Photoshop HDR Error: Not Enough Dynamic Range

[Boadicea]

I have been interested in HDR for a little while and wanted to give it a go. I use a Nikon D40x and took some contrasty raw shots of a boat on the beach. I then adjusted the exposure in Lightroom to give me six shots of ranging exposure from very light to very dark.

I then used Photoshop CS2 Merge to HDR but keep getting an error message that there is not enough dynamic range in these photo's to construct a useful HDR image. Could anyone venture a guess as to what I may be doing wrong. I have tried using both PSD and JPG images but it makes no difference.

Thanks

[Colin Southern]

I have been interested in HDR for a little while and wanted to give it a go. I use a Nikon D40x and took some contrasty raw shots of a boat on the beach. I then adjusted the exposure in Lightroom to give me six shots of ranging exposure from very light to very dark.

I then used Photoshop CS2 Merge to HDR but keep getting an error message that there is not enough dynamic range in these photo's to construct a useful HDR image. Could anyone venture a guess as to what I may be doing wrong. I have tried using both PSD and JPG images but it makes no difference.

Thanks

Hi Boadicea (interesting name!) - great to have you with us. Pop a reply onto the welcome thread when you get a chance and tell us a bit about yourself

With HDR you need to SHOOT a bracketed sequence of shots (at about 2-stop intervals) - you can't "adjust exposure in lightroom" because all that's doing is highlighting different parts of the normal range that you've captured. Also, HDR works best with images that haven't had any adjustments already made to them.

Hope this helps!

[Donart]

As noted above it's often reported that a series of bracketed shots are the starting point for an "HDR result". That said, it's also possible to get a reasonable 'HDR like shot' starting from a single image. (Maybe not for the purists, but what the hey.)
The path I take involves the creation of virtual copies in Lightroom then adjusting the exposures, exporting the resulting set of images to Photomatix for processing. You should have a similar experience and result using Photoshop.
Maybe you could check that you are exporting the images with the exposure adjustments made. For example in Lightroom you need to check the "Export with Lightroom Adjustments" box.

[Dave Humphries]

Hi Donart,

As I understand it, the "all from one image" route will really only bring any benefit if that one image is RAW capture, which has a minimum of 12 bits exposure to extract from. Starting from an 8 bit jpg as I believe Boadicea has tried doesn't really gain anything.

I could be wrong,

EDIT I was, not for the first time!

[Colin Southern]

@ Donart & Dave,

Re-processing a single source file can be easier than having to use extreme curves layers and the like (I sometimes do this myself), but - almost by definition - you can't get more dynamic range out of an image than was captured initially, and you won't be able to produce an image that you wouldn't have been able to produce from the single source file (although as mentioned above, the psudo HRD approach may well be easier).

You can certainly get something that has a "HDR look", but that's putting the cart before the horse; the usual idea is to make a HDR image look as normal as possible, not to make a normal capture look flat and washed out as is typical of many poorly processed HDR images; but if brighter highlights or darker shadows weren't captured in the single frame then no amount of "redevelopment" are going to make them magically appear for use in an HDR composite.

[Davey]

Hi Boadicea this might seem like a stupid question but there is quite an important reason behind it. When you say you're interested in HDR do you mean in capturing a higher than possible in one pic range. For example the boat at the beach you mention, with the boat and sky/water and all scene elements looking optimal brightness without being blown and having natural appearance, kind of how you remember or think it actually looked.

Or do you mean the strangely (some would say wrongly ) processed image where the tone mapping step remaps shades "incorrectly". The joke about wrong processing is kind of true, but not from the user input side (unless they were after realism ofcourse). If there is too high a range to display in one image then you have to remap the colours into a smaller range than can be displayed in a single pic. If you map them correctly the resulting tonally compressed image will look similar to the natural scene (although looking washed out and poor) and after some contrast and perhaps vibrance adjustments it looks like you've taken it in one capture. If you map the out of range tones "wrongly" and apply adjustments to accentuate this then the resulting scene looks very unusual and surreal. This has become popular and is sometimes refered to as the HDR look, when in actuality it's not really HDR but more to do with processing choices of such HDR images.

Either way whatever floats your boat (sorry, I couldn't resist that thinking of the OP example). It's just both those results are very different and take very different routes so advice is dependent on whatever of the 2 routes you choose. Particularly if the second look is the one you're after then in many cases you can work with a single image to get such a result without HDR techniques ever needing enter into it (thereby making less work and life easier). In scenes where there is a narrow enough range to capture in 1 shot taking more is pointless because there is nothing more to capture, likewise in a scene you can encompass whole range in 2 shots then why take 5 or 6.

[_GUI_]

Hehe, this must be one of the few forums where more people really know and understand what HDR is, than those who don't.

Boadicea, what Colin and Davey explained here is a far better intensive lesson about HDR than you will find in most places elsewhere.

You should have a clear idea of what the concept of HDR is, and afterwards decide if what you are really seeking is HDR _or_ the unreallistic (and IMO awful) appearance of the ultra-tonemapped images from all those proud Photomatix flickr users.

A short test: if the following image is not HDR for you, then I can tell you that you are not interested in HDR but in ultra-tonemapping effects.



BR

[atvinnys]

All,

I just had a question pop up in my head.
Most times, when folks are doing HDR, they take one raw, and create 2 copies with adjusted exposure (+2/-2)...
well, given what you mentioned Colin (you cannot create more dynamic range thatn what is actually captured), I am not sure what HDR would give them if they are using that method (instead of bracketing with the camera which for me makes more sense if you want to really increase the dynamic range).
I am sure that if I tried HDR it would make more sense to me as to what is still possible with one shot (instead of bracketing), but until I have the time to do so,....

I can certainly picture in my head the result with a bracketed series of shot (typical example is an object in front of a window : typical camera won't be able to show details in the darks w/o clipping the highlights..(something got to give on either side of the range). HDR for that is perfect (if I get the concept right, and I agree with GUI, I don't quite get why people like the extreme unrealistic look most HDR user are looking for...)

but none bracketed?...can't say I see what would happen....does anybody have example of that?

Cheers
Vincent

[Colin Southern]

but none bracketed?...can't say I see what would happen....does anybody have example of that?

I think what fools a lot of people into thinking that the "process 2 images from a single exposure" technique works is that often there is a far greater dynamic range captured with RAW then they realize (especially if the highlight end really pushed the sensor to the max) - problem is, a lot of it is buried down amongst the noise. If you're not used to digging out that kind of stuff with agressive curves and strong gamma adjustments then you probably just assume that it can't be done ... so ... when they see it done with 2 developements from a single RAW they think that it's some magic bullet - and thus the myth continues ...

... not realizing that if TRUE HDR is required then they won't have a hope in hades of getting away with it from a single exposure because all the info simply isn't in that single exposure to start with - plus (and I'm sure _GUI_ will back me on this one), even if you 1/2 success you'll end up re-defining digital noise in the dictionary (it'll say "refer to shadow areas in psudo-HDR images processed from a single capture!)

[Dave Humphries]

Colin,

You are of course right - well apart from that typo that needs an edit above HRD > HDR

It is very much horses for courses, some subjects cannot use bracketed exposures because of movement, so in this case, one shot RAW mangling is the only option to drag a bit bit DR into the final jpg.

I don't think anyone is suggesting that doing it with 3 or more, 2 stop separated images isn't the way it should be done.

Cheers,

[Colin Southern]

It is very much horses for courses, some subjects cannot use bracketed exposures because of movement, so in this case, one shot RAW mangling is the only option to drag a bit bit DR into the final jpg.

Gotcha back

I think that combining multiple interpretations (the inverse of the art form of multiplemisinterpretationalism! - always wanted to use that word) (along with antidisestablishmenterialism) of the same image - as a technique - is absolutely fine ... it's just not an HDR (or HRD!) image - probably "psudo HDR" is a better name for it.

Movement can certainly be a problem - but - usually theres a way around it (eg if you're producing a HDR composite from seperate images, and the movement is confined to their respective fames) - in other circumstances it's still possible, just takes a lot more work in PP.

* This post has been checed buy the arthor und is sertified two contane less then 100 errars!

[Davey]

I'd back colin all the way on the redefining noise point. HDR has strengths and weakness, one of the strengths is it lower image noise. Gui's raw merger is also worth looking at in this respect if it's feasable to take in 2 exposures then zeronoise wll have the advantage of producing natural single raw file without the noise compared to a scene that could be captured in 1 exposure (just) but needs pushing so much that noise becomes huge issue. His other stuff is worth looking at too for those interested in HDR because I've found it's more geared toward a natural result than other software and it's not inflexible because it avoids the one click process approach many programmes have so it basically does 1 thing rather than making a lot of choices for you. The down side of this is there is little automation (or upside depending on your outlook) but this means it's flexible and doesn't get in the way of your processing. Sure it's more work, but you have more control and that's what counts.

I personally think there is a much better way to work on a single raw where 2 or more captures is out of the question (but I'm no expert). By using local and selective editing you can do it. or instance ACR local exposure adjust masks etc, get it right as possible in ACR then after you've done as much as can step2 time. Open it in PS and start the next phase of dodge/burn/curves adjusting, vibrance/sat etc etc using masks to only apply where need to. Obviously this takes more time and fiddling than simply developing 2 images from one raw with a global change and combining and tonemapping but (and it's a big butt) the result will be far superior. I like to think of it as eating jar'd ready made sauce "done in 5minutes" compared to my own "2 hours to make" stuff, it's more messing but the end result is worth it. Of course taking time restraints and learning new stuff into account or large volume of work etc it's not always suited to travel down the best quality result, sometimes you need to sacrifice and compromise.

Obviously this is a longer route than most want but there is a difference between shortcuts and cutting corners. Cutting corners drops the quality, short cuts get you to the same destination quicker. Ie good shortcut is Photoshop actions for a standard process you perform can save a lot of time. I'm yet to delve into it but keep meaning to since it will take the drudgery out of some repetitive thinks I do for every image every time the same way. Actions have the same result as they have been manually tuned by you.

[Colin Southern]

It's good to see Davey reinforcing the point that I've made in the past as well - which in summery - is that HDR software only does the initial merging; after that there's just no escaping the need for "manual intervention" with dodging / burning / curves / gamma adjustments / selects etc ... and yet most seem to "forget" the requirement for this latter part.

If anyone is interested, I'd suggest getting "THe HDRI Handbook" by Christian Bloch for further reading; it's a bit technical, but pure gold

[_GUI_]

I think what fools a lot of people into thinking that the "process 2 images from a single exposure" technique works is that often there is a far greater dynamic range captured with RAW then they realize

I agree with this. Users should take more time to really study what a single RAW file is, and how much information it contains, and how to manually give shape to it, rather than looking for golden recipes (may times one-click processing software) that allow to do all that automatically.

[Boadicea]

Wow, thank you every body for your advice. I think I have learnt more about HDR in the last 5 minutes from reading all your replies than I ever expected to know. Thank you so much and I apologise for my tardy response. Computer problems!!!!

To provide answers to a couple of clarifying questions. I was using RAW images but as I am looking more for the type of HDR shot that GUI posted and am less interested in the comic book style HDR then I take on board the advice about the necessity of shooting additional shots to gather more information. The comic book style will no doubt find its place but I think the novelty will wear off.

As must be patently clear I have not previously attempted any HDR work and have only read a little of the background about the comic book style and figured that it must be possible to get a more dynamic but natural look using the same process. Obviously I was right in my thinking if not original.

There's a lot of info here that I don't understand but I will research more and no doubt ask more questions as I get stumped. I enjoy the PS side of things and spend hours happily playing with it so I am not so interested in the shortcuts as learning how to do it right ( prefer homemade red sauce).

Thank you all for taking the time to answer my question and provide the depth of information that you have.

[_GUI_]

If you are looking for a natural appearance, I recommend you to try Enfuse / TuFuse.
They work in a particular way a bit different to usual HDR programs. These programs work from several images at different exposures, and will produce an output image with the most appropiate exposure on each zone, without generating any intermediate HDR file.

The algorithm those programs use produces a fairly natural looking; rarely you find some dark halos but easy to correct.

I prefer to do manual tone mapping, but if I were to use some automated software this would be my preferred (and probably the only) tool. Particularly I prefer TuFuse, and used from the command line.

Source images:

Command line used:

C:\>tufuse -o salida_B0.5.tif 1.tif 2.tif 3.tif
C:\>tufuse -o salida_B0.6.tif -B 0.6 1.tif 2.tif 3.tif
C:\>tufuse -o salida_B0.7.tif -B 0.7 1.tif 2.tif 3.tif
C:\>tufuse -o salida_B0.8.tif -B 0.8 1.tif 2.tif 3.tif


Resulting images:

Picking the first one (has more info preserved) and adding a global contrast curve (arrow indicates halo dark artifact):

[Blazing fire]

and used from the command line.

Yet you're a GUI???

Btw, that's a nice shot and it looks so much like our eyes it's kinda freeky.

[Azz252]

I don't know much about HDR...but in regards to the "not enough dynamic range" issue i read elsewhere that if you strip the Exif data from the image you're working with Photoshop is fooled into thinking there is enough dynamic range and will let you work make the "HDR" image.

The reason being prior to stripping the exif it is the same for all three images hence why it thinks there is "not enough dynamic range". If someone already repeated this above..then you can ignore my lunchtime ramblings

[Davey]

It might fool photoshop into thinking it is 3 different images but the problem remains that there is still the same dynamic range so it's a bit pointless because you don't gain anything and just get all the drawbacks. A manual local exposure adjustment etc will yield much better results without any of the drawbacks of HDR (which is only recommended in merging captures of higher than possible in 1 capture).

[Dave Humphries]

It might fool photoshop into thinking it is 3 different images but the problem remains that there is still the same dynamic range so it's a bit pointless because you don't gain anything and just get all the drawbacks. A manual local exposure adjustment etc will yield much better results without any of the drawbacks of HDR (which is only recommended in merging captures of higher than possible in 1 capture).

Hi Davey,

People keep saying this, but I'm still not sure I agree under certain circumstances, consider this:

If the source image is a properly exposed 12 bit RAW, that has 12 bits of dynamic range, which I make to be 4 stops more than can be displayed in an 8 bit jpg.

If one converts it in to three jpg (or 8 bit Tiff) files, simplistically, one might say;
one at nominal exposure, that uses bits 3, 4, 5, ... 9 and 10, plus
one at 2 stops over, that uses bits 1-8, and
one at 2 stops under, that uses bits 4 - 12.
(I may have these last two the wrong way round, but you get the idea)

In this case I can see merit in azz252's tip for the jpg EXIF.

Those 3 files MUST have sufficient dynamic range for HDR to do its stuff and then tone map back into a typically flat looking 8 bit output file.

I am quite willing to be told I have the wrong end of the stick here, either about RAW conversion and bit mapping, or how HDR works.

AN AFTER THOUGHT: maybe I am not considering the full potential of ACR, my version with PSE6 doesn't have the curves tab, so maybe that's how you would achieve what you are talking about without recourse to HDR.

Am I mad?