Tag Archives: Definition of High Dynamic Range Imagery

Why Dynamic Range is NOT Tonal Range

Why Dynamic Range is NOT Tonal Range

Now, it could be…but it’s not

It’s like a square is a rectangle but a rectangle is not a square…so let’s explore this

I recently was reading an article explaining dynamic range, in it, the author went on to explain when a camera has a limited dynamic range it will only show shades of gray not black and white. And I thought, no, that’s limited tonal range, not dynamic range.

Most everything we use in photography has a Full Tonal Range when lit with the same constant light source

  • Our Eyes; can see the full tonal range from Black to White
  • A High End Camera; can reproduce the full tonal range from Black to White
  • A Low End Consumer Camera; can reproduce the full tonal range from Black to White
  • Most decent LCD Monitors: Can produce a full range of tones from Black to White
  • Most Better Photo Printers: Can produce a NEAR full range of tones from black to white (Limited by Paper white {DMin} and Black Ink (DMax} )

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The Definition of HDR

The Definition of HDR 

So I was reading on a forum the other day about the definition of HDR, High Dynamic Range Photography. Some people argued there wasn’t one, most other argued to make what ever they shot- the definition of HDR and a lot of truly baseless arguments and more of rationalizations.  I put a few of my thoughts in but it really went no where and I didn’t feel like arguing anymore. 

So I thought I would give MY definition of what HDR is. This, like everything else on my blog, is my opinion. And my opinions are based on my experience or what I have done only. I’m not schooled nor have a degree in anything I have ever done in photography. I speak only from what I have done, experienced, experimented with. Am I right? I don’t know. I only know what I think I know. But I won’t tell you what “they” say. I will tell you what I know. 

Looking at the definitions people had for HDR: If it was beyond the dynamic range of a Monitor, It was HDR. If it was processed with HDR software, it was HDR. If it was tone-mapped it was HDR. If it was a RAW image, it was HDR. If it was 3 Exposures from a single RAW image, it was HDR. 

All of which I would just say…No. 

It seemed most people just wanted to justify that their single exposure or whatever they shot, however they shot was HDR because it looked HDR. Which I will again say…No 

So here is my definition of HDR. 

There are many things that have a dynamic range. A print (100:1) a Monitor (100:1 – 1000:1) A camera single image (1:1000 – 4:000:1) NONE of those are High Dynamic Range and just because you may exceed one of those examples of Dynamic range  does not make an image an HDR. Every one of those are Low Dynamic Range. 

My definition of High Dynamic Range Images is based on SCENE DYNAMICS. Scene dynamics that I believe are High Dynamic Range are those that are above what a Camera can caoture in and a single image and are 10:000: 1 or “As the eye sees” or higher such as the 100,000:1 that are very possible in nature (Remember those images with the sun in them?) 

If you use High Dynamic Range techniques but capture a low dynamic range scene is it truly High Dynamic Range Imagery? No, I don’t think it is. And yes I have done such things and posted them here and I also showed cases where that scenario goes horribly wrong. I still believe if you can capture the image in one exposure, then you don’t need nor would I advise you to use HDR techniques. 

Does that mean I am against single image processing or tone mapping? No, I have softened my stance on that. It actually can be quite fun and I did have some fun using Topaz Adjust 4 & 5. BUT I firmly do not believe they are HDRs. They are what they are – fun. 

And if you remember this post, I do believe there actually is a reason to use tone-mapping on single images. But that is NOT to make an HDR, but rather to map tones more closely to how the human eye sees. I believe that the basis for how a digital sensor “Sees” was based on a film model; and not on the human eye.( Alowing that they do account for the eyes sensitivity to colors) It was based on something linear and I don’t believe the human eye is that linear. Just as human hearing is not linear (we are more sensitive to high frequencies than we are to low, well until we get old). So I am fine with people tone-mapping single images. They just aren’t HDRs. 

So if you capture what is not capturable with a single image and that range is closer to what is visible by the human eye or higher, I believe you have captured a true High Dynamic Range Image, which of course we have to tone map down to a Standard Dynamic Range Image to be displayed on monitors or in print. 

My 2 Cents on the matter