What Is An Extension Tube ? Update 12/2021

extension tube

An extension tube has several advantages. Then, we’ll go over some of the most popular extension tube models to show you how they work and how to use them.

If you’re new to macro photography, a dedicated macro lens for your camera is a good place to start. Alternatively, use a macro extension tube in conjunction with a lens to get amazing results! Maximize the magnification of your lens by using extension tubes and macro lenses together.

1. What Is An Extension Tube ?

extension tube-1For a lens-to-camera conversion kit, an extension tube is a hollow tube that slides in between the two components. They enable you to zoom in on objects that are closer to the camera and focus on them more closely. This is why they’re also known as macro tubes: they allow you to take macro photos without the use of a special macro lens.

Extension tubes don’t have to be expensive because they don’t have any optical components. Add-ons (such as filters and teleconverters) can introduce new distortions. They’re also very adaptable, working with any lens and stacking multiple extension tubes.

2. How Extension Tubes Work

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Lenses direct light to the sensor at a specific distance. To project the focused image onto the sensor, every lens has a minimum focus distance. In the event that an object is positioned too close to the lens, the sensor will not be able to detect it.

An extension tube allows you to fine-tune the focal point by moving the lens away from the camera body. This enables you to get a better focus on objects that are in close proximity to the lens.

It does have one drawback, however, in that it brings your minimum focus distance closer to the lens in exchange. You will be unable to focus at infinity if you use an extension tube. You may only be able to focus on objects that are a few feet away with certain lens and extension tube combinations. In order to achieve the greatest magnification, extension tubes should only be used.

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Your lens and extension tube options will determine how much additional magnification you receive. If you want more magnification, divide the extension tube’s length by the focal length of the original lens.

Canon’s EF 50mm f/1.8 STM lens, for example, has a native maximum magnification of.21x. It’s possible to increase the magnification by.5x simply by using an extension tube of 25mm. With a 12mm and a 25mm extension tube, the total magnification will be.95x, which is very close to the magnification of a real macro lens.

An extension tube, then, has a greater impact on shorter lenses because of this. A 50mm lens with a 25mm extension tube has a.5x increase in magnification. A 100mm lens will get a.25x boost in magnification, while a 200mm lens will get.125x.

3. How To Use An Extension Tube

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If you want to use an extension tube, all you have to do is connect it between your camera body and lens. There are no more controls or mechanics to be concerned about once the extension tube and lens are in place.

In general, the more you zoom in on an image, the more susceptible it becomes to camera shake. If you’re going to use a longer focal length, you’ll also want to use a faster shutter speed and a tripod or flash to freeze any motion and get an accurate shot.

The aperture of your lens can be changed by using extension tubes. The focal length divided by the aperture’s pupil diameter is known as the f-stop. In this case, the f-stop is f/4.0 (100mm/25mm), since the aperture is 25mm in diameter. For the same aperture setting (25mm diameter), you’ll get an effective f-stop of f/6.0 with a 150mm focal length from an extension tube combination. As a result, the sensor will receive less light, and you’ll need to make adjustments to account for that.

When photographing with a macro lens and an extension tube, you must make the same adjustments. First and foremost, your field of focus will be extremely small if you use a close-up lens setting. The depth of focus is measured in millimeters at these focusing distances. If you want perfect focus, you’ll need to use smaller apertures, use manual focus (which is likely to be more reliable than autofocus), and possibly use focus stacking tricks.

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4. Pros And Cons To Using An Extension Tube

Using extension tubes has the benefit of being very cost-effective in comparison to other options. For a fraction of the cost of a dedicated macro lens, you can get all the benefits of macro photography without breaking the bank. Due to the fact that they don’t contain any actual optics, they don’t introduce any additional distortions like filters and teleconverters can. They’re very adaptable, working with any lens and stacking multiple extension tubes.

To begin with, extension tubes are incredibly light and small. Extending tubes with another lens saves space and weight when packing your camera bag instead of adding a dedicated macro lens.

It is possible to magnify problems already present when using extension tubes because distortions are not introduced. Even at their shortest focus distances, some lenses lack sharpness. You can magnify the issues you’re seeing by attaching an extension tube to one of these lenses.

Extension tubes have the drawback of increasing your minimum focusing distance while decreasing your maximum focusing distance at the same time.. You will be unable to focus at infinity if you use an extension tube. You may only be able to focus a few feet away with certain lens and extension tube combinations. In order to achieve the greatest magnification, extension tubes should only be used.

An extension tube changes your effective focal length and aperture, as well as increasing the f-stop number. You increase the likelihood of camera shake by essentially lengthening your lens. When you reduce the aperture’s pupil diameter, your f-stop decreases as well, resulting in less light hitting your sensor.

In this case, the f-stop is f/4.0 (100mm/25mm), since the aperture is 25mm in diameter. For the same aperture setting (25mm diameter), you’ll get an effective f-stop of f/6.0 with a 150mm focal length from an extension tube combination. Both of these effects must be taken into consideration and compensated for.

5. Types Of Extension Tubes

Because extension tubes are so basic, you can find them for dirt cheap. It’s important to remember that not all extension tubes are created equal.

Extension tubes may or may not work with your camera, depending on the make and model. If they’re not, you’ll be unable to use the camera’s aperture and autofocus functions. Non-electronic extension tubes will leave your lenses wide open if they don’t have manual aperture controls, making them difficult to use due to the small depth of focus you’ll have.

Both Canon and Nikon make extension tubes in a couple of different sizes:

Model Length
Canon EF 12 II 12mm
EF 25 II 25mm
Nikon PK-12 14mm
PK-13 27.5mm

 

Think about electronic aperture control and autofocus when choosing an extension tube. Extension tubes of lower cost may be the best option for your needs because optical performance is not affected by the presence of glass elements that could interfere with light transmission. Extension tubes aren’t currently made by other major lens manufacturers like Kenko, Vello, or Neewer, but there are a number of third parties that do.

In order to get a more durable extension tube, you will have to pay more. To avoid damaging the cheaper extension tubes, be extra careful when using them. Some cheap extension tubes, in particular, are known to have threads that get stuck to your lenses due to their weak construction. This lens can only be used for macro photography if the extension tube can be removed.

6. Choosing An Extension Tube

Camera mounts of all types can benefit from the use of extension tubes. Using an extension tube with a lens that has a different mount from your camera body is not recommended. Even if you don’t encounter any issues, using extension tubes and an adaptor at the same time does increase the number of possible points of failure.

Using a smaller aperture extension tube means you’ll need a camera that performs better in low light, so keep that in mind when choosing your gear. If your camera has trouble with higher ISO settings, you may have trouble getting your photos to be properly exposed.

If you’re going to use an extension tube, you’ll want a camera with a large enough sensor to give you a native crop of the image (and additional magnification).

Crop sensor cameras with excellent low-light performance will work the best with an extension tube, but any camera will work well with one.

Adding macro capabilities to non-macro lenses or increasing the magnification of your dedicated macro lenses is easy with extension tubes. Due to the extension tube’s simplicity, there isn’t much of a performance difference between different manufacturers’ products. Using an extension tube in conjunction with the appropriate lens can provide you with a plethora of new photographic opportunities.