R U Ded?

When I was unpacking the Sempervivum order January 29, a loose little ball rolled out. With the webbed fluff on the leaves, apparently it came out of the Arachnoideum (#1) pot. It looked dead, but after my recent reading on succulents I knew not to assume that. When in doubt, stick it in some soil and see what happens.

The first three images I took of it were out of focus, which made me a bit peeved. I said to myself, "Self, you have the most powerful mirrorless camera in the world, a matched 100mm macro lens, Photoshop full edition AND a sturdy tripod." So I looked up how to do "focus bracketing" and blended 20 images (f/5.6, 0.8 second, 100 ISO) of this thing just to make sure I had it in focus. It is. These are two versions of the same blended image with different cropping. I still don't know whether it is alive, but I'm giving it every opportunity.

Twenty images is enough to get this little ball in focus, but the depth of field is still rather narrow. The camera will take up to 999 images. That would take a LONG time to stack in Photoshop.

It is not always necessary to use the in-camera focus bracketing, or to take dozens of images. Photoshop will take two or five (or 999) images and attempt to align and stack them. I took two images of this Sempervivum (#2) yesterday. As it turned out, one had the central rosette in focus and the other had the left and right offsets in focus. It wasn't intentional, but Photoshop allowed me to salvage the situation. The framing of the two images was not identical, but Photoshop took care of that by aligning them. If you look closely, there is still an out-of-focus zone between the front and the middle. Maybe three images would have been ideal, but given just two images it is better than either of the originals. There are other apps besides Photoshop that process focus bracketing and might be faster, but for me Photoshop is more than powerful enough.

The Next Day: I shot my newest cactus Mammillaria rhodantha aka Rainbow Pincushion using two different focus bracketing settings. The first one was 10 images with two steps in between (yesterday's was 20 images one step apart). The second was eight images with three steps in between. I think the second shoot had slightly more depth (8x3=24 is greater than 10x2=20), and a few more of the back spines were in focus. The danger is if there are too many steps between the exposures, there will be little bands that are out of focus. That isn't a problem here, and more experimentation could reveal when it would become a problem. But not today. I used backlighting from a window on this to emphasize the spines. To get all the spines in focus, I might have to go 12x3 or 8x4, something like that. This is the second image (8x3):

If you look closely, this cactus has fluff around the base of the spines, and I have seen some photos where the fluff is much thicker. It also has a long blooming season starting in the spring. I'm looking forward to getting perfectly in-focus images of fluff and flowers.