Is there any 2x converters for Tamron AF 70-300mm f/4.0-5.6 Di LD?

I'm an entry level photographer, I wanna go to buy Tamron AF 70-300mm f/4.0-5.6 Di LD for my Nikon D3100. This is cheaper in cost. I need more zoom with that lens so I need 2x or 4x converter. Please about that staff.

What you need to know:

1) the teleconverters come in 1.4x, 1.7x and 2x
2) they are only successful if the widest aperture of f/2.8 or f/4

Until you are successfully producing amazing images each time you press the shutter release, you may want to wait before spending money on any lenses. After about a year or so, you will know if you want to spend money on a super wide angle or long telephoto lens.

A 2x teleconverter will lose two stops of light. With your lens, at 300mm it is 5.6, so losing 2 stops of light will make it an f/11 lens. You camera generally will not autofocus with an f/11 lens, so you are going to have to be really good about manual focus and since the lens is so slow, you are going to have to be super steady.

Just get closer to the subject or spend the money (huge $) to get a 600mm prime lens.