Cactus Spines

I have been fascinated by the spines of this Echinocereus species cactus at Phipps Conservatory for some time. In fact, I have taken several photos of it in the past but have never been happy with the images for one reason. The spines are so long that when I fill the frame with them using my 180mm macro lens it simply isn't possible to get all the needles sharp along their entire length, even at f16 or f22. The depth of field just isn't great enough. 

I really should say that it isn't possible to get them all sharp in one single frame. Last weekend I took out all the stops and brought along my macro rail. The rail lets me take a series of tripod mounted images without refocusing, by manually moving the entire camera and lens closer to the subject as a unit, bit by bit. As the lens moves closer to the subject, a different area is brought into focus. 

I took 35 shots, each spaced 1mm apart (probably more than I needed to) and combined them using Helicon Focus focus stacking software. The software uses computer algorithms to take the sharp parts of each of the 35 frames and combine all of these sharp areas into one single image.

The result is shown below, converted to a sepia toned black and white photo. Those needles deserve to be shown in sharp focus throughout their entire length. And those tips are mighty sharp!

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Cactus Spines    © Howard Grill

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