Supplementary close up lenses

Photography at close range is possible with just a camera and its normal lens. Focusing down to between 46 and 61cm, a normal lens can easily produce frame filling close ups of subjects the size of a typewritten page without help. This capability although modest, is adequate for most of the copy work you may want to do. However, if you require tighter close ups, you will need accessory equipment of some kind.

The least expensive accessory is a supplementary close up lens. This single, positive glass elements screws onto the front of a lens mount like a filter and shortens the focal length of a prime lens, allowing you to focus closer than possible with the prime lens alone. In addition, unlike other close up equipment, an accessory close up lens requires no increase in exposure.

Supplementary lenses come in several different strengths or powers from +1 to +10. As the numbers get larger, focal lengths shorten, camera to subject distance shrink and images increase in size. Any tow powers may be combined to produce a greater power (+2 and +3 to make a +5, for example), but the results may not be as sharp as a single power used alone. Combining more than two powers at a time is not recommended. Sharpness may be further impaired, and light may be blocked off at the corners of the frame.

On inconvenience with supplementary lenses is that each power (single or in combination) permits focusing within a narrow range of distance only. Therefore, it might take several of these attachments to meet your entire close up needs. However, even then switching them around to obtain the right distance and the desired field of view is annoying and time consuming. If you plan to do a greater deal of close up work at various distances, you may want to invest in a variable focus close up lens. it is a more complex and more expensive accessory that lets you change powers (within limits) without changing supplementary lenses. However, for most photographers one or two single element attachments (+3 and +4) being the most useful) are all they will ever need.

Always install a close up attachments so that the convex (bowed out) side or the little arrow sometimes engraved on the metal rim, is pointed toward the subject. If a filter is needed along with a close up lens, put the filter on last. However, with the strongest powers the outward lens curvature may be so pronounced that the filter will have to go on first.

A close up attachment can be used with almost any camera and any focal length lens. if your camera has ground glass focusing, you will be able to see the field of view and point of sharpest focus easily. But if you have a fixed focus or rangefinder camera, you will have to measure carefully and adjust the distance between lens and subject according to the accompanying table, or those provided with accessory lenses.

With supplementary close up lenses overall sharpness is not as great as that produced using more sophisticated equipment. However, if the prime lens is stopped down at least halfway, results are adequate for many purposes. Small stops also increase depth of field, which is always very shallow in close up work.


More about close up lenses

- extension tubes
- bellow lenses
- macro lenses
- hints for close up photography
- tips for using close up magnification