The 42 foot wide Liverpool Skyline HDR

Old 15 Aug 08

I’ve posted a photo of this image before on my 365 blog, which is currently undergoing tweaking. I thought it might be nice to properly show the image and discuss it a bit. You always see people discussing megapixels on forums and what you can print to. People saying they have a 8mp camera and it does A3 nicely. Which is fine for family portraits and things but when a client asks you to produce something 13 meters, 42 feet wide from an 8mp camera you of course say yes. I’ve printed to 1 meter before now without issue. The prints look great. So 13m? Easy. Ok so maybe not easy. You read articles about 50mp Hassleblads with sensors the size of TV’s that people use for advertising, for billboards. You never in your right mind think that you can use a simple mid-range DSLR with only 8mp to produce something 42 feet long and 9 feet high. Something that ends up being a 1/2 gigapixel image. Never say never though.

After chatting with some friends about the best way to acomplish this it was decided a panorama was the way forward. There was no way that my Sigma 10-20 would be able to resolve enough detail at 42ft wide from 1 image. Not only that but the aspect ratio wasn’t right for a single image. So a pano it was. That made things easier. 9 meters wide and I’ve printed to 1m before now so thats just 9 images right? Not exactly because its also 3m high. So thats 27 images. 3 panoramas. Tricky, but doable. Trickier for one reason though, HDR. To do a solid HDR tone mapped image you need at least 3 exposures. So that takes us up to 81 photos. Oookay, ow. Its tricky enough trying to produce 1 panorama not just 3 so you can make one large one. No worries, I eat stress for breakfast. At least I would if I ate breakfast and it came as something chocolatey.

I had two ideas for the final shot. Sunset over Albert Docks and the Liverpool skyline. Sunset over Albert Docks was easy enough to shoot. It just took the right sunset to nail the shot. While working I found that I couldn’t quite get the 81 images quite right. I felt that they weren’t lining up properly. It was sorta tricky trying to keep it all in my head as I was working off lining up each shot via the focus points inside the camera. Trying to keep track of where I had lined everything up was not working. So I focused on creating one solid panorama. Instead of landscape images I went for portrait using the 24-70. This way I would stand a better chance of getting more detail in the shot. It was a little more awkward getting the Liverpool skyline shot though. I wanted something that no-one had ever done before. Liverpool skyline at sunrise in HDR. I wanted to retain all the detail in the buildings while having a stunning sunrise. As you can see though that never happened. I spent nearly a week getting up at 3am to take the photo. Day after day of rubbish sunrises. My deadline was fast approaching so I had to admit defeat on that front. I went for sunset instead in the hope that the skyline would look stunning. I got lucky.

So for this I went with the 24-70 in portrait taking 3 images at each section. I went from the terminal at Birkenhead all the way to the Anglican Cathedral. The obvious issue being that to get the boat in I needed to be at 24mm which meant the skyline would be smaller than I had liked. But it added a nice bit of context to the shot. I think the final shot was around 33 images in total. So 11 images for the pano essentially. I HDR’d each section seperately using Photomatix rather than building the panorama first and then trying to HDR that monster. That was easy. The next part was creating the pano which I thought would be rather complex. Its not like I went out there with all the top gear for creating a panorama. One of those fancy tripods for example. No, I went out and winged it in the hope that my Mac would save me. I tried a few programs before I noticed that Photoshop CS3 had a panorama feature. “Why not” I thought. I threw the photos at it and damn. It worked. I honestly couldn’t believe it. For something that had 0 options beside load images it worked so SO well. There were no joins, no colour issues between shots, no exposure issues between shots. It was simply 1 image.

Now the tricky part. I was working with an image that was quite large and I had about 2gb free. Applying any adjustment layer to this image meant that that 2gb was gone instantly. I had to move my entire mp3 collection off my local drive which gave me 40gb to play with. I was working with an image 16809px by 3529px, which isn’t exactly *that* large but I only have 2gb ram so it was sluggish. The end photo needed to be closer to 50,000px wide. I had to do some processing to the image as I felt it needed tweaking. Annoyingly if you see the final piece you can make out where I’ve done a bit of work because the brush size is the size of your head in real life. To get the image up from 16,000px to 50,000px I used a program called Genuine Fractals. I’ve used it before and its really good but the one major limitation is that you’re looking at it on a 15” display. Sure it looks fine there but is it going to look good once its hung on the wall 42 feet wide or are you going to get a call from a very irate client? I put in the measurements and set it off. The first time it failed because it ate about 20gb of free space I had left. I moved everything I could off and set it to run again. It took ages and didn’t run out of space thankfully. I was left with a 2gb image. That’ll be easy to email I thought. At least it was 2gb uncompressed. Once I saved the jpg it was down to around 400mb which was fine for uploading. Still, about the biggest image I’ve ever worked on.

The client was happy and I waited for it to go up. They printed as wallpaper and applied it as such. The client being Pizza Express and their new Liverpool restaurant at Albert Dock. A prime location right opposite the new Echo Arena. So not exactly something I could mess up. I got a call saying it was up and looked great. Yey. I went along to see it and holy moly what a result. Its about the length of a bus, perhaps longer. Incredible really. The detail is quite astonishing too. I expected at least some pixelation but theres none. It really is fantastic to see, if I do say so myself. So props to Lightroom, Photoshop, Photomatix, Genuine Fractals and to Liverpool for making a rather nice skyline to photograph.

Comments 6

  1. Rob Louw says on 30 Sep 08

    I note that you produced HDR images (presumably using Photomatix software?) of each set of photos before merging them into a panorama. The question I have is did you use the default Photomatix seetings for the HDR conversion and then save the resulting image as a TIFF or a JPEG file? Presumably you applied no further adjustments to the HDR images in Photoshop before creating the panorama? What Photoshop adjustments were made to the panorama after it was created? How long did it take to stitch it together?
    I have tried assembling an HDR panorama myself but took a different approach. I first stiched the the sets of three exposures together into thre panoramas and then tied to merge them to HDR. Not surprisingly this method failed as each panorama had a slightly different number of pixels.
    I plan to try your method in London this weekend. Are there any other tips which you could offer?
    RAL

  2. Erik Zimmerman says on 30 Sep 08

    Pete,

    Great shot, I love it!

    I’m a little confused regarding your technique. You mentioned you shot the HDR pano in portrait, but in your Lightroom screenshot you show them in landscape. I’ve always read that when shooting panos you should shoot portrait mode – is that a myth? Did you have better success shooting landscape?

  3. Pete says on 30 Sep 08

    @Rob Louw – I tone mapped them in Photomatix using my normal settings and saved them as a JPG. I then built the pano in Ps and edited it further. I think it took under 5 minutes for Ps to work its magic.

    @Erik Zimmerman – Thats a typo. I shot one pano in portrait and one in landscape. They chose the landscape pano. I will correct that. Shooting in portrait does allow you to get more detail because it requires you to take more photos for the wider shot.

  4. Rick Larsen says on 2 Oct 08

    Pete, Great work! Truly great! I am amazed that you did a 9×3 without an indexing head. I have one I built from Manfrotto parts, but greatly improved on some of their machined components. I tried a few multi-row shots by hand and gave up and went to an indexing pan head. I use the head for pans, but also for large format outdoor shots like 7×6 frames and more. The way you did the HDRs is the only way I’ve found possible. Stitching distortions are not the same from image to image, so the HDRs must be combined before stitching. I typically do 30 to 40% overlap, especially for images that lack detail or contrast.

    A lot of my shots are waterfalls here in Tennessee, and the falls, like your ocean, lack synchronized points for the software to lock onto, so I have to do occasional hand stitching, although PTgui does work better than any other software I’ve tried. I often have a lot of very close foreground, so my camera and pan head are calibrated for precise rotation around the exit pupil.

    Like you, I have had great results with Genuine Fractals for taking large pans and making them larger. The results never cease to amaze me.

  5. Vibhu says on 8 Feb 09

    This is quite an economical way that you’ve detailed. Thanks for that; encourages the others to lighten their work process, or just experiment.
    I’m surprised that the 8MP print, stretched out to 1m both ways, was detailed enough. What did you keep for your focus point and how did the depth-of-field come out? I can’t say anything much from the (much, much) smaller versions posted here :)

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