothing to stop a single exposure, whether digital or chemical, from being an HDR image if the entire brightness range of the scene is within the native dynamic range of the sensitive medium. That is, in many ways, preferable to multi-exposure HDR.

Best,
Helen

I'm sorry but this is incorrect. As I've stated many times, HDR is fundamentally based upon extending the dynamic range of an image beyond what one captures with a single exposure. This is entirely regardless of what is technically possible to capture in a single exposure. If someone composites three exposures and produces a final image identical to what I capture with one, the composite is HDR and the single exposure is not. HDR is defined by the final image being beyond the dynamic range of an individual exposure. The technical concept of HDR is not based upon theoretical definitions of native sensitivity, but upon the end-result single exposure and its range. Extending that makes it HDR, regardless of whether or not that extension falls within the medium's native sensitivity.

 

[Arch]

Wow! I thought you guys would get it right away. The bottom one is the true HDR. The top was made from one raw.

The top image has the better dynamic range, therefore it IS the true HDR, either that OR you have deibaralty edited it badly so i'd guess wrong.... there is no way that one exposure can have a better dynamic range than a combination of different exposures. So what im saying is if i am wrong, then you made it look that way.

 

[Alpha]

The top image has the better dynamic range, therefore it IS the true HDR, either that OR you have deibaralty edited it badly so i'd guess wrong.... there is no way that one exposure can have a better dynamic range than a combination of different exposures. So what im saying is if i am wrong, then you made it look that way.

I think it's obvious that at the very least the highlight range is much better in the second.

 

[domromer]

The top image has the better dynamic range, therefore it IS the true HDR, either that OR you have deibaralty edited it badly so i'd guess wrong.... there is no way that one exposure can have a better dynamic range than a combination of different exposures. So what im saying is if i am wrong, then you made it look that way.

If I did it was unintentional. The pics are the same scene taken a few minutes apart. The light changed a lot. They were both tweaked in ps. So I guess it's not apples to apples since there is variables involved. Next time I post them same thing with both pics straight out of photomatix no PS tweaking at all.

 

[Arch]

I think it's obvious that at the very least the highlight range is much better in the second.

yes, but look at the blown out area of the snow... not to mention the blown out sky... this simply would not happen in a well processed HDR. The highlights are better in the second but im not saying the dynamic range is particulaly good in either if them... all i can say is the test doesn't really hold up if they are edited badly.

 

[domromer]

yes, but look at the blown out area of the snow... not to mention the blown out sky... this simply would not happen in a well processed HDR. The highlights are better in the second but im not saying the dynamic range is particulaly good in either if them... all i can say is the test doesn't really hold up if they are edited badly.

jeeze I didn't think my editing was that bad!

 

[Arch]

lol.... i didnt mean bad as in the image is bad (i actually quite like it) just 'uneven' editing then... i think given time you would have worked on the sky and blown out snow area, right?... your works good tho im not saying anything against it

 

[domromer]

Ok, I'll dry my tears now.

 

[Helen B]

I'm sorry but this is incorrect. As I've stated many times, HDR is fundamentally based upon extending the dynamic range of an image beyond what one captures with a single exposure. This is entirely regardless of what is technically possible to capture in a single exposure. If someone composites three exposures and produces a final image identical to what I capture with one, the composite is HDR and the single exposure is not. HDR is defined by the final image being beyond the dynamic range of an individual exposure. The technical concept of HDR is not based upon theoretical definitions of native sensitivity, but upon the end-result single exposure and its range. Extending that makes it HDR, regardless of whether or not that extension falls within the medium's native sensitivity.

Max,

Your definition of HDR sounds more like a definition of exposure blending. Where does your definition come from? An insistence on multiple exposures doesn't fit with the sense of HDR as I read in articles in things like the Journal of Imaging Science and Technology. To me, the essence of HDR imaging is the use of almost absolute (in terms of the range of human perception) luminance and chrominance, and the way that information is stored and displayed.

Best,
Helen

 

[Alpha]

I'm afraid you're confusing a few different things here. One does have to do with issues of luminance and chrominance and high bit-depth display and the like. These are theoretical engineering quandaries that are misplaced in this context. If the HDR to which I am referring were based solely on such qualities, none of the images we call HDR would truly be HDR because when push comes to shove they have normal 16-bit depth no matter how you hash it.

Given that, the only way to define HDR in our context is simple semantics. High Dynamic Range specifically implies that the dynamic range is higher than normal. Again, this has nothing to do with native sensitivity. Rather, it defines an HDR image as a composite image whose dynamic range is greater than the dynamic range of any of its parts.

And oooooh you read the Journal of Imaging Science and Technology. That's nice. Let's not get into a pissing contest, alright?

 

[Helen B]

Max,

" And oooooh you read the Journal of Imaging Science and Technology. That's nice. Let's not get into a pissing contest, alright?"

Why that snotty attitude? I didn't mention JIST as part of a pissing context. It seems fairly evident that you and I have different concepts of what HDR means, so I thought that some context was appropriate. I'm not mixing anything up, I just have a different viewpoint from your narrow (in my opinion) definition.

I'm not going to persuade you, and you aren't going to persuade me, so let's leave it at that. You can continue to promote your definition, and I'll continue to disagree with you. Is that OK with you?

Best,
Helen

 

[shorty6049]

its ok with me! ;-)

 

[Alpha]

I am not disputing what you've said about HDR, but whether it has any relevance to this discussion. My attitude is not snotty. Quite the contrary. I'm trying to clarify the practical terms of a technique that is discussed here regularly. I understand what definition you're citing perfectly well. But you are not providing any context for this discussion. Rather, you're starting off on an unrelated tangent that has far more to do with optics and theoretical engineering questions relating to bit depth, than you are participating helpfully in a discussion of a technique with a specific functional definition as far as this group of forum users is concerned. If there's any snottiness here, it is in your tone, not mine. You know perfectly well that there are most likely no readers of that journal here, and that few, if any members would have any idea what to make of luminance and chrominance even if they looked up the definitions. It is this that I find pretentious-- your need to make such statements-- to start discussions that you know few are equipped to engage you in, and that I disagree with. You wanna talk theory? Start another thread.

 

[domromer]

Ok so here is an apples to apples comparison. One pic is 3 raws, the other is made from one of the three raws. Both are straight out of photomatix no tweaking at all.

If I didn't do it I couldn't tell which is which.


By dsrphotography


By dsrphotography

 

[Arch]

max and helen you should just agree to disagree and leave it at that. In my experience i started using the digital HDR programmes fairly early on after their release so iv seen all the arguements that go with it. One of the most notable is the difference between the term HDR as its used now (for digital software) and the use of the words High Dynamic Range as they were used traditionally.
These two expressions get confused as you might have said to increase the dynamic range even by using tone mapping is giving the image a higher dynamic range.... were as nowadays its the cool trendy HDR programmes that are most associated with the term. So in a way i think you are both right.

domromer, if you are happy to use one file to produce an image with a higher dynamic range than you can achieve manually then fine, have fun with it.
But im affraid your tests dont mean anything, you can post similar looking shots all day long but the fact is a multi exposure HDR has MUCH more range than single exposure. If you like i can process two images properly and show you the difference, but its probably not even necessary.