In the photographic world, we often strive to achieve a shallow depth of field for several reasons. For example, separating the subject from its background to give it more prominence making it much easier to keep the viewers’ attention. Or, to reduce an obtrusive background which can detract from the subject. In order to achieve this, we sometimes use large aperture lenses often shooting wide open to create this effect.
In the world of macro photography, it’s completely different. Depth of field is one of the biggest issues since photographing subject’s that are small means having to work at much closer distances. Retaining sharpness throughout the subject being photographed depends on two factors, magnification and the aperture value. Wider apertures produce less depth of field while smaller apertures allow us to retain more of the subject in focus up to a point depending on the magnification chosen. Even shooting at smaller apertures, for example, F/16 does not necessarily guarantee complete sharpness. There are also trade-offs for using smaller apertures diffraction being the most obvious one, which can cause a reduction in sharpness and detail.
Since the evolution of digital photography and advancements in software technology, it is now possible to overcome many of the problems often faced by macro photographers. Focus Stacking or Extended Depth of field is one of the advantages we have at our disposal. I should point out from the start that it is not the answer and solution in every single case. It largely depends on what you are trying to achieve. It is not always necessary to have complete sharpness in an image for several reasons. For example, you may want to create an artistic interpretation and the choice aperture is important. Also, mobile subjects such as insects present a greater challenge when employing focus stacking. Trying to capture multiple images of a moving creature brings its own frustrations.
Recently I have been testing and reviewing the Castel-Micro; a motorized focusing rail developed by Novoflex. There are many advantages to using a motorized rail, especially when working at higher magnifications. It can deliver great accuracy in controlled focus advancement and continuity in focus overlap producing images with fewer artefacts for software to correct. Another advantage is you do not have to touch the camera assembly during the process therefore reducing the risk of movement during the stack sequence. Photographing at magnifications beyond 1:1 opens up a whole new world of subjects that would be much more challenging to photograph at higher magnifications doing it manually.
The Castel-Micro in my opinion is an excellent product and takes much of the guesswork out of focus stacking. If you want to explore magnifications beyond life-size then using a motorized rail will make the process much easier. To read the full review of the Castel-Micro click here.
Below are some of the examples photographed with the Novoflex Castel-micro.
Thompson FRPS FIPF award winning natural history photographer, author, freelance writer, conservationist and entomologist. Specialising in macro, travel, aerial and conventional landscapes nature & wildlife photography. Frequent contributor to the photographic press and other natural history publications. Photography seminars, lectures workshops. Specialist interest in insects especially butterflies, moths, saturniidae, dragonflies, seashore, plants, orchids., fungi and lichens.