When you need to get up close, close-up lenses help. Ira Tiffen explains how close-up lenses and diopters work and how to use them for sharp detail shots.
Lenses are a marvel of light control. They manage to take in the many details of the world around us, and then, project them onto a recording surface for our subsequent viewing pleasure. You can use them to define what your audience sees and what they don’t see: viewing angle, depth-of-field, exposure, and much more are all managed by the exotic embodiment of optics extending outward from the front of your camera.
As capable as they can be, there will be times when they can use an assist. Filters, as we know, represent an array of assistant options that employ flat optical elements. However, even with their vast range, they can’t do everything. And one of those things they can’t do is help the lens to focus more closely than it was originally designed for. When getting closer is important, you need a close-up lens attachment. To better relate to the ability of close-up lenses to add interest to your images, it might help to think of Sherlock Holmes… his deerstalker cap, the clay pipe, the ever-present magnifying glass, “Aha, Watson, it’s elementary!” You can see what you’d otherwise miss when using a close-up lens, which is really a magnifying glass for your camera lens.
There are different styles of close-up lenses, although the basic one is analogous to the magnifier of Holmes’ choice: a single-element lens, with at least one side convex, and of positive diopter strength. A typical example would fit within the range of +1 to +5 diopters, where ‘diopter’ is a unit of measurement relating to the optical strength of the lens. I won’t get more detailed here, because it’s rare that you need to know more. There are tables and figures and equations readily available if you need them. Just be aware that a +4 is stronger than a +2; they can be combined for added strength; while they get you up close, they also reduce depth-of-field to what may be a very narrow range. And they’ll readily make a small object the center of your audience’s attention.
Other types of close-up lenses improve the image quality by adding more optical elements, with a generally concurrent addition to cost. Dual-element achromats have such enhanced qualities and are what you’d seek if the standard single-element lens isn’t right for you. Best way to tell is to test the single-element types first, as they are usually more readily available and more budget-friendly; if not acceptable, then go achro.
In our example images, the snail seems just another part of the landscape without the use of a close-up lens, taken at the closest distance to the subject that the un-aided camera lens will focus at.
Add the close-up lens, in this case a single-element +3 diopter, and you bring our snail to center stage – his presence is more powerful, for a snail, and this will allow you to tell his story with much greater effect than otherwise, without the lens attachment.
We all know of the many successful conclusions that Sherlock Holmes was able to deduce with the aid of his trusty magnifier. You’ll find close-up lenses can work their imaging magic for you, too.
In over 30 years of making optical filters, Ira Tiffen created the Pro-Mist, Soft/FX, Ultra Contrast, GlimmerGlass, and others, netting him both a Technical Achievement Award from the Academy of Motion Picture Arts and Sciences and a PrimeTime Emmy Award. Elected a Fellow of the SMPTE in 2002, he is also an Associate member of the ASC, and the author of the filter section of the American Cinematographer Manual.
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