I am considering in investing in the Sigma 2x teleconverter to try and get closer to some aircraft and possibly get some high altitude aircraft shots. I have a couple of questions. Firstly, I am using a Nikon D3100 with a Sigma 70-200 f2.8 so I was just wondering if the teleconverter is compatible with my lens and body? Secondly, because of a crop sensor my 70-200 is a 105-300 so does it double to 210-600? If so will that be long enough to get some contrail shots? Lastly, what are the pros and most importantly the cons of a teleconverter? Is a lot of light and quality lost?
Thanks in advance for everyones help