Adventures in HDR

March 28, 2010-1-blewittmergToday’s trip to High Rocks had me better prepared than last time.  I did some work on my shoes and replaced the battery sling on the Gigapan and set out.  My shoe laces broke and the Gigapan went apeshit, 0 for 2 so far.  So instead, I opted to practice some other techniques:

Thing 1 – Tonemapping

HDR (High Dynamic Range) photography is where one overcomes the limitations of a camera’s dynamic range (difference between brightest and darkest part of the picture) by taking multiple exposures at different light levels.  So, great, you’ve got an HDR image, the problem is that this simply passes the buck to our monitors which are also not HDR.  So one uses a process called tonemapping to compress that dynamic range.  Tonemapping can create something that looks closer to what the world looks like or blow it out to something a bit stranger.

So, here’s a starting picture:

March 28, 2010-16-Climbing

Here’s the tonemapped version:

March 28, 2010-16-Climbing_tonemapped

For starts you can simply make out more detail in the very bright areas (the sky) and very dark areas (rock crevasses).  Sometimes it just looks like you used a lightwash (flash) but the vividness is cranked up in a way adjusting saturation won’t manage.

So here’s a look at the types of tonemapping.  Here’s a source image:

March 28, 2010-164-Climbing

Here’s a trippy/acidy/blownout/overdone version that it sometimes associated with tonemapping:

March 28, 2010-164-ClimbingAnd2more

You’ll note that the very dark areas and very light areas are brought in such that the sky now appears less bright.

Here’s something more reasonable:

March 28, 2010-164-ClimbingAnd2more2

Tonemapping also has some limitations like when it’s rendered to jpeg.  Jpeg’s lossy and I should probably stick to TIF to reduce the compression.  The following image looks more apocalyptic and less poorly painted in the original.  I think the sky’s acceptable:

March 28, 2010-200-ClimbingAnd2more

I generally don’t like black and white photos and am not very good at taking them.  I don’t have the eye for color value which is what actually shows through.  Below is an exception:

March 28, 2010-146-Climbing-2

Here’s the root image:

March 28, 2010-146-Climbing

Here’s the tonemapped version:

March 28, 2010-146-ClimbingAnd2more

I think a little rotation made the photo a lot more interesting:

March 28, 2010-146-Climbing-edit

Action Merges

Action merges are where one takes many pictures of a particular action and merges them into a single frame.  This is a mediocre one of Mike Blewitt repelling:

March 28, 2010-1-blewittmerg

I did a sloppy job with merging the rope.

Here’s a better one of Sam climbing the face:

March 28, 2010-1-sammerge