Extension tubes are accessories used in photography to enable close-up and macro photography with interchangeable lens cameras. They are hollow, cylindrical tubes that fit between the camera body and the camera lens. Extension tubes are designed to increase the distance between the camera's image sensor and the lens's rear element, which allows for a closer focusing distance and the ability to capture highly magnified images of small subjects, like insects, flowers, or other intricate details.
Here's how extension tubes work and how to use them effectively:
1. Understanding the Basics:
Extension tubes do not have glass elements or optical components of their own. They simply create additional space between the lens and the camera's image sensor, altering the lens's minimum focusing distance. The longer the extension tube, the closer you can focus on your subject and the greater the magnification you can achieve.
2. Compatibility:
Extension tubes are available in various sizes and mounts to match the camera's mount and lens type. Ensure you choose extension tubes that are compatible with your camera system and lenses.
Extension tubes are typically sold in sets, often including different tube lengths that can be combined for various levels of magnification.
3. How to Use Extension Tubes:
Mount the extension tube(s) between your camera body and your lens.
Turn on your camera and lens, and set the lens to manual focus (MF) mode.
Adjust the distance between the camera and the subject by moving the camera forward or backward until your subject comes into focus.
Fine-tune focus by manually adjusting the focus ring on the lens.
Use a tripod or other stabilizing equipment to minimize camera shake, as close-up photography can be especially sensitive to movement.
4. Aperture and Exposure:
When using extension tubes, your lens's aperture may not work as usual. In most cases, the aperture will remain wide open (at its maximum) because the extension tubes do not transfer aperture information from the camera to the lens.
You will need to adjust exposure by either using manual exposure settings or by using the camera's exposure compensation feature.
It's advisable to use a small aperture (higher f-stop number) to increase depth of field and maintain focus on the subject.
5. Lighting:
Macro and close-up photography often require controlled lighting to illuminate the subject properly. You can use external flashes, ring lights, or diffusers to achieve even and flattering lighting on your subject.
6. Depth of Field:
Close-up photography with extension tubes results in very shallow depth of field. Be mindful of this and choose your focus point carefully to emphasize the most critical parts of your subject.
7. Practice and Patience:
Macro and close-up photography can be challenging due to the precision required and the shallow depth of field. Practice and experimentation are key to achieving desired results.
Extension tubes are valuable tools for photographers looking to explore the world of close-up and macro photography without investing in expensive macro lenses. With the right extension tubes and some practice, you can capture stunning and highly detailed images of small subjects.