HDR
March 2010 (index)
A photograph; and not a very good one. Lots of the detail has been lost. The window on the left is bright white in places with no sign of the lead between the panes; and the foreground has lost the rich detail of the wood grain.
At 1/4s exposure
It's hard to remedy this. The next two photos were shot at the same settings (f11 and ISO400) but changing the exposure times: 1/30th of a second on the left and 4 seconds on the right.
At 1/30s and 4s exposure
On the left we can now see the detail of the windows, but everything else is too dark. On the right we can see the detail of the pews, but the rest is too light. The problem is that there's just too much variation in light intensity ("dynamic range") for a typical camera to cope with, even though our eyes could do just fine if we were present at the scene.
There is a way around this. We take several photographs at different exposures (shutter speeds of 1/30, 1/15, 1/8, 1/4, 1/2, 1s, 2s, 4s) and then use some cunning software to make sense of all this information and turn it into an HDR ("high dynamic range") photo that looks good to our eyes.
Here's the result from doing just that using Hugin (and then tidying the colour balance with Picasa ). This image has rich detail from the pews to the windows.
The HDR image (click for large version)
Hugin describes itself as a "Panorama Tools Frontend" and can stitch several overlapping photos into a panorama; but it copes just as well with one scene at different exposures. It can also correct perspective so one added advantage of the final image is that the walls on the right and left no longer slope inwards.
ibbly.com contact