I was considering getting a 2x 7 Elements Teleconverter for my Nikon D5100 Camera. I was wondering if anyone has used them, and if so, what you thought. Any opinions would be appreciated. Thanks.

I havn't used that one in particular but i can tell you the 2X first party nikon significantly degrades the image quality of a pro level lens like the 70-200mm, I can't imagine how bad it would be on a consumer level lens. Plus you probably lose 2 stops of aperture so you might be shooting at F8, which means you can only use it on extremely sunny days

I knew about losing the two stops... I think I can deal with that. I'm just not really sure if it's worth the money. If 20 people said that it was awesome, and I just HAD to get one, I'd most likely do it. I think maybe I really wanted someone to talk me out of it... at least for now!

I have a Vivatar 2x because the Nikon's teleconvertor doesnt work with my 70 - 300 mm lens. Auto focus can sometimes be awkward and I manually focus with My Sigma 150 - 300. It cuts alot of light on the nikon lens but is not bad with the Sigma. I am happy with the quality of the image. I also manually focus with my 60 mm macro. If your looking to shoot quickly, I dont recommend it but if you have the time to precision your work then it is worthwhile. Good luck