How to Convert a Lens to Telephoto

Photography is all about the lenses. They are the eyes of the camera and the way that light gets onto the recording medium whether that is film or a digital sensor.

What is a Conversion Lens?

The biggest advantage that DSLRs have over many competitors is the massive ecosystem of lenses that they inherited from their 35 mm ancestors. The interchangeable lens model offers a range of capabilities that's hard to beat. Unfortunately, not all cameras can switch lenses, and that's especially true of camcorders. However, there is a way around that; namely you can use an auxiliary conversion lens. There are two types of conversion lenses:

  • Telephoto Lenses: These lenses mount directly on top of the existing lens and give you a little more zoom than you would otherwise have. Do note that they are fixed lenses and do not provide variable magnification.
  • Wide Angle Lenses: Wide angle or macro lenses give you a wider field of view so that you can get more area into your frame.

How Do You Choose a Telephoto Conversion?

One place where you can use a conversion is on a camcorder. Unlike cameras, they generally do not have interchangeable optics, but rather use a single lens for all purposes. While the zoom is usually pretty good, sometimes you want a little more, which is where a conversion can come in handy. It gives you a little more flexibility without the requirement of maintaining interchangeable lenses. There are two aspects to consider:

  • Attachment: Many camcorders have a 37 mm thread system for attaching a filter. By designing a telephoto adapter for the same filter size, you can replace a 37 mm filter with a telephoto as soon as you remove the lens cap.
  • Functionality: Because conversions offer a fixed focal length, you need to decide how much zoom you want when picking camera lenses. They often offer anything from 2.0x Optical zoom to 4.0x; which adds to the camcorder's existing zoom functionality.

Using Conversions

Just like any other photo accessories, using an auxiliary conversion lens isn't difficult so long as you understand what you're doing. One thing you do have to remember is that when you attach the telephoto it sets both a new minimum and a new maximum zoom for your camcorder. No matter what you do, you can't step down below the rating of your new lens as the focal length won't get any shorter until you remove the zoom lens. Also remember that the more you magnify an image, the more important stability becomes. This is why a tripod can be so helpful; it gives that additional stability you need for a clear shot at any magnification.