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Learn Photography & Knowledge base => Tips, Tutorials & Interviews => Topic started by: Sandeep on December 21, 2014, 11:11:35 PM

Title: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 21, 2014, 11:11:35 PM
Hey Guys,

I am working on a tutorial on how to create natural-looking High Dynamic Range images with MINIMAL noise. What I will be walking through is my bread & butter workflow which I follow on 90% of my landscape shots. So if you hate my landscape images, stop right here!    :P

Also, what is "natural" looking would be a topic of endless debate. So when I say natural here, it means what I find and accept to be natural to my eyes and brain.


My initial plan was to put in the first part of the tutorial today, but as of now I have only managed to capture screenshots of the entire process - about 40 screenshots & images. This being my first tutorial ever, I definitely underestimated the time it would require.

Now I will be posting the first part next weekend. But meanwhile I want to show you the original SOOC exposure-bracketed jpegs and the final image that will be createad using them.




-------------------------------------------------------------------------

1) Exposure bracket (-2 ev)
(https://farm9.staticflickr.com/8615/15451918233_57319ea998_o.jpg)




2) Exposure bracket (0 ev)
(https://farm8.staticflickr.com/7503/15449281784_b062e3e3b2_o.jpg)




3) Exposure bracket (+2 ev)
(https://farm8.staticflickr.com/7524/16045778426_2f4e388570_o.jpg)










......and the FINAL image:

(https://farm8.staticflickr.com/7482/15885423709_76417f4590_o.jpg)




......plus the Second alternative...
(https://farm9.staticflickr.com/8646/15897248100_123b98e110_o.jpg)


I will be going through each and every post-processing settings step-by-step, using histogram all way along. So if you are someone who does not know (or are scared) to utilize histogram, this tutorial should hopefully be a good primer for you.


(EDIT: Now that I see the final image again, the fog along the mountain ranges seem a bit over-the-top. But that is something you can easily tone down if you want to. I'll touch on that part too next weekend) .



Till then cheers & have a good week ahead!  :)
Title: Re: Creating natural-looking High Dynamic Range images
Post by: theqca on December 21, 2014, 11:23:13 PM
This is good stuff Sandeep... Look forward to reading the entire end to end workflow
Title: Re: Creating natural-looking High Dynamic Range images
Post by: LightWave on December 22, 2014, 05:05:49 AM
Lol. That's such a teaser. Looking forward to the full steps.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: WILD CAT on December 22, 2014, 09:25:11 AM
I like your landscape shots so I'm also looking forward to read the entire tutorial :D
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Jasii on December 22, 2014, 10:38:34 AM
Awaiting for the goodies to flow in!
Title: Re: Creating natural-looking High Dynamic Range images
Post by: gautam023 on December 22, 2014, 12:48:04 PM
Sandeep, please go on. I have always liked the subtle tones in your processing [not present in the attached picture though. You got a bit overboard for your taste].
Thanks for submitting.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 22, 2014, 01:21:50 PM
Cool!

Gautam, thanks for the frank input. Yes it is an over the top output. I overdid every setting by a tiny notch to show the difference it made to the image compared to a step before. 
That said,  allow me to rework on it over the week to create a more pleasant image.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Hot Shoe on December 22, 2014, 03:54:46 PM
Thanks for this initiative Sandeep. Looking forward to a detailed tutorial.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 23, 2014, 09:06:23 AM
Added a second alternative..will take up whichever you guys like better..
Title: Re: Creating natural-looking High Dynamic Range images
Post by: PixelHunter on December 23, 2014, 11:54:25 AM
Thanks for this initiative buddy. I always seem to have trouble in creating HDR images. As a result, though I have lots of bracketed images, never actually managed to create one. Waiting for your tutorial.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: VikramF on December 23, 2014, 01:11:42 PM
I think the first version is a little better as it's got more contrast. The 2nd attempt has it's curves all pushed towards the middle - not too much contrast at all.

Will wait for your tutorial before commenting on the method you've used to produce these ... a great initiative.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 23, 2014, 04:38:07 PM
Binoy - I would be very happy if you find my tutorial useful to bring your brackets back to life :-)

Vikram - The second does have less local contrast..it is actually built on top of the first but without one plugin step in between.
It'll be really great to have  your feedback on my process.. I'm sure we'll all learn a lot from your insights.


Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 24, 2014, 09:35:50 AM

Posting the three brackets and the two final images with their respective shooting parameters & histograms. For those who don't know how the histogram works, as of now just take a look at the VISUAL differences between the brackets and also the final images. I will try and explain how to read and (importantly) utilize them while post processing when I start with the tutorial.



Histogram & shooting parameters for (-2 ev) bracket
(https://farm8.staticflickr.com/7504/16070088652_bd4f07825e_c.jpg)




Histogram & shooting parameters for (0 ev) bracket
(https://farm8.staticflickr.com/7501/15884698339_4f6138ba0b_c.jpg)





Histogram & shooting parameters for (+2 ev) bracket
(https://farm8.staticflickr.com/7501/16070787255_cdcf51684e_c.jpg)




Histogram for FINAL image #1
(https://farm8.staticflickr.com/7571/16091503062_1cf91eda43_c.jpg)




Histogram for FINAL image #2
(https://farm8.staticflickr.com/7543/15904781918_0ef9a57c1b_c.jpg)



I intend to make this a collaborative tutorial, where you guys can post your questions, comments, feedback, and improvement to my workflow at any point of time. This way, by the time we finish the tutorial, everyone (including me) would have learned something useful that can be applied to our future image processing.



Thanks!
Sandeep
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 25, 2014, 10:53:37 PM
Part 1: Getting the Basics Right

-- Introduction

HDR, or High Dynamic Range photography, has been a subject of criticism by "purists" from the time it was discovered. They look at it with contempt and you will often find them ridiculing it on any photography discussion forums. But while doing this, they conveniently forget the fact that HDR is just a technique, a tool, which does not create anything by its own. The output depends on what it's fed , and how it is used. Like they say in software industry: Garbage-in, Garbage-out.

Their contempt might have to do with thousands of funny, and often nauseating, images created by people using HRSoft's Photomatix Pro software. The internet was littered by crappy HDR images in the beginning years of HDR "discovery". Over time, people have (thankfully) learned to be a bit subtle while using Photomatix though, and also the software has gotten a lot better. However, now the bone of contention usually among the purists is that the images, though attractive, do not look "natural". I myself don't care about the natural-ness of an image as long as it looks pleasing and evokes emotions while watching it. For me, the real issue was that the "Tone-Mapping" process of creating HDR images in Photomatix did not give good results most of the times, and I was forced to make sure that I shoot only those scenes and elements, which Photomatix might render nicely. That was too much of a restriction, and I started looking around to find ways to increase my hit-ratio of HDR images. The process which I am describing in this tutorial, is a combination of knowledge I gathered over the internet in past 2-3 years, and of my own personal experience (good as well as bad) while processing a few hundreds of HDR images till now.



Now before we begin, I hope everyone here would at least have a basic idea of what HDR means.

HDR, IMO, is a very broad terminology. It basically means we are trying to capture & reproduce a very high-contrast scene which our camera sensors cannot capture faithfully in a single exposure. You also need to understand that even this is a very loose definition for HDR. It's meaning/interpretation will keep changing as digital photography keeps evolving, and we see sensors with higher DR capabilities almost every new year. Except in case of Canon, of course.
Sorry!... couldn't control myself  :)



Anyways, let's leave it at that and proceed further.



-- Lets Begin!

As you would've seen in my very first post in this thread, there are three source JPEG files to work with here, and two outputs which we will work towards.
The source JPEG files are of -2ev, 0ev & +2ev.

You can capture these exposure brackets in anyway you feel comfortable.I personally like to use Aperture Priority in AEB mode with self-timer. Another option would be to use Manual mode to set your "normal" 0ev exposure(like you'd do for any normal single exposure), and then fire the shutter in AEB mode using self-timer. (Please read your camera manual to know how to shoot in AEB mode). Whichever mode you use, the most important bit is to get the histograms of your brackets right.

For 0ev: Your graph should be distributed over the ENTIRE X-axis of the histogram, and also hugging the left and rightmost walls. Unfortunately this particular 0ev exposure is not a right example of this. Please give me benefit of doubt here and assume that the graph is hugging both the left and right side -- its my first tutorial :)   
(https://farm8.staticflickr.com/7545/16045783116_3d05411e63_c.jpg)

(Don't worry about the the Y-axis)

(In a Histogram the leftmost wall is a marker for absolute black ,whereas the rightmost wall is the marker for absolute white. So if the histogram of your photograph shows some part of the graph hugging the left wall, then it is telling, or rather screaming, that your image has some parts whose details are LOST IN SHADOWS. And similarly, if there is a part of graph hugging the rightmost wall, it means your image has areas whose details are LOST IN HIGHLIGHTS.

If you see this then it means the scene you are trying to capture/or already captured has such a large range of dark and bright areas that it is over and above the DR capability of your camera sensor. And it also means that it is time to switch to HDR)


For -2ev: Your histogram should be anything BUT hugging the rightmost wall. The idea/aim here should be to underexpose to a level that you donot have any details lost in highlights (i.e no part of the graph hugging right wall of histogram) Like below:
(https://farm8.staticflickr.com/7576/16070880072_6a44495de0_c.jpg)

(Now there would be times when a -2ev exposure would not be enough to get your graph off that rightmost wall. This is when you will have to take additional under-exposed bracket, say for example a -4ev. However these would be  rare situations if you shoot mainly in the golden/blue hours, and for sake of simplicity I will stick this tutorial only to brackets of -2, 0 & 2ev)


For +2ev: Your histogram should be anything BUT hugging the LEFTMOST wall. As you should have guessed by now, the aim here will be to OVER-expose to a level that there are no details lost in shadows  (no part of the graph hugging the left wall).
(https://farm9.staticflickr.com/8682/15884150728_38ec43613b_c.jpg)



From my experience, I have found that above histogram guidelines for brackets will give me a better HDR file to work with - one with equal amounts of details in dark, mid and bright portions. Else I would end up with a HDR file with more shadow details but less highlight details, or vice-versa. That's not desirable. So, as much as possible, try and stick to the above guidelines while capturing your brackets while shooting itself. Hope you do know that your camera LCD has a feature to show histogram of the captured exposure?  :D

For any reason if you did not get the histograms right while shooting, fret not! Especially if you shoot in RAW (or even jpeg in case of a Fuji  ;) ), you will have enough latitude to tweak the exposure of your brackets later to get the desired histograms.
Consider the JPEGS in this example. They were shot in AEB of -1, 0, +1 jpeg brackets, as Fuji XE-1 only allows a maximum of +/-1 ev differential brackets in AEB mode. But before beginning the HDR processing I underexposed the -1ev bracket by further 1 stop, and overexposed the +1ev bracket with an additional 1 stop in Adobe LightRoom to bring to the desired starting point.

That's all the basics you need to know before heading further.

I know this part was a bit too basic & theoretical. But I wanted to clarify the usage of histogram to the uninitiated, and also explain the above important guidelines for optimally prepping your jpeg/raw brackets before starting with the most important step in this tutorial - Generating the HDR file.

See you all on Saturday then..
Do share your feedback, comments & corrections(if any) to this part.

Thanks!
-Sandeep


Title: Re: Creating natural-looking High Dynamic Range images
Post by: LightWave on December 27, 2014, 05:01:29 PM
Very good so far. Should be pretty useful for people trying to understand histogram. Waiting for more. It's Saturday today
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 27, 2014, 09:50:11 PM
Down with a bloody painful bodyache doc..Will have to continue tmrw..If crocin does the trick tonight.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: DrShama on December 27, 2014, 11:20:41 PM
This is going to be a very informative and useful tutorial for beginners like me as I don't know much about HDR photography. Look forward to reading part 2. Get well soon Sandeep.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: kaushik_s on December 28, 2014, 02:47:51 PM
Good going Sandeep :) Now waiting for the rest, once you get better ofcourse.

PS: BTW, the first final image have a green band on upper left corner and purplish band on the mountain range on middle right. You've corrected that in your 2nd final image and so you might like to elaborate on what happened there too. That would be helpful I guess.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 31, 2014, 09:57:45 AM
Sorry guys, I couldn't write the next part last weekend. Having some or the other health niggles since a week now. Right now recovering from a bad throat infection  :-\

Planning to post the next important part of "Generating HDR file" tomorrow.

Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on December 31, 2014, 10:00:35 AM
PS: BTW, the first final image have a green band on upper left corner and purplish band on the mountain range on middle right. You've corrected that in your 2nd final image and so you might like to elaborate on what happened there too. That would be helpful I guess.

Yes - let's just say that the 1st final image is a good example of a subtle over-processing  :)..and that will get covered.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Bharat Varma on December 31, 2014, 04:17:37 PM
But where are your landscape shots?
How can  I decide whether to "stop right here" or not if I haven't seen your landscape shots? :)

Laudable effort. Looking forward to more details.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on January 01, 2015, 06:21:32 PM

PART 2: GENERATING THE 32-BIT HDR FILE

In this part we will create a 32-bit “HDR” TIFF file from the 3 input bracketed JPEG files. Having a 32-bit TIFF file essentially means we will have the COMBINED Dynamic Range goodness of ALL the 3 input JPEGs in ONE SINGLE file. This will give us the ability to edit a HDR file like we edit any other single-exposure file without needing to use the “Tone-Mapping” process of any HDR software. Thus, highly reducing the probability of generating an “artificial” looking image, or creating a halo-filled disaster.

Been there, done that  :P


The software’s used here are:

1-   Adobe Lightroom – Main processing application. Required (version 4.0 +).
2-   HDRsoft ‘Merge to 32-bit Plugin for Lightroom’ – The Magic Bullet. Required.
(http://www.hdrsoft.com/download/merge_lrplugin.html (http://www.hdrsoft.com/download/merge_lrplugin.html))
3-   Topaz Adjust 5 plug-in for Lightroom – Additional effects plug-in. Optional.




The Process:

The HDRsoft Merge to 32-bit Plugin for Lightroom is available in Lightroom as an “Export” option.
So once you have the bracketed JPEGs ready (preferably as we discussed in the previous part), the next step will be to export them to the plug-in as shown below:

(Select them all > Right-Click > Export > Merge to 32-bit HDR)


(https://farm8.staticflickr.com/7497/16071577975_b2340cf89c_c.jpg)




A pop-up will come giving various options for exporting the 3 brackets to 32-bit HDR TIFF file.

(https://farm8.staticflickr.com/7475/15449279564_0dda1d67ca_z.jpg)
(Hover over each option to read what the particular setting is meant to do)



I will always check the "Align Images" and "Crop aligned result" options.
Under them the first option “by correcting vertical and horizontal shifts” is ideally for tripod taken brackets, while the second is for hand-held brackets. I almost always use the second option, as I never remember which pictures were taken with tripod and which were hand-held after the shoot.

I never choose the “Remove ghosts” option. One, because the software maker itself says that it reduces the quality of the merged file, and second, since I usually shoot landscapes with clouds and/or some water bodies in it, I prefer if the merged file has a sum total of the cloud/water movement from all three brackets. It gives a more dreamy look. And also with all those thousand tree leaves swaying their own merry self during the relative long exposures selected at dawn/dusk, I highly doubt how much this option would help.

As for “Reduce Noise”, I would normally select the “Underexposed image(s) only”, since I prefer a longer exposure time compared to bumping up the ISO while shooting - so just doing NR on the underexposed bracket should suffice. Here however I was trying out a feature in Fuji XE1, which only works at ISO 800.  Hence I went with “All source images”.
(Note: It’s up to you if you want to do NR at the beginning of the process or at the end in Lightroom. Ideally you should do multiple trial and errors to see what works best for your camera sensor output and processing style.)


The next section is about how you want to save the file. I prefer the settings shown in the above screenshot. You can hover over each option to see what settings you would prefer instead.

(Note: The plug-in will remember your settings from the previous merge)


Once satisfied with everything, click on Merge.


Lightroom will now export the input brackets to the HDR plug-in, which will apply the pre-processing settings you chose in the pop-up window, and will eventually merge them into a SINGLE 32-bit TIFF file.

(https://farm9.staticflickr.com/8593/15885492739_b7b86e9db4_c.jpg)



When all is done, you will return back to Lightroom. Now locate the merged TIFF file based on the name you gave, or just un-stack it from one of the  brackets if you chose this setting in the saving options.


The 32-bit image will look something like below:

(https://farm8.staticflickr.com/7527/16045780346_0a3341194b_c.jpg)



Not very pretty, yes ?  :)



If you have used any HDR software earlier, you will know the reason why.

For those new to HDR, this is just an intermediate HDR file, which has a lot more information than your monitor has the capability to display. It needs to be “Tone-Mapped” (or dumbed-down), so that it will look good on your display monitor. Usually this tone-mapping is done in the HDR software which creates the HDR file, but they do not have a 100% hit-ratio of producing pleasing results (at least for me). The only difference in our case here is that the HDR file will be tone-mapped using Lightroom (from version 4 onwards Adobe added this functionality into LR), instead of using the tone-mapping algorithms of other HDR softwares.



This "tone-mapping" in Lightroom will be no different from how you process your normal single-exposure photographs. Process will be same just that your file will now have a large dynamic range, and also larger tolerance for processing before the over-processing artifacts and noise starts creeping in. Do note that it is easy to get overboard thinking that now we have a hulk of a high-DR file, and over-process it so much that it eventually breaks down and starts showing artifacts..like how I managed to do in my first final image..as kindly pointed out by Kaushik in his reply above  :)

----

Now, ideally speaking, this is the point at which my tutorial “Creating natural-looking HDR images” should end, since we have created a 32-bit High-DR file which can be processed as naturally as any other single-exposure can be – depending upon your individual processing approach and choices.


However, I want to extend this tutorial by also explaining how I approached each setting in the Lightroom ‘Develop’ module and what was my thought process and logic behind various settings for exposure, blacks, whites, saturation,hue, sharpening, noise-reduction etc. in producing the below two final images.
1.
(https://farm8.staticflickr.com/7571/16091503062_1cf91eda43_c.jpg)

2.
(https://farm8.staticflickr.com/7543/15904781918_0ef9a57c1b_c.jpg)



My idea here is to help beginners who might currently be intimidated by the term “post-processing”, perplexed by seeing multiple sliders, and importantly are unsure of how to decide when to move which slider, and by how much. Because that's exactly what my situation was 3 years back  :)

There are many people on this forum who have far better processing knowledge and artistic approach than me. So it will be very nice if they can also help along by giving their feedback to my processing workflow, correcting me wherever I may be going wrong, and suggesting an alternate way to do things right.


That's all for now.

Hope it was helpful to some. Beginners! Don't worry if you did not understand everything I wrote! Suggest you to read it once more, and then do these steps with any bracketed shots you have. Or else you can use the 5mp downsized, 100% jpeg quality of the original brackets to create your own HDR file. So that when I begin explaining my processing steps on the HDR file to create the final tone-mapped versions, you can also play along..


See you next week! 

Thanks!


Sandeep
Title: Re: Creating natural-looking High Dynamic Range images
Post by: LightWave on January 02, 2015, 02:16:04 AM
Good going. Haven't used that HDR soft plugin before. Only tried HDR merge in PS and didn'tlike it too much. Shall give this a try.
Title: Re: Creating natural-looking High Dynamic Range images
Post by: Sandeep on January 02, 2015, 08:13:34 AM
Yeah the PS HDR thing has an even worse hit ratio! Tried that once or twice when Photomatix Pro didn't gave the desired output.