Review updated and conclusions significantly revised 6Nov 2010; original review was overly critical of Nik EFEX, but the issue was almost certainly due to my own camera work!
Autumn is the time of low, cold bright suns. Those suns make a perfect subject for evaluating a number of HDRI (High Dynamic Range Imaging) applications.
Last week, I drove around the Peak district (UK) whilst taking a large number of shots directly into the autumn sun. I then reconstructed the shots as tone-mapped images using three different applications;
- Photomatix Pro
- Nik HDR EFEX Pro
- Photoshop CS5
I present the results of my trial below (as well as a few other test shots) as a flash review consisting of brief pro/con bullet points. The review is aimed at existing HDRI users, and I have kept it to brief bullet points under the assumption that you know the issues in HDRI, and standard HDR photography work flow. In fact, you probably only really want to know how good the just-released Nik HDR EFEX Pro is vs existing solutions, and want some insight regarding whether it is worth changing over to it.
The images below are shot to test particular important features of HDRI, as noted in the descriptions;
‘High autumn sun 01’ was shot with the camera on the ground using three exposures 0.7EV apart. The sun is to the upper right in clear air, and is actually too bright to look at. The challenge here for HDRI software is threefold;
- To ensure that the direct sun does not white out the sky
- To give some detail back to the road in the near ground (as it is out of focus close to the lens).
- To maintain realistic colour to the road and walls (which would otherwise tend towards bright blue).
‘High autumn sun 02’ was again shot directly at the sun, using three exposures 0.7EV apart. In this shot the big cloud has the sun directly behind it, and appeared a bright white. The camera is hand held, and there is a breeze on the barbed wire. The challenge here for the HDR software is;
- To remove ghosting in the wire between the three shots, without losing detail in the wire, and without blurring the grass texture around the wire
- To correctly merge the overall shots without adding motion blur, thus keeping the distant tower and treeline intact
- To add detail to the cloud surface.
It goes without saying that without HDRI we would see blown out highlights and clipped/banded shadows for both the above images.
Although HDRI can be used to for realism (i.e. to maintain a high dynamic range), it is also often used as a creative tool (enhancing textures and adding custom styling by using nonlinear tone map compression). HDRI can thus be used creatively to add movement or texture. The following two images illustrate examples of this.
In this shot, I am pointing at the low sun and trying to control the resulting flare via a circular polariser (i.e I am rotating the flare to ensure the longest streak is oriented with the adjacent tree, and also attempting to get a long diagonal streak top left to bottom right). I am doing this to (hopefully) give the scene a sense of movement. As this scene has a very large tonal range, I exposed across the entire range of the camera (12 exposures 1EV apart).
Issues here are;
- How easy is it to control unwanted aberrations (chromatic aberration) whilst increasing the ones we want (flare).
- how well did the application deal with the large number of files (12 4272×2848 images).
For the final image, I am using the fact that our house is currently partway through redecoration. It has bare, stripped walls. I thought it would be nice to bring out the textures of the walls through some extreme HDRI, to give a painterly effect;
Also, click here to see a larger image of the final composition (1200×800, opens in new window)
The issues here are;
- Ease in bringing out the textures in the image.
- Ease of controlling the main subjects of the image (shadow and coat).
- The composition relies on the lack of colour/texture in the shadow, and how it is offset by the big colour/texture in the coat and cushion either side of it. The intent of the composition therefore relies on the technical ability to control the colour/texture in these three areas independently of each other.
- Ability to add detail back to areas that would otherwise be blown out (i.e. the arm of the sofa and the bright sunlit areas on the wall)
Image created with 7 exposures 1EV apart.
This image is the only one of the set that is not a HDRI test; it is the only one that I consider to be a finished image. With this in mind its probably worth spending a little more time with this image, by also showing the brightest and darkest source images;
- Image 1: Photomatix and Photoshop (Photomatix used for tone mapping only, Photoshop used for post processing only)
- Image 2: Photoshop only (i.e. Photoshop tone mapping, and Photoshop post processing)
- Image 3: Nik EFEX (as a plug-in for Lightroom 3). No post processing in Lightroom.
- Image 4:Nik EFEX (as a plug-in for Lightroom 3). No post processing in Lightroom.
- Quick user interface (once you get to grips with it).
- Very good ghosting and Chromatic aberration reduction algorithms.
- The HDR tool of choice for many well known HDR photographers. Practically the industry standard in HDR creation (up to now).
- Although the manufacturer’s instructions are a little obscure, there are a few good books that concentrate almost entirely on Photomatix. I recommend Practical HDR by David Nightingale, the best of the several books on the subject that I own.
- Dedicated batch processing
- Interface is initially very daunting for beginners.
- Clearly written by programmers rather than photographers; some of the sliders are inter-related (e.g. you have to vary the gamma value after moving many of the main sliders, but this is not made obvious. This leads to a very large learning curve before you stop ‘just guessing’ and begin knowing what each control actually does.
- No advanced features such as curves or post tone-mapping contrast control. This means that you need Photomatix and another application (typically Photoshop or Lightroom/Aperture) to complete your tone-mapped images.
- Poor image zoom controls.
Nik HDR Efex Pro
- Shortest learning curve of all the available options.
- Nik have clearly learned from and fixed Photomatix’s inter-related sliders. All sliders in EFEX are easy to understand and show little inter-relationship.
- Full featured enough for advanced users, and has almost everything you need in a single UI.
- Brilliant, well thought out UI.
- The ‘UPoint’ Technology is a godsend for quickly spot-editing the HDR image without having to set up adjustment layers (Photoshop) or Adjustment brush areas (Lightroom). Even better, it allows you to adjust before tone-mapping so you maintain dynamic range.
- When you save, the whole HDR image is tone mapped and re-exported as a bitmap. This means that you lose all your settings, which is not too bad as you can save your slider settings as a user preset… but you also lose your UPoints! Ouch! An option to save the HDR file and UPoints might have made sense for pro users and professional photographers (who might have to tweak a complex image tone-map for the client, etc).
- Overuse of UPoints can sometimes introduce glow fringes (especially around trees or other complex objects) when you change the tone of the surrounding sky). This is caused by the UPoints and NOT tone mapping halos.
- Although the plug-in controls chromatic aberration (and usually does it well) you have no direct control of it. Nik EFEX generally tends to take control of many things behind the scenes, and this may be seen as a bad point for some users.
- Seems a little buggy when used as a plug-in for Photoshop CS5 (update; seems to crash occasionally if you do not load the exposures into PhotoShop CS5 before invoking Nik HDR EFEX… if you load the images first, it seems ok).
- Limited batch processing (you would be typically relying on Photoshop batch processing instead).
It is worth noting that althoughNik HDR Efex Pro is a plug-in and no shortcut is added to run it as a standalone, it does seem to works as a standalone if you run the executable file in the install directory (Program files > Nik Software > HDR Efex Pro > HDR Efex Pro.exe)
- HDR features massively improved since Previous versions of Photoshop.
- HDR features free if you use Photoshop CS5 anyway (and if you are serious in Digital Photography, you probably own PhotoShop already).
- Cheap if you already own a previous version of Photoshop and upgrade to CS5
- Allows you to do (or fake) most of the things that the other solutions allow, assuming you know Photoshop well.
- The fact that it allows you to save the 32 bit HDR file (and use non destructive editing) means that you can save (and later edit) intermediate steps in your project.
- The default settings tend to give very acceptable realistic HDRI images.
- Requires a very good understanding of Photoshop to use well.
- Tone mapping options a little limited when compared to other solutions.
- Expensive if you have to buy Photoshop CS5 (i.e. without upgrading), and certainly not worth it if you are doing it for HDRI only.
- Although Photoshop allows you to create a 32 bit HDR file, there’s almost no editing you can do with it without first tone mapping it first. In particular, none of the filters or dodge/burn work with a 32 bit file.
- Takes longer than either of the other two options (longer, more complex work-flow).
- Can produce massive files (and therefore requires beefy hardware)
Best use of each application;
Photoshop only: When you want to create a realistic image (i.e. when you don’t want to make it obvious that HDRI is being used).
Photomatix and Photoshop: Best tool to use when you have a difficult set of images.
Nik efex: Best general purpose HDRI tool overall. Best tool to use if you have Lightroom but not Photoshop.
For these results, I’m looking for failures that would stop the image being accepted as stock photography on technical grounds.
For the first image, all three applications did well. Surprisingly, all three applications produced good results very quickly, with Nik EFEX being by far the fastest. Photomatix required curve enhancements in Photoshop.
For the second image, PhotoShop would have failed as it could not fix the movement on the wire. I had to add the wire in manually via layers/clone tools to give acceptable results, and that took an extra 20 minutes.
For the third and fourth images, there was one outright winner: Nik EFEX. Only this application gave me the level of control (via UPoints) needed to control specific areas of the images. For example, the last image was less effective in either Photoshop or Photomatix, because I could not enhance the shadow and coat separately whilst still in the tone mapping process. Photoshop CS5 comes close, but all the close editing has to be done after the tone mapping, and you can therefore lose tonal range (the coat came out blown out in Photoshop whatever I did).
Fora ll three applications, a multi-core processor was seen to peak at 100%, proving all three applications are multi-core aware. However with large (or many) files, hard drive speed seemed to be the real bottleneck.
My current HDRI work-flow uses Photomatix and Photoshop together. I really wanted to like and move over to Nik HDR EFEX Pro, lose Photomatix, and stop having to post edit my tone maps in Photoshop/Lightroom. An almost impossible task, but Nik HDR EFEX does it.
The only downside to Nik EFEX are;
- You don’t get quite the same level of import control as Photomatix/Photoshop (albeit this is often better for work-flow; I have only seen Nik EFEX get it wrong once in about 50 or so images!).
- You can’t save intermediate states as you can in Photoshop. This means that once you save, you cannot easily tweak the image without running through the entire tone mapping process again.
- Although Nik EFEX is ideal for beginners in HDRI, the instruction pdf only tells you how to use the application. Some indication on how to actually photograph for HDRI would have been appropriate. This means that if you are new to HDRI, you will definitely need a HDRI book (but of course, non of them yet cover Nik EFEX). Catch 22.
The work-flow improvements created by Nik HDR EFEX Pro are substantial, but you do lose a little control at the same time. Although Nik EFEX is great for about 90% of my HDRI images, I’m still finding that I need Photomatix for about 10% of them, and this is mainly where the image has large amounts of Chromatic aberration (Photomatix seems a bit better for this).
Best use of each application;
- Photoshop only: When you want to create a realistic image (i.e. when you don’t want to make it obvious that HDRI is being used). Also useful to tone down a HDRI image by merging it with one of the original exposures (this is a common trick I use, and I need Photoshop to do this whatever the HDRI application I used). Best tool to use when you are prepared to spend a long time on your image (you can emulate most effects in Photoshop, given enough time and/or Photoshop skill). Photoshop also creates the most realistic (true to life) images, but on the flip side, it also gives least ability for creative tone mapping.
- Photomatix and Photoshop: Best tool to use when you have a difficult set of images, e.g large amounts of chromatic aberration. Also well respected in the HDRI community, with lots of literature on best use (almost all HDRI books cover it).
- Nik efex: Best general purpose HDRI tool overall. Best tool for creative use of HDRI. Best tool for new entrants into HDRI, because of it’s ease of use. Best tool to use if you have Lightroom but not Photoshop.