Macrophoto Group Auto Extension Tubes 7/14/25
|Notes - Related Units
|These tubes are used as adapters to mount OM System lenses on the OM body
to take close-ups.
Each tube incorporates a coupling lever to automatically stop down the lens diaphragm to the preset aperture at the exposure.
|The respective lengths of these tubes are 7mm, 14mm and 25mm, which make
seven different lengths by single or combined uses.
They can be mounted on the camera body by bayonet mounting as in case with the standard lenses.
If all of these tubes are used in conjunction with the 50mm F1.8, it is possible to achieve a life size magnification or 2.3x3.4cm with a lens-to-subject distance of 6.8cm.
The 25mm extension tube can be used to extend the magnification range of the Zuiko Macro Lens 50mm to 1:2 and 1:1 (lifesize).
For life-size pictures, however, most recommended is the 1:1 Macro 80mm F4.
|The depth of field is extremely small in close-up work. Therefore, not
only correct focus but also a small aperture such as F8 or F11 are recommended.
Even a smallest movement of the camera affects pictures especially when enlarged to great extent. To avoid this, make it a point to use a focusing stage, tripod and cable release whenever available.
Table of close-up ranges
Hatched area indicates magnification ranges of standard lenses without close-up lens.
Numbers printed at both ends of each arrow indicate distances in cm (inches) between lens and subject.