AdTech Ceramics fabricates high tech microelectronic components in Chattanooga, and this spring I was asked to create a new portfolio of images showcasing these amazing products. The photography brief outlined a look that was more modern and clean than their existing photography, and which conveyed a high level of precision which reflects their delicate manufacturing process. Analogues for the desired look included high end timepieces and Apple product photography.
The brief presented a few challenges. First, many of these products are very small—only a few could be measured in inches, and the smallest could be blown away simply by breathing on it. The magnification from a standard macro lens wouldn’t be sufficient to create the production-sized images we needed. Second, photography always involves a balancing act between depth of field, light, diffraction (sharpness), and other factors. At high magnifications, each of those factors is pushed to the extreme, making the balance much more delicate. And finally, macro work with this kind of subject matter and background requires a lot more post-production than usual, because there’s only so much you can do to keep the set clean. Read on to see how we addressed each of these issues, and then visit the AdTech case study to see many more final images from the shoot.
Lenses specially designed to photograph small objects are called “macro” lenses. But most macro lenses are built to give a magification of 1:1—meaning they’ll fill the image with an object about an inch across. To increase the magnification of my 105mm macro lens, I used a set of tools called extension rings. In the same way that moving a projector away from a wall enlarges (but dims) the image, extension rings increase magnification by moving the lens further away from the sensor. The extension rings helped us capture the detail we needed from the smaller pieces.
But like a farther projector dims the image, extension rings dim the light traveling from the lens to the sensor, exacerbating one of the tradeoffs already present. Macro photography shortens the depth of field, meaning a very thin slice of the image is in focus at any one time. Extension rings compress that range even further. The first step to deepening the in-focus area is to stop down the aperture, but that comes with two tradeoffs of its own. First, smaller apertures let in less light, and we already have reduced light from the rings. Second is diffraction introduced by very small apertures. Lenses are sharpest towards the middle of their aperture range: a perfectly in-focus image will be a little softer at ƒ2 than at ƒ8. As you stop down to ƒ22 and beyond, the diffraction of light passing through the small aperture softens the image again. The amount of softening varies enormously by lens design and quality, but in this situation even an astonishingly small ƒ57 aperture would only keep part of the subject in focus.
Balancing and overcoming these trade-offs required a couple of solutions. Of course we’re lighting theses subjects anyway, so turning up the power of the strobes was a good first step. The close working distance let us really use the power of the inverse square law (moving a light twice as close to a subject makes it 4 times as bright). To offset the huge relative size of the lights in that situation, a specially cut set of small flags, diffusers, and reflectors helped block and shape the light which hit each subject. Not every image needed deep depth of field, but for the ones that did, I experimented to find an aperture small enough to give a good working depth, but not so small that it introduced diffraction problems. Then I created a focus stack—a series of images that record the same image with different slices in focus. Those images are later combined in post to create a composite with sharp focus from front to back. This is the same process used for Apple’s product photography, and the deep focus causes the photos to be frequently mistaken for computer renderings.
The the primary goal is always to accomplish as much in-camera as possible, what happens after the shoot can be just as important. That’s especially true with small products like this. The standard level of post-production I include free of charge with every shoot is designed to get the images created in-camera ready for production. That means adjusting contrast and overall tonality, broadly brightening and darkening the backgrounds as needed, and removing any sensor dust I missed during my pre-shoot cleaning (apertures this small turn even the tiniest sensor dust into a solid black mark). With this shoot, a further level of retouching let us clean up parts of the image that were too hard to control on set. I used a blower to remove as much dust from the product as possible before every shot, but many of these were so small that they would have blown away under a strong wind, so any excess cleaning had to happen in post. And for the few images that needed it, I completed a focus stack composite, each made up of 5-15 separate images.
Working at such small scales can be challenging, but I think it’s important to give the photography of a product as much care as its maker put into crafting the product itself.