Maintaining Focus

“If your pictures are not good enough you are not close enough.”
Robert Capa

As mentioned in my October, 2021 article, the year delivered a bumper crop of berries, typically snowberry (Symphoricarpos), chokecherry (Prunus virginiana), serviceberry (Amelanchier), and others. These are common on our property and pretty much throughout western Montana. The snowberry, especially, attracted my attention, mainly because the fruit is large, bright white against the summer-green or autumn-golden foliage, and, as mentioned, more than usually abundant. I didn't spend time in the mountains this year, but I wouldn't be surprised to learn the huckleberry crop, a Really Big Deal in Montana, broke records.

I've wanted to photograph snowberry in snow, perhaps because I like the idea of snow-covered snowberries. I didn't know how that idea might translate into a photo, but it seemed worth a try. Trouble is, when it's cold enough to snow, the berries often freeze and become unattractive and desiccated, looking like gray-white raisins against withered brown leaves. I've been watching and waiting for a day in a year when conditions favor snow during a period that's not been too cold for too long. Without a long sub-freezing period preceding the snow, maybe the berries would be in good condition while collecting a nice layer of ice crystals or snow.

In 2021 we had no snow in October, nor did we have the typical week or more of sub-twenty-degree (F) October days. November had brief flirtations with cold, temperatures a few nights dropping into the twenties, the days a little below freezing. And continuing this year's extreme drought here, no snow. Finally, during the month's final week, we awoke to two inches (5 cm) of heavy, sticky snow and a brilliantly sunny morning.

No Travel Required

I collected my gear and walked all of 40 feet (12 m) to the end of my driveway, set up with my 100-400 mm zoom and tripod, and went to work. I've found that lens (see our gear page) to be tack sharp, and it focuses down to about three feet (1 m), which suited my previsualized compositions. With my camera-to-subject distance in the four-to-five foot range (1.2 - 1.5 m), I didn't need an extension tube.

Nuthin's Ever Easy

But this would not be a simple shoot. Depth of field, or rather, the lack of it, provided the first complication. With the lens set to 400mm at f:/10 and at a scant few feet from the subject, the area in focus is extremely shallow, perhaps little more than half an inch. Stopping down to, say f:/16 would provide only a little additional DOF, but soften the images due to diffraction. The subject's depth would be eight to twelve inches, determined by how much of it I wanted to be sharply focused.

To work around the equipment limitations I'd use focus-stacking, a technique I've used with varying levels of success on both close-up pictures and wider landscapes with close foreground objects. In principle this is simple: manually focus on a part of the subject that's to be sharp in the final image, and make the exposure. Refocus very slightly on the next “layer,” make that exposure. Continue until enough frames have been captured so all of the subject has been covered. I typically start with the nearest part of the subject and work my way back. The resulting image files are processed into an image stack, the software (on a good day) aligning each frame and masking out the soft parts, leaving the sharp areas visible. The final picture (on a good day) has all of the desired elements sharply focused, the rest of the image softer or completely out of focus. When everything is just right, this works pretty well.

Things often aren't just right (OK, things are almost never just right). If the subject moves while making the exposures, it's likely the software will struggle, and probably fail, to align things in the final stack. And of course, when working outdoors things move, sometimes a lot, even in a whisper of a breeze. The light can change from frame to frame. Shadows come and go thanks to moving clouds, trees, and other obstacles between the subject and the light source. These things can be handled if one is willing, and has the time, to clamp the subject to out-of-view supports, and use artificial lighting. At some point you have to ask yourself 1) How badly do I want that photo?, and 2) Am I having fun doing all that setup? Your answers may be different from mine.

The second complication: the subject itself can change, as happened while I worked on the snowberry captures. As mentioned, it hadn't been too cold, and the mid-morning sun quickly warmed my subject. Chunks of snow periodically fell away from the berries, which not only changed the subject itself, but also unweighted it and caused it to move. My subject location, under the lower branches of a small (15 feet/4.6 m) Ponderosa pine, may have been less than ideal. The tree's shadows moved across the subject as the sun rose higher, and snow melted out of the tree, falling in big, wet, cold dollops all around the subject. And on me, which didn't move the subject, but surely made the photographer jump.

I could do nothing about any of that, except work fast, do some sequences of captures over, and hope for miracles later from the software.

Don't Depend on Miracles

I opened and quickly scanned through the raw files in Bridge*. A few of the sequences of images looked pretty good. My favorite composition was the last I'd done. It had thirteen files covering the field depth I wanted. In one of the frames the subject clearly had moved, but I couldn't discard it; that would have left a gap in the sharpness across the field. I processed the middle image of the stack in Camera Raw, applied that processing to all of the files, and then saved the files. Back in Bridge I selected all and then passed them on to Photoshop's Photomerge application. This is supposed to automatically align the images and then “seamlessly” blend them, creating masks for each layer to reveal the in-focus areas of that layer, hiding the out of focus (OOF) areas. It didn't, instead making a mess of the image, with holes and gaps, large OOF areas, and blurred areas of misalignment. I've seen this happen before when using this process, but I usually give it a shot, expecting it to fail as it usually does. Hope for the best, plan for the worst.

Back in Bridge, I selected the files, and then opened them in layers in Photoshop. I then used the alignment feature, followed by the blending feature. This is what the process in the previous paragraph is supposed to do. I've learned that invoking these individual steps manually nearly always works better; this case only reinforced that belief. It worked better, but not especially well.

With thirteen layers, it's very difficult to manually edit each mask to conceal the OOF areas and reveal the in-focus parts. Instead, I selected just four of the images, aligned and blended those, and then in pairs aligned and blended additional frames, merging those pairs, and then aligning and blending them to the previously done layers. This seemed promising, but still required considerable manual work painting in the masks of each additional pair of layers. After about four hours I gave up on the task, and I've pretty much given up on the picture.

Once More, With Feeling…

Snowberry in snow on a sunny November morning.

The simpler, four-image stack.

At this point I was tiring of the effort, and not remotely sure the picture was even worth it. But one more attempt, this time with a simpler grouping of a different bunch of berries. With the smaller subject I had only four captures in the stack. In hindsight a couple more might have been better, but the nice light had passed, the snow melted, the subject gone. I could only work with what I had. This time I repeated the manual alignment and blending as previously described. This created a picture with a few small OOF areas, but otherwise not bad. I spent the next two hours cleaning up the masks. I also cropped out areas that might have been covered by additional frames I didn't capture. In the end, an OK photo, I think, but again, I'm not sure it's good enough to justify the time spent.

Some pictures are easy, some aren't. My skill level is sometimes up to the task, and sometimes isn't. Either way, I often learn something in the attempt.

November, 2021

*I'm the only photographer I know who doesn't hate Bridge, a component of Adobe's Photoshop bundle.

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