In my earlier post, Derwent Water from Keswick, I mentioned visiting the viewpoint in Castlehead Wood. While I was there, I made a sequence of images to create a panorama but when it came to stitching it together, I struggled with the software I was using and was disappointed with the result, particularly eliminating the “seams” or joins. Recently, I made a useful discovery which changed that…
Ever since that trip it had bugged me that I hadn’t finished off the image. I mentioned it to an experienced photographer over Christmas, who told me that he uses Photoshop CS5 for most of his stitching work. The cost of CS5 is too high for me to justify it just for this functionality alone, so I set off to look for a dedicated piece of stitching software that would do what I needed. Apart from working well, my main criterion was that it was free or Open Source, or a minimal cost if this wasn’t possible.
One of the first candidates I came across was “Hugin”, an Open Source project which launched a full release in December 2011. At this point, I should say that this post is not intended as a full review of this software, simply to share what I’ve found so far.
In general, I’m a big fan of Open Source software. If there is enough interest from developers, a project can often result in an extremely useful tool to perform a particular function. And if there’s sufficient continuing interest, the software can be constantly developed so if there’s a feature you’re missing (and enough other people want it too) there’s a reasonable chance that someone will build it into a future version. It doesn’t tend to be constrained by any commercial bias, only the appetite from the community developing and using it.
One possible downside is that you can also end up with programs that create a huge array of options – not a problem in itself, but if the user interface isn’t well designed, or the documentation isn’t well written, that can leave them difficult to operate.
I have to admit, I’m not one for reading manuals, other than to find out what I need for a particular problem. So as I started up Hugin for the first time, I was hoping for a nice obvious interface – more on that in a bit – but the opening screen looked hopeful:
Having found a candidate for stitching my image, my workflow went like this:
- I shot RAW files at 24mm (on a full frame camera) in portrait orientation. I used 7 camera positions and took 3 images (+/- 2 stops) at each position. I was shooting on manual exposure to keep the exposures consistent for all of the sets of images.
- After downloading the RAW files off the card, I combined each set using Photomatix Pro 4 with the same white balance and tonemapping settings for each HDR image. The settings themselves aren’t important, but keeping them consistent is key.
- I imported the seven resulting TIFF images into Hugin, defining the lens as normal (rectilinear) and specifying the focal length used for the shots.
- I used the Align… function to automatically identify control points.
- In the exposure tab I selected Low dynamic range without white balance adjustment (I’d made this constant in the HDR conversion in step 2) and ran the optimiser.
- In the stitcher tab, I chose the cylindrical projection and the output to be exposure corrected, low dynamic range in TIFF format. The default remapper (nona) and blender (enblend) were left alone.
- Back in the Assistant tab, I clicked “Create panorama…”.
- I opened the resulting 32 bit (RGBA) TIFF panorama in Photoshop Elements 8, flattened the image to collapse the Alpha channel and re-saved the file as an uncompressed TIFF under a different filename.
- I then used Capture 1 to do some final adjustments (dodge and burn, remove dust spots, sharpen) and output to a JPEG for the blog using a standard recipe.
A Couple of Snags
I have to admit, I had a few problems. The first one was getting an output at all – it took me a while to realise that I had to click the “Optimise now!” buttons on the Optimiser and Exposure tabs for the panorama creation to work. It probably would have helped if I’d read that manual in the first place, really, but I did find that with all the options that were available it was really easy to switch something off or on that prevented me getting an output. The screenshot below should give you some idea of what I’m talking about.
My next problem was trying to write an output file when I had Capture One open. I realised that as Hugin was starting to write the output file, Capture One was detecting it and trying to list it, which locked the file and prevented Hugin from writing to it! In the end, the simplest thing was just to close C1 until I was finished.
The final major problem I had was getting Capture One to recognise 32 bit RGBA TIFF format that Hugin outputs. It seemed to manage OK with a JPEG but just wouldn’t recognise a TIFF, even though Windows 7 Photo Viewer and Elements could open it without any bother. After some testing and support from Phase One, I worked out that the problem was the transparency channel (the A in RGBA). To fix it, I added step 8 to the workflow above, to collapse the transparency data. The resulting file was picked up fine by C1.
I used the automatic processes throughout, but I felt that there was plenty of control available to help me deal with anything I wasn’t happy with. For all that I struggled with a few aspects of Hugin, I’m really pleased with the resulting image:
After my brief experience of Hugin so far, here’s what I’ve found:
- It’s extremely powerful – there is loads of dedicated stitching capability available, with plenty of control available.
- It worked on my troublesome image and gave a great result.
- Online documentation and tutorials are available to help with operation and functionality.
- Incredibly complex – it was very easy for a “tinkerer” like me to muck up a setting or miss a step and not get the desired result.
- The interface is quite “techy” – there are loads of options which are tempting to try out, but you might not know what they do (or might not do what you think they will!).
I only scratched the surface of Hugin in creating this image but despite its potential downsides, it is going to stay in my box of tools. I’m hoping that with more practice (and only a little more reading!), I can start to unlock the power of it.