The Kenko 1.4x DGX 4

The Kenko 1.4x DGX is a pretty cheap alternative to the Canon version. So far I have no complaints about it. It's one of my most important accessories for taking outdoor shots. For around $120 it is a steal. It includes the front and end cap and a bag. Image quality is pretty good. I recommend it. But what basically is a teleconverter?

One of the most important tools that photographers use is the teleconverter. Teleconverters are basically extenders for your lenses. A 1.4x teleconverter means that it multiplies your range to 1.4 times. A 2.0x teleconverter doubles it. So a 200mm lens with a 1.4 teleconverter will become a 280mm, and it becomes a 400mm with a 2.0x. It is way cheaper to buy teleconverters than buying lenses with greater focal lengths, and also it allows you to still use your favorite lenses that you already have. So what's the catch?

Teleconverters slow down your lenses...you'd lose 1 stop with a 1.4x teleconverter and 2 stops with a 2.0x. So your f2.8 lens will be an f4 lens with a 1.4 teleconverter, and it will be an f5.6 with a 2.0 teleconverter. I opted to get a 1.4 instead of the 2.0 because 2 stops is a lot to lose in my opinion.

Teleconverters also have an effect in your lens focus speed. You need that extra focus speed when photographing flying birds or that tennis player that's running around in the court. I use a teleconverter for my 70-200 IS USM lens and considering it has a fast focus motor, I feel that the speed is greatly reduced when I use my teleconverter.

Another downside to using them is the image quality. Anything that you add on to your lens optically diminishes the quality of it, that extra glass will have an effect on the quality. Extension tubes though are different because they only increase the distance of your lens to your sensor and they don't have extra glass in them...they are just tubes. With teleconverters, expect more chromatic aberrations on your images. Also you can only use these on lenses that are 50mm and longer.

They are cheaper though than buying the actual lens with the same focal length. It's also lighter to bring than bringing that extra lens.

All in all, it's up to you if a teleconverter is worth it. I use it all the time for bird hunting.

Here are my sample shots with the teleconverter attached to my 70-200 lens: