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Daily Archives: November 13th, 2008

It’s got a bit of a silly name, but then so has Qtpfsgui. At the moment though, Dynamic Photo HDR is my HDR weapon of choice. Aside from running flawlessley on Linux under Wine (it has a ‘platinum’ rating on WineDB), it has a range of different tone mapping algorithms, good image alignment controls, anti-ghosting tools, support for 360 degree panos, and some options to improve sky and skin tone quality. It’s also fast, and free – well, not quite, but the demo version is fully functional other than putting a logo on the bottom of your image and preventing you from saving the HDR file (you can save the tone mapped image though). If you add some extra space on the bottom of your pics before you process them you can just crop the logo off at the end. If you’re going to buy it, I think $55 is really good value. I haven’t yet but I probably will.. it’ll be the first Windows program I’ve bought with the intention of running solely under Wine, which is testament to the progress the project has made.

So, to get going with HDR you’ll need 3 bracketed shots. In this example I’m using a planet stitched together from 7 photos, bracketed at 0EV, -2EV and +2EV. Download the examples here. I stitched the 0EV planet in Hugin, then I edited the .PTO file and replaced the images with the -2EV ones, stitched, then repeated for +2EV. You end up with three planets that are in perfect alignment:

3 planets

Next, fire up Dynamic Photo HDR, create a new HDR image and add your three photos then set the EV values accordingly (if you’re using photos straight out of your camera I presume it’ll read the exiv data automatically). Instantly you’ll have a preview of how your HDR image might look in the end.

hdr select images

If your images are already aligned you can skip the next step. If not (e.g. you’ve shot your bracketed set hand held) then you may need to align your images manually. This is pretty easy with the scroll dials provided. You can also use the paint brush tools to create anti-ghosting masks where something has moved in between shots. This is also quite straightforward.

hdr align images

Once you’re done with alignment/anti-ghosting, hit the ‘tone map HDR’ button. This is where the fun begins.

hdr tonemap

Chose a tone mapping method – ‘eye catching’ gives pretty dramatic results. Then adjust the settings to taste. When tone mapping images with lots of sky, there can often be patches of noise that stick out. Hit the sky 3D filter and these should be ironed out. The skin filter helps make skin tones look more realistic. On the right hand side there are some options for gamma, curves, colour and hue control, and at the bottom there are some colour temperature settings. If your image is a 360 pano, be sure to hit the ‘360 Pano’ button to ensure that the two end of your pano blend seamlessly. When you’re happy with the preview, save your settings (the ‘s’ button), then hit process.

sunset hdr

Et voila! Pretty easy I think. In this example I wasn’t that happy with the skin tones in the end, so I overlaid the HDR image and the -2EV image in Gimp and used the erase tool on the faces. I adjusted the colour balance and the brightness on the -2EV layer before flattening the image.

London is an expensive place to live. As a tourist though, there are a few perks, one of which is free entry into London’s museums. If you’re visiting I’d suggest checking out the British museum, and in particular the Great Court. It’s a quadrangle covered by a vast tessellated glass roof, surrounding the circular reading room, and is supposedly the largest covered square in Europe. It’s a very impressive space so don’t miss it. Luckily for me the British museum is about two minutes from where I work so I often short cut through when I’m grabbing my lunch. The other day I took my camera with me and ended up with one of the most bizarre planets so far.

great hall

Things get even stranger when you pitch it 180 degrees.

great hall inverted

Another place well worth a visit is the Natural History Museum. I’ve been there every year for the past couple of years for the Wildlife Photographer of the Year and intend to go pretty soon for this year’s exhibition. There’s another impressive central hall here too; this one contains a large Diplodocus cast which I think would look pretty cool in a little planet.