Teleconverter for Nikon D40X?

Question

I have a Nikon D40X with a Nikkor AF-S DX VR Zoom-Nikkor 18-200 f/3.-5.6G IF-ED lens. How would I benefit from, and how would I use a teleconverter? Which one?

My subject matter is usually birds.

Thanks.

Answer 1

Nikon offers 3 teleconverters:

1.4X

1.7X

2.0X

Using the 1.4X your lens becomes a 25.2-280mm zoom; your effective f-stop becomes f4.9-7.82

Using the 1.7X your lens becomes a 30.6-340 zoom; your effective f-stop becomes f5.95-9.52

Using the 2x your lens becomes a 36-400 zoom; your effective f-stop becomes f7.0-11.2

Yes, using a teleconverter affects your f-stop as well as your focal length. In all likelihood you'll have to use a higher ISO to compensate for the light loss from the teleconverter. Using a tripod is also recommended when possible.

Answer 2

There are pro's and cons to teleconverters, but they are mainly made to be used with fixed focus lenses, see a obvious plus would be that you could have a 400mm lens for the price of a converter and a 200mm lens, the downside is that depending of the magnification of the teleconverter you lose certain stops of light, you lose 1 stop for a 1.4x and 2 stops for a 2x which would mean your f/3.5-5.6 would turn into a f/5.6-8 with a 1.4x and a  with a 2x would turn into a f/8-11 that a major light loss, that would make your autofocus inoperable because most cameras need a minimum level of f/5.6 to be effective but even though you have a light loss you could technically just bump up your ISO and be fine.  The main thing you should keep in mind is that the teleconverter you buy will have to be specific to your lens, they like fixed focus, and to be honest I don't know if they make a converter for the lens you have, either way thats the ins and outs.