Monday, May 19, 2008

Out a snapping

Saturday was a bit of a wash-out, but Sunday morning was very nice so I hit the basins armed with my camera and a tripod. I'd been looking into High Dynamic Range photography; in essence you take the same picture multiple times, but with a different exposure. The idea is that at a darker exposure you gain details in the lighter areas and at a lighter exposure you gain details in the darker areas, combine them all with some digital wizardry and you end up with a photo that should represent better what the photography actually saw.

Anyway as you can guess taking multiple photos to combine requires either a camera with an automatic bracketing facility and a steady hand, or a tripod. As I have neither of the first two it's lucky I have a tripod :-)

So I parked on Raven Street took some shots of the Civic Centre, headed down to the Meadows to the bandstand and then along the river up to the basin.

So I took an Auto shot then 3 or 5 Program shots with exposure compensation from -2 to +2 which was a simple arrow back and forth.

Then I picked up Qtpfsgui an open source program that loads JPG images and outputs an HDR image. A quick play with that and tone-mapping produced not very brilliant results. I could have a play, but instead I'll try < ahref="http://hdrsoft.com" target="soft">Photomatix which seems to be the stand-alone HDR software that gets mentioned the most. It's £50 to buy, but you get an unlimited trial that slaps a watermark on the end image.

Looking at their examples I may have taken the images incorrectly, which might explain my results with Qtpfsgui. Anyhoo Photomatix has an Exposure combine facility so I've tried that and the results aren't too shabby although their file sizes are twice as large.

Si I'm uploading the two Auto photos followed by two Exposure combines and one HDR tone-mapped photo. I've just used the auto settings in Photomatix except for a slight tweak on the HDR.

As a final test I used plain old Paint Shop Pro and loaded the 0,-2,+2 photos as three layers and had a play with the blend functions. In this instance I ended up with Normal, Soft Light and Hard Light respectively.

I'll say the Auto is a good enough shot, the Exposure combines look a little more like what I saw, but personally I prefer the Paint Shop Pro version even if if does require some manual alignment tweaking (which I couldn't be arsed to do this time around). I'll still have a look at Qtpfsgui in an attempt to replicate Photomatix and save myself fifty quid, but at medium print size the Paint Shop Pro ones I think are fine. Heck I even get greater control and more things to fiddle with.

0 comments: