Extension tubes are empty tubes we can attach between our lens and camera body to extend the lens farther from our film or image sensor. This lets us focus much more closely for macro use, but also reduces the effective exposure due to the extra distance.
Make sure the camera is wound i.e. the shutter is cocked and exposure signal is white. Make sure the extension tube shaft key is cocked before mounting a lens
Exposure Compensation Chart
| Lens | Extension | Exposure Compensation |
|---|---|---|
| 50mm | 16mm | 2/3rd |
| 50mm | 32mm | -1 stop |
| 80mm | 16mm | 2/3rd |
| 80mm | 32mm | 1 stop |
| 150mm | 16mm | 2/3rd |
| 150mm | 32mm | 1 stop |
| 150mm | 50mm | 4/3rd |
Portrait Composition
- 150mm : Head and Shoulder shot
- 150mm + 16mm Extension tube: Head shot
- 150mm + 32mm Extension tube: Face Closup
Minimum Focusing Distance
| Lens/Tube | 16mm | 32mm | 50mm |
|---|---|---|---|
| 50mm | 206mm | * | * |
| 80mm | 480mm | 280mm | 196mm |
| 150mm | 1.556m | 583mm | 559mm |
* doesn’t work; focuses so close that it focuses inside the lens!
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