Yes.

来源: 于 2007-01-13 18:23:28 [旧帖] [给我悄悄话] 本文已被阅读：次

There is no free lunch.

1. The lens image quality will decrease.

2. The f # will increase. For example, if you have a lens with f/2.8 and you use a 2x teleconverter on it, it will become a f/5.8 lens.