1.4 teleconverter question

I have a Sony Alpha 100 and use a Sigma 50-500 zoom. Would I benefit by using a 1.4 teleconverter. I am thinking of purchasing one.
I photograph mostly birds here in SW Florida.

Thanks for your input,
John

I'm sorry, it is f/4-f/6.3

I'm not familiar with your camera and lens, in order not to lose AF, make sure that your camera can still autofocus with TC attached. If the Sigma is a 5.6 I would assume that the camera would not autofocus at f/8 and your only choice would be a non-reporting TC and the focus accuracy might drop significantly.

The Sigma 50-500's image quality suffers a lot with the addition of the 1.4X
It takes stellar technique to pull it off.

The Sigma is f/6.3 wide open at 500mm and with a 1.4x, I think it's unlikely to AF for you (although I'm not familiar with that body).