Hi Folks -

Does anyone have experience with crazylong telephoto lenses, such as this:

http://www.bhphotovideo.com/c/product/8197…

I would imagine that for $100, one doesn't get great glass. I remember years ago seeing lenses like these in the Sears catalog - the lenses looked so long and cheap, it looked like they could buckle in the middle under their own weight... Do these have a purpose other than taking [supposedly] crappy pictures from way far away? Or are these some sort of best-kept secret and are actually pretty good?