Creating natural-looking High Dynamic Range images

[Sandeep]

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!   

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.



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1) Exposure bracket (-2 ev)





2) Exposure bracket (0 ev)





3) Exposure bracket (+2 ev)











......and the FINAL image:






......plus the Second alternative...



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! 

[theqca]

This is good stuff Sandeep... Look forward to reading the entire end to end workflow

[LightWave]

Lol. That's such a teaser. Looking forward to the full steps.

[WILD CAT]

I like your landscape shots so I'm also looking forward to read the entire tutorial

[Jasii]

Awaiting for the goodies to flow in!

[gautam023]

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.

[Sandeep]

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.

[Hot Shoe]

Thanks for this initiative Sandeep. Looking forward to a detailed tutorial.

[Sandeep]

Added a second alternative..will take up whichever you guys like better..

[PixelHunter]

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.

[VikramF]

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.

[Sandeep]

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.

[Sandeep]

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





Histogram & shooting parameters for (0 ev) bracket






Histogram & shooting parameters for (+2 ev) bracket





Histogram for FINAL image #1





Histogram for FINAL image #2




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

[Sandeep]

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    


(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:


(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).




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? 

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

[LightWave]

Very good so far. Should be pretty useful for people trying to understand histogram. Waiting for more. It's Saturday today