Flowers and extension tubes, and how they work together

Here's a photo of an impatiens that I have at home.

I somehow managed not to kill it last year despite a month of mold remediation to get ready to sell my house followed by several months of neglect while still getting ready to sell my house. It seems to be doing pretty well in Arlington. I water it once a week or so and feed it coffee grounds every so often.

The photo is pretty, I suppose, but nothing special. Canon 40D, 50mm f/1.8 II lens, 1/25 sec at f/8, ISO 100. I reduced the photo (and the others in this post) to 25% of original in both dimensions, but otherwise they're straight from the camera, with no postprocessing. For all the photos, I used a tripod and remote shutter release to reduce camera shake.

So look at this.

Same part of the same plant, same camera, same lens, but this time with a 20mm Kenko extension tube between the camera and the lens (1/500 sec, f/1.8, ISO 400). That enables you to move the camera and lens much closer to the subject. I love how the petals become almost translucent.

So look at this:

Same part of the same plant, same camera, same lens, but this time three extension tubes (12mm, 20mm, and 36mm), plus a Canon 1.4x II tele-extender, and mirror lockup since camera shake is an even bigger problem in this range. A little known bonus of using extension tubes is that you can use a tele-extender with lenses that normally don't fit with one. Not always useful, but sometimes it is. This was 1/2 sec at f/8, ISO 100.

I would never have even guessed that this was in there. I think the star-tube things are stigmas (apparently not "stigmata" ... that's a different kind of stigma), and the green cucumber-looking thing is the ovary; this is confirmed by another blogger in Alaska (http://whatdoino-steve.blogspot.com/2010/07/ufos-in-my-garden-more-flowers-and-bugs.html), who also admits that he doesn't know what he's talking about. Any of you flower people out there, please feel free to correct me in the comments. I'm a camera guy, not a flower guy.

One downside of extension tubes is that the depth of field becomes very shallow. Even at f/8 it was hard to keep the stigmas and the bottom end of the ovary (if that's what they are) simultaneously in focus. But overall, I think it's pretty amazing what extension tubes can do to flowers.