What is a teleconverter?

What is a teleconverter?

Hi and welcome to Cameras Direct.

This week’s video is on teleconverters (extenders).

A teleconverter is a device that fits between the lens and camera body. It is designed to increase the focal length of lenses that you already own. Because of this it is a cost-effective solution for many sports and wildlife photographers. Rather than purchasing lens is dedicated to this style of photography.

There products are manufactured for all types of lenses although they do the same thing they are referred to as different names. For instance Nikon does refer to them as teleconverters. Canon on the other hand refers to them as extenders. Third-party manufacturers go between a mix of these names.

So what do these teleconverters come in?
They are available in 1.4 x 1.7x 2.0x and 3.0x times conversion factors. The 1.7 is specifically a Nikon lens and 3 is not so common.

But what do these numbers mean?
The number assigned to each teleconverter is letting you know how much it is modifying your current lens.

Let’s take an example.  You currently have a 100mm lens,  and introduce a 1.4 teleconverter. Effectively you are now shooting at a focal length of 140mm. This might sound like a great option how there are compromises you have to consider.

Because you’re introducing more optical elements between the lens and the camera body, light traveling towards the sensor is dispersed. Inherently you are going to end up with a loss in quality of your image.

The second thing to consider is loss of light. Because we’re increasing the distance between the lens and the camera body, light has to travel further. In a 1.4 teleconverter, this amounts to one stop of light. In a 2x converter, two stops.

So let’s put this into practice.
Let’s use the example of the 100mm lens and introduce a 1.4 converter.
If we shooting at f/2.8 originally the introduction of this teleconverter remains that we are now shooting at a focal length of 140mm, and a f stop of f/4. Now let’s use at 2.0 times converter. We have effectively increased our focal length to 200mm. Although we have lost 2 stops of light resulting in shooting at an f stop of 5.6.

Before you rush out there is one last thing we have to check. Compatibility. For most lenses over 100mm and and an f stop of 2.8 or F4 are best going to work with teleconverters.

For a full list check at the Description box in his video.

It is also important to remember the larger the teleconverter you use, the more likely you are to decrease the quality of your image.

That wraps up our talk on Teleconverters.

Thanks for watching and happy shooting.

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