Lavender Blossoms, Up Close
Another macro photograph, this time some deep purple blossoms from our back yard
This is some of the more colorful lavender from our yard—a lot of the lavender that the bees love have only a few blooms on the stems. This variety still has a lot of blooms.
This is a composite photograph, made from 51 photos, each at a slightly different focus position. Any single photo only has a small area in focus, but when I stack them all up, everything in the range is in focus as you see it above.
Here’s an extreme example, the frontmost portion of the raceme, with a tiny part of one blossom in focus:
Here is a crop at 100%, showing what the details look like at full size (the image at top is 50% of full size).
The halo you see around many of the details is an artifact of focus stacking. The out of focus images leave that mark on the focused images. It can be edited out (mostly) with some painstaking hand work. In particular, the lens I am using is fairly fast, which makes for really large out of focus images, so at some point I will get a lens with a slower (or at least adjustable) aperture to minimize this kind of artifact.
I have put together a special setup for my medium format camera to take these macro photo series. The technique is called focus stacking. I tell the computer that controls the movement of the camera where to start and end the sequence, and how far to move between shots. You want a good deal of overlap for best results.
This is the business end, a special type of lens. It is a machine vision lens—high sharpness, and designed to be used very close to the subject.
I have a ring light set up around the lens to illuminate the subject.
The ‘camera’ is a digital back attached to the rear of a bellows. The bellows stretches as I adjust initial focus on the part of the subject nearest to the lens. The controller then steps the camera back, bellows, and lens forward as a unit, taking a photo at each step. Step size might vary from 10 to 100 microns, depending on the magnification of the image. Higher magnification, smaller steps. Here’s what the digital back looks like:
The subject shown in that photo was an earlier heather attempt; there were hardly any blossoms compared to today’s post.
The digital back has a medium format sensor: the Phase One IQ3 100 megapixel back. A 35mm camera has a sensor about 24x36mm; the medium format back has a sensor about 41x54mm. The cable you see at the left connects to the controller, a StackShot; it moves the hardware on a linear stage not seen in the photo.