Sunday, April 19, 2015

Closer, CLOSER, no - CLOSER!

My friend and fellow blogger, Ken Spencer is getting a complex. To hear him tell it, whenever he uses his macro lens, I'm a little imp whispering in his ear to "Get Closer!" While I generally don't think that way, my motivation for getting close is that the subject often reveals interesting details when you get really close. So something boring can be often quite interesting!

Case in point was our fish hook barrel cactus in front of the house.  We've got two pretty good-sized versions in our yard, they've been there for a couple decades,  Interestingly, the large one blooms in the Fall, the smaller one in the springtime.  Well, the smaller is blooming right now, but the cactus dome is so full of spines that the flowers are too crowded to be interesting or pretty.  However, there is a little window of opportunity if you zoom in and get close - REALLY close!

Shown at left here is an individual frame shown in the above setup. I used the 100mm macro lens, and to get closer still, used a 36mm extension tube that allows even more magnification. You've got to use a tripod at these magnifications, fortunately, the barrel cactus is pretty impervious to the breeze that was blowing - no problems there. But at that magnification, the depth of field is quite small - only one narrow plane is in focus at any one time, even though I stopped down to F/9.  Stopping down even more would increase the depth-of-field, but resolution actually goes down because of diffraction. I've talked about the solution before - focus-stacking! By taking several exposures at different focus settings, Photoshop is used to combine just the in-focus parts of each image. The image at right is the result - almost perfectly in focus from the top of the yellow stigma, to the bottom of the anther stalks!

I worked on another example today. I've posted some of the pretty flowers of the Desert Globe Mallow before. Well, the flowers are long past, but even the dead-looking branches are interesting when you zoom in on the seed pods! For this shot at left, I used the same setup as above, but used the full stackup of 68mm of extension tubes to magnify as much as I could. For a sense of scale, the seed pod is about 8mm across, about 3/8 of an inch. This was an 8-frame focus stack also at F/9. Note the peach colored flower dehydrates into the pale pink at upper left. Since I can't show the full resolution image here (limited to 1600 pixel images), shown at right is a crop of the full-rez focus stack. I like the resolved fuzz and spider silk stretched across the ultra-closeup.

So when you are shooting something that might be a little bland - move in closer for more details! While dedicated macro lenses are expensive, extension tubes are inexpensive and allow focusing a lot closer than the limits of your normal lens. Happy hunting!

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