Extension tubes are a great way to get closer to your subjects without actually getting closer to your subjects. In other words, they can make it seem like you are closer than you are. The extension tube goes between your camera and your lens, physically getting your lens closer to the subject you are shooting. But can you use autofocus with extension tubes?
Autofocus works with the extension tubes that have electrical connections to keep the continuity of your camera’s settings. This means you can still use any of the camera’s settings, including autofocus. But when you use the extension tubes without electrical nodes, you do not get that benefit.
The extension tubes without electrical connections are just plastic tubes that extend your lens further out from your camera. These are less expensive but do not let you utilize any of the settings on your camera. Let’s look at the two kinds of extension tubes.
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Extension Tubes Are Different
One thing to note about extension tubes is that they are not like converters or filters in that they do not have any glass optics in them. They are hollow tubes that just increase the distance from your camera sensor to your lens.
There are no added optical effects besides the length of your lens. The extension just increases the magnification.
Extension Tubes without Electrical Connections
The less expensive extension tube does not have any electrical nodes in it, so you do not get the benefits of the auto control or aperture settings on your camera. You will have to focus on the subject manually to get the best shot using the manual ring on your camera lens.
On the other hand, if your camera does not allow you to manually set the aperture, your camera will automatically be set at the highest aperture. You will have to stop down to get that sharpness you need.
These are really just hollow tubes that extend the distance between the camera body and subject.
Extension Tubes with Electrical Connections
For a bit more money, you can get an extension tube that has the electrical connections, so you are able to use autofocus and other settings. The electrical nodes allow your camera and the tube to communicate so you can use whichever settings you need.
Besides the autofocus, there are other concerns when using an extension tube, even with electrical nodes. Even if the autofocus works, the aperture will be different because of the loss of light that extension gives you. That means you will have to set the aperture or F-Stop yourself.
Extension Tubes Cause Loss of Light
One of the disadvantages of using an extension tube is that you will likely experience some light loss. The extension tube increases the aperture of the camera lens, so you will need to use a higher ISO or longer shutter speed to make up for the light loss. But if your camera is set to auto exposure, it will do all that for you.
However, many professionals find that the most effective way to use an extension tube is by setting your lens to manual focus anyway. With the manual focus ring on your camera, you can focus on the subject as needed, and your subject shows up extra-large in the viewfinder.
Autofocus Versus Manual Focusing
Autofocus is a fantastic addition to cameras. You can set your camera to autofocus and get an amazing shot no matter what you are shooting. You do not have to switch ISO or aperture between shots. But if you are using an extension tube without electrical connectors, you do not have that option anymore.
The narrow depth of field with close-up shots means that you have to have an incredibly steady hand and have to be extremely still. But using manual focus and a tripod with close-ups will typically give you a better shot than autofocus.
- Action Shots
If you are taking pictures of moving subjects like animals in flight or race cars, manual focus is the way to go. Autofocus just has a difficult time keeping up.
- Busy Backgrounds
Another type of shot you’ll need to use manual focus for is framed shots with busy backgrounds or foregrounds. Sometimes your autofocus wants to focus on the wrong thing. For example, if you have ever tried to take a picture of something through a fence, you probably needed that manual focus to get your camera to ignore the fence.
- Night Photos
In low light settings, you may need that manual focus advantage. For example, manual focus is better for outdoor night photos. Many autofocus cameras do not do well in low-light situations. Using the camera’s manual focus gives you the advantage of getting the light and contrast levels perfect.
Check Out the Histogram Setting
Many newer cameras may not let you set the aperture value because they are set to be automatically adjusted. The older ones will allow you to adjust the aperture so you can focus better on your subject for the best shot. No autofocus is needed for these situations.
If you are having trouble with this, try reviewing your LCD screen image after taking the shot. Look at the image with the histogram setting. That is the graph that allows you to see the distribution of the tones in your image based on exposure. It will help you figure out if you need to adjust the exposure setting.
If you are still having trouble focusing with the extension tube, try using a tripod. The heaviness of the extension ring may be causing a blur at slow shutter speeds. Even an ounce can make a difference when taking a photo at an extremely slow shutter speed.
You Can Use More Than One
Extension tubes also come in different sizes. Depending on the manufacturer, you can usually find them in sizes between 7 and 35 millimeters. The magnification that you get from the extension tube depends on its length.
The tube will increase the magnification by the amount equal to the extension distance divided by the lens photo length. Say, for instance, you have a 50-millimeter lens, and you add a 25-millimeter extension tube. That gives you a magnification increase of 0.5 times. But you can also use more than one tube.
Stacking extension tubes is easy and can get you an even better close-up photo of your subject. You can add as many extensions as you want. But remember, they add weight and affect balance. The more tubes you use, the harder it is to focus by hand. You will need a tripod if you use more than one.
The Pros and Cons of Extension Tubes
There are many pros and cons of using extension tubes compared to not using anything at all or comparing it to macro lenses. It also depends on whether you are using the extension tubes with electrical connections. Here are some of the basic pros and cons.
Pros of Extension Tubes
- Extension tubes are interchangeable with almost any camera lens.
- Extension tubes are much less expensive than macro lenses.
- The extension tubes are lighter because they have no glass.
- The loss of quality is minimal because there is no glass.
- The other benefit of no glass is that you do not have to worry about the degradation of the glass.
- They get you closer to the subject without having to get physically closer.
- You can stack the tubes to get a higher magnification.
- You do not lose pixels by cropping.
Cons of Extension Tubes
- If you get the extension tubes without electrical nodes, you cannot use autofocus.
- It can cause some vignetting in wider shots or those with higher stacks.
- The extra length and weight can mean you need to use a tripod for a steady shot.
- With the autofocus, you will still lose some light and have to use a higher aperture.
- You do not get much magnification with a telephoto lens.
- You need to use a longer shutter speed or higher ISO.
- Your lens will not be able to focus to infinity anymore.
There you have it. Autofocus can work with extension tubes and you are encouraged to experiment. Check out the histogram setting, as well as trying more than one extension tube.
And while you are at it, check out whether you would yield lower quality images while shooting with extension tubes.