An Introduction to High Dynamic Range Imaging (HDR)

An Introduction to High Dynamic Range Imaging (HDR)


Today I’m pleased to present an introduction to High Dynamic Range Imaging (or HDR PHotography) that has kindly been written by Jason Bouwmeester. 

An Introduction to High Dynamic Range Imaging (HDR)

HDR, or High Dynamic Range Imaging seems to be all the rage these days. HDRI is described as:

In image processing, computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures (the range of values between light and dark areas) than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows. (from Wikipedia)

More accurately however, the images that are commonly seen and referred to as HDR or HDRI images are tone-mapped.

Tone mapping is a technique used in image processing and computer graphics to map a set of colours to another; often to approximate the appearance of high dynamic range images in media with a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a limited dynamic range which is inadequate to reproduce the full range of light intensities present in natural scenes. Essentially, tone mapping addresses the problem of strong contrast reduction from the scene values (radiance) to the displayable range while preserving the image details and color appearance important to appreciate the original scene content. (from Wikipedia)

Definitions and technicalities aside, I decided to look into HDR and tone mapping a bit closer to see if there really was a difference between different processes. I was curious to see if there was noticeable differences between generating HDR/tone-mapped shots from a single RAW, multiple RAWs, multiple JPGs from the camera, and multiple JPGs generated from a single RAW. For the purposes of the rest of this post, I will be referring to my final images as HDR images (even though we all now know that’s not exactly correct). Here is the original, straight out of the camera image shot with my Canon Digital Rebel XT/350D.


SOOC (straight out of camera) shot

Honestly, not a bad image for SOOC! Anyways, the recommended way to produce HDR is to take multiple exposures using your camera’s Auto Exposure Bracketting (AEB) setting. I’m not going to get into the details on this, I’m merely posting my comparison results here.


In the past, I’ve used the ReDynaMix Photoshop plugin to generate my HDR images from a single RAW file. It really can’t be beat for the $16 price tag. It worked pretty decently, but I’d heard that Photomatix was a much better program to use. Below is the image above run through the ReDynaMix plugin.


ReDynaMix HDR

Not too shabby.


Photomatix is a much more robust, and more expensive ($99), program to use but allows for blending of multiple exposures into a single HDR file, as is recommended. I’m going to be up front here. I don’t walk around with my tripod in my back pocket, so taking multiple exposures without getting movement is very difficult. I tried Photomatix ages ago, but for some reason I guess I just wasn’t steady enough. Fortunately, this set of multiple exposures turned out and aligned nicely when I imported them into Photomatix. The three shots were taken at an exposure value of 2, meaning I had a shot that was properly exposed, one that was underexposed by 2 steps and one that was overexposed by 2 steps. Because the Canon Digital Rebel series only allows for 3 photos in AEB mode, that is all I am going to use. Using the .CR2 (RAW) files out of the camera I created the HDR image you see below (note, clicking this image takes you to the Flickr page). I processed it as I normally would process for HDR, tracked the settings and made some final curves and unsharpen mask adjustments in Photoshop.

Photomatix 3 exposure HDR from RAW riles

Photomatix 3 exposure HDR from RAW riles

It’s pretty close to the ReDynaMix version, but definitely crisper and more variation between the dark and light areas. This is especially noticeable in the BMW logo area, below the BMW logo on the grill, the upper right corner, the dirt/water streaks and between the buildings near the top. A much better looking HDR image in my opinion. As a comparison, I created an HDR image using the corresponding JPG files from the camera. I used the exact same Photomatix settings and Photoshop Curves and Unsharpen Mask adjustments. The image below is the result.

Photomatix 3 exposure HDR from in camera JPGs

Photomatix 3 exposure HDR from in camera JPGs

Still crisper than the ReDynaMix version, slightly washed out I think from the RAW version, but not much.

Camera JPG or generated JPG?

If you’re still reading, thanks for sticking with me this far. This is what I was really wanting to test out. Are there noticeable results between exposures generated in camera, and exposures generated using Photoshop’s Camera RAW plugin from a single RAW? Using the Camera RAW plugin for CS3, I can generate JPG files with various exposure values ranging from -4 to +4. For the intent of this test, I created a -2EV and +2EV from the 0EV RAW file out of the camera, and used the 0EV JPG from the camera as well. Below are comparison shots of the in camera EV JPG files (on the left) and the Photoshop generated EV JPG files (on the right). The top image is +2EV, the bottom -2EV.

In camera JPG versus Photoshop JPG +2 exposure

In camera JPG versus Photoshop JPG +2 exposure

In camera JPG versus Photoshop JPG -2 exposure

In camera JPG versus Photoshop JPG -2 exposure

As you may be able to see, the Photoshop generated JPG files are a bit lighter and washed out, but only slightly. Using the two newly generated EV JPG files and the originally exposed JPG from the camera, I recreated the HDR image, again using the same settings as before. The images below are a comparison between the in camera JPG HDR file (top) and the Photoshop generated JPG HDR file (bottom).


Photomatix 3 exposure HDR from in camera JPGs

Photomatix 3 exposure HDR from Photoshop JPG

Photomatix 3 exposure HDR from Photoshop JPGs

Can you see the difference? Sometimes I think I can, then other times I think I can’t… there are some areas that are a little lighter and perhaps washed out, for example the area below the BMW symbol, but all in all, it isn’t much.

The final test: 3xp or 7xp?

And that concluded my test. Or so I thought. I see people producing HDR images with 3, 5, 7 and even 9 exposures set to various EVs from 1/3, 1/5, 1 and 2. So I thought I’d do a quick comparison between an HDR using the 3 Photoshop generated exposures and 7 Photoshop generated exposures with an exposure value of one. In layman’s terms, the bottom image above uses +2, 0 and -2 EV JPG files, the image below uses +3, +2, +1, 0, -1, -2, and -3 EV JPG files.

Photomatix 7 exposure HDR from Photoshop JPGs

Photomatix 7 exposure HDR from Photoshop JPGs

Some obvious differences between the two images, there’s a bit more range in the 7 exposure version, which is understandable.

The verdict

Thanks for hanging in there, hopefully I saved you some time with having to go through this process yourself. The image below (clicking will take you to the Flickr page, which you may have found this article on) is the 4 final HDR versions in a mosaic for easier comparison. Top left: 3 exposure, 2 exposure value, in camera RAW; top right: 3 exposure, 2 exposure value, in camera JPG; bottom left: 3 exposure, 2 exposure value, generated JPG; bottom right: 7 exposure, 1 exposure value, generated JPG:

Final comparison between RAW, JPG, 3 exposure & 7 exposure HDR

Final comparison between RAW, JPG, 3 exposure & 7 exposure HDR

Seeing the images together like this, you can see subtle differences between the three 3 exposure shots (top left, top right and bottom left), and you can see a bit more color variation in the bottom right 7 exposure shot. I do think that the HDR generated from the camera .CR2 (RAW) files turned out the best, I wish my camera was capable of doing 5 or 7EV shots without having to change the settings, and I also wish I was a human tripod. That being said, neither is going to happen and if I showed you each of these images separately, unless you are an HDR geek/expert/guru, you’d be hard pressed to see the differences or tell me one looked better than the other. That being said, I’ll most likely use the Photoshop generated JPG files for my HDR’s unless I have a tripod or can be certain I won’t budge between exposures. Besides, I’d never get an HDR like this based on 3, 5, 7 or 9 EV exposures in a camera: Thanks for stopping by, and I hope you found this informational and useful! Happy HDR’ing. 28752-BMW-HDR-600

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Darren Rowse is the editor and founder of Digital Photography School and SnapnDeals. He lives in Melbourne Australia and is also the editor of the ProBlogger Blog Tips. Follow him on Instagram, on Twitter at @digitalPS or on Google+.

Some Older Comments

  • Jason May 21, 2011 11:07 am

    All the flickr photos are missing... any chance you could rehost them so that your examples and explanations have more impact?

  • Sanjay February 12, 2011 12:09 am

    I read a lot of post about HDR but this better than all.


  • xxx December 4, 2010 06:33 am

    I do agreee on that topic. xxx

  • Nav June 3, 2010 08:13 pm

    Thank you very much for a detailed information about HDR. I ve been trying to generate HDR with both Photometrix and Photoshop CS4 ( merge to HDR feature). I get terrible looking results. I am using 3 AEB shots.. :(
    Will give it a shot again :(

  • Eric Corrus November 28, 2009 09:19 am

    Very good tutorial. I've been using most of the same techniques already but it's nice to know I'm doing things the right way. Well, the accepted way at least. I use Photomatix as well and leaned about the fake-HDR from a single RAW from your write-up. I tried it and it works! Compared to the 3-shot image I did, the results weren't as good, but certainly something the untrained eye would notice. Thanks for the little time-saver.

  • Angus Leigh October 19, 2009 01:00 am

    HDR is the technique that exactly handles the following situation that trouble me at Extreme Lighting Photography

  • Landscape Photography July 18, 2009 12:30 pm

    3 exposure in camera raw files looks best. Unless one was actually capturing the multiple exposures in the camera and thus capturing a wide amount of detail wouldn't it be easiest just to use a layer mask to control exposure locally within one image.

  • Lee July 19, 2008 03:43 am

    I posted a semi-review of Dynamic-Photo HDR on my blog today. In my experimenting, I found that working with three bracketed RAW files produced the best results. But, for photos where I didn't take bracketed shots, producing TIFF files from the RAW original at different EV settings was a close second in results. With TIFF files you don't have to deal with compression issues like you do with JPG. Finally, where I only had a JPG image to work with, I still got decent results. You can see some of my trial results on my blog.

  • Gus July 4, 2008 03:30 am

    I used to see thess HDR photos on flickr before and I remember I was absolutely stunned. I had no clue how they created them but now I've learned a bit and I find it very interesting and I believe you can create some great looking pieces of art with HDR.

    Take a look at my first HDR photos:

  • Jason June 26, 2008 03:08 am

    Paul: pity indeed... I don't have a Mac but I am sure there are similar products?
    Jeremy: Excellent point, I haven't done many of those types of shots, be interested to see the results - but I have noticed an increase in grain on some of the darker shots when creating the overexposed JPGs from the RAW file. Thanks for the comments!
    Tammie: No problem, glad you found it useful!

  • Tammie June 25, 2008 06:40 am

    Thanks for the in-depth writeup. Here are my first shots at HDR:

  • Jeremy Green June 25, 2008 05:18 am

    This is a good comparison. However it should be noted that the "generate 7 jpgs from 1 RAW file and then merge to HDR" technique only works if your scene is relatively LDR to begin with (like this one is). If you are shooting a scene that truly has a high dynamic range then this technique will begin to break down.

    Imagine standing in a a dark room with one small window out into a sunny afternoon. If you only take a single shot you (or the camera) have to decide whether to try to capture details in the bright part (out the window) or in the dark part (in the room) or somewhere in between. If you go for in between, then you will have a lot of blown highlights and darkened shadows that you will not be able to recover by generating 7 different jpgs. If you take a bracketed set, then you'll have nice details outside the window in your darkest pics, and nice details inside the room in your brightest pics. Then when you merge them all together you have good details everywhere.

    The point of bracketing your shots is to allow the camera to capture more dynamic range info than it can capture in one shot. By generating 7 jpgs from one RAW file you are not actually adding any new information. You are just moving the information that did get captured up and down the dynamic range scale. A properly bracketed set (of a scene with true high dynamic range) will contain far more detail than you can possibly capture with a single shot.

    Anyway, that came out longer than I thought it would. Nice comparison and write up anyway. I've done a few of these experiments myself and it's interesting to see how other experiments come out.

    Keep up the good work.

  • Paul Valach June 22, 2008 05:16 am

    Pity they don't want my money, or millions of others. I like the results but since they don't make a MAC version where PHOTOSHOP started, I can't use it.

  • Jason June 21, 2008 02:10 pm

    UPDATE: I've had a few people ask if I'd compared generating an HDR/tone-mapped image from a single RAW using Photomatix compared to the 7 exposure method generated from a single RAW I described above... you can see the results here.

  • Jason June 21, 2008 10:03 am

    FrankenPengie: If you really want to get technical, all HDR that you see on the web is faked - personal computers are incapable of displaying true HDR/HDRi... hence in the article I explained that for the purposes of simplification we would be calling the final image HDR as is popular, and not tone-mapped which is what it really is. When I originally wrote this, I had titled it HDR Battle Royale ;) - glad you found the info good though!
    Harry Phillips: Yes, this was a bit of a tough one to do considering the sun was behind those buildings... I haven't heard of enfuse, but I've heard of enblend - isn't it used to blend panoramas?
    elf_man: I find ReDynaMix good for some things, Photomatix for others... I actually find the ReDynaMix looks more cartoony in my opinion. Perhaps I could have used a different image for the test, the HDR/tone-mapping did bring out more of the dirt on the hood as well. I used this one because it was the only one that would align properly from my outing that day.
    Teewinot, choet, anamika, Bill: Glad you found it informative and (hopefully) useful!
    Barney: Excellent additional points, if I could I'd prefer the triple RAW merge every time but unfortunately I'm not steady enough and well over half my HDR attempts this way result in ghosting... and yes, Photomatix has a bazillion settings, but once you get the hang of it!
    ziad: yeah could be the card definately. I don't have an extreme or high speed on my XT at all and I can do 4 or 5 shots before it lags... which isn't a big deal because it can only do 3AEB shots at once anyways.

  • ziad June 21, 2008 09:22 am

    Re: Continuous shooting

    I was shooting an HDR sequence the other day and my canon 30D was lagging behind and therefore increased chances of misaligned images and ghosting.

    Maybe it was my flash card, not sure. So be aware of that.

  • Bill June 21, 2008 08:22 am

    I found this to be a very interesting read. I'm new to HDR and this answered some of my questions. Thank you.

  • anamika June 21, 2008 01:11 am

    Wow! Great post Jason. I've never read a better step-by-step instruction/explanation of producing HDR images. This gives me some incentive to try this out on my own.

  • Barney June 20, 2008 06:18 pm

    Good primer on HDR. Several things to consider:

    - Set your camera on continuous shooting when doing multiple exposures and just hold down the shutter to get your three exposures -- unless you have a tripod. Be sure the -EV is fast enough that you can still hand-hold the camera.

    - Both CS3 and Photomatix will attempt to align images and even move things slightly to fix that ever-so-slight movement when hand-holding multiple exposures.

    - Tone Mapping via Photomatix (both the application and the plugin) has a bazillion settings that take a while to learn. The subtleties of the settings are endless.

  • choet June 20, 2008 02:52 pm

    Thanks Jason a very interesting read

  • Teewinot June 20, 2008 07:52 am

    Very comprehensive and useful article, Jason! Thanks for sharing.

  • elf_man June 20, 2008 01:16 am

    I agree with Harry Phillips.
    The ReDynamix results look the best to me. The others have a little more detail, but it avoids most (not all) of the ugly haloing and OMG IT'S SO IN FOCUS cartoon look.
    This was a photo that does not need HDR. With the possible exception of the BMW logo, it was all captured by the camera's dynamic range, and you could've fixed that by just underexposing half a stop and bringing up the dark end later.
    HDR should not look different from normal. It should look like a properly exposed image. If you've killed the contrast and turned the saturation up to 11, you're doing it wrong.

  • Harry Phillips June 19, 2008 05:15 pm

    All of these suffer the fake 'halos' of all HDR images I have seen.

    Real tone mapping can be done with the Linux only program 'enfuse'.

    Have a look at my blog post on how I used enblend to create this photo:

  • FrankenPengie June 19, 2008 03:31 pm

    Sad. This should be titled "How to Fake HDR and Make it Look Good".

    Good info though.

  • Jason June 19, 2008 03:19 pm

    Jozef: No problem! Thanks for the links on GIMP, am sure others will find those useful!
    Wendy: Yes, for the price the ReDynaMix plugin is a great tool!
    AC: yeah, as I mentioned, it's all the rage these days - I've been using it for awhile, and a lot of times it's so subtle you can't even tell - those are my personal favorites...
    Kosior: glad I could save you the trouble!
    David: Nice additional links there! Nice HDR on your DA there as well!
    Gamelet: It's your lucky day then! ;)
    Omid: Yeah, that's the one thing that always bothered me about HDRs was the halos... I usually have my light smoothing parameter on medium, high or very high (farthest right)... thanks for the comments on the post!

  • Omid Khalili June 19, 2008 10:34 am

    Good Post, especially the definitions at the beginning. I've checked with a friend of mine who does research in a High Dynamic Range Graphics lab and the first thing he pointed out is that the Halos you see between high contrast edges are an artifact that, although it looks neat, is improper usage of the tone mapping tools.

    In Photomatix, if you take the light smoothing parameter to the left, you'll get those Halos. They make unrealistic photos and typically gives you the "artsy" effect. Taking it to the right makes a more realistic image that is 'properly' tone mapped since it lacks the Halos.

  • Gamelet June 19, 2008 07:20 am

    Just when I was becoming more and more interested in HDR, two of my favorite blogs posted about it, DPS and PSDTuts.

  • David June 19, 2008 06:49 am

    To add Jozef's post on using GIMP for HDR, Make magazine ran an article on generating HDR images. The link is:

    The article provided a link for a GIMP plug-in that I've used with quite a bit of success. The exposure-blend plug-in takes 3 jpegs representing bracketed exposures of a scene and combines them using contrast blending.

    I have an example of the results using this plug-in on my deviant-art site generated using three separate shots at different exposures.

  • Kosior June 19, 2008 06:47 am

    Nice guide. I'm all in the HDRi for some time now. The thing is, I always wanted to do such a comparision but it always turned out to be too boring. But here's your guide. I don't have to compare the different processes :D Thanks for that !
    ..and I've got a few good HDRIs so far. If you'd like to chcek, they're on my flickr.

  • AC June 19, 2008 04:45 am

    Very well written article. While I personally think that HDR (or tone mapping) is overused, it makes for some great snaps when used correctly.

  • Wendy Piersall June 19, 2008 04:30 am

    Thank you, thank you, thank you for the ReDynaMix plugin! I didn't think anything was out there in that price range for my ancient Photoshop 7 (I think it even works with v.6).

    I may be happy on the creative end, but now I want to tinker with all of my photos and I might not get any of my work done! ;)

    Have to say I was super-impressed with what it can do with a single jpg. Just posted one on Flickr here.

  • Jozef Nagy June 19, 2008 04:20 am

    Thanks for the writeup. The general points remain the same no matter which tool or image manipulations program you use. I myself prefer The GIMP over Photoshop because it's free and meets my needs.

    For anyone else using The GIMP or who wants to try HDR without spending money on commercial tools, here's a link to HDR photography with The GIMP:

    There are also plenty of free GIMP plugins to help you as well.

  • Jason June 19, 2008 03:21 am

    Angela: No problem! Figured I may as well share my results...
    Reznor: Yes, that is correct, you can open a single RAW file in Photomatix but it doesn't give the same range as using multiple JPG's... maybe I'll toss up a comparison of the single RAW generated.
    sazzycrazy: no there isn't! Have fun.
    Phil, Jennifer: I tried that out, I didn't like it as much - but yes it's cheaper and works well also. Maybe I just need to play with it more!

    P.S. Darren & DPS Staff: Thanks for posting this!

  • Jennifer Zandstra June 19, 2008 03:16 am

    Awesome, didn't know about ReDynaMix. It's exactly what I've been looking for... sweet!

  • Phil June 19, 2008 03:13 am

    As an alternative to using Photomatix, try out the dynamic-Photo HDR software. It's window's only, but gives pretty good bang for the buck, cheaper than Photomatix, but the interface and tools are really cool. The demo version should get you plenty of ideas.

  • sazzycrazy June 19, 2008 02:38 am

    i was looking for this information, i will try some HDR soon. nothing to loose in trying :P

  • Reznor June 19, 2008 02:23 am

    If I'm not mistaken, you don't need to generate JPGs in Photoshop to generate a HDR in Photomatix, you can just open a single RAW file in Photomatix and are good to go. Try it out.

  • charles June 19, 2008 02:11 am

    good post!
    For those of you who like HDRI, take a look a Trey Ratcliff's work on
    Great pictures from all over the world.

  • Tina Silva June 19, 2008 01:35 am

    I just learned HDR from my class in school.

    Here was my best photo:

    Also you can see the original at:

  • Matt Tuley, Laptop for Hire June 19, 2008 01:17 am

    Nice! I agree that the image resulting from usng the RAW files is best, but the others are pretty good. I'm actually surprised bu how good the images from "cheating" with a single source file turned out to be. I'll need to go play around with that myself.

    That motorcycle shot is great. Is that one of yours?

  • Angela June 19, 2008 01:17 am

    Wow, this is really in-depth. Very useful, thanks for posting.

  • Dustin Barbour June 19, 2008 12:33 am

    The image created using the 3 RAW images definitely looks better than the others. Interesting comparison, though.