Oh got it. There was an awful lot of discussion a while back where Panasonic was providing different responses to the 50-200 and the TC. In some cases users were told they are a match, and in other they were told the TC was for the 200 f/4 only. My experience is that it can be cropped to 280 with very nice results anyway, so why spend the $?
I got into wildlife and the more I was shooting from distance the more reach I was wanting, especially for small subjects like birds. Foxes have a dependable habit of running away from me as fast as possible if I am to close, after finding a few times baby foxes I felt the want the reach even more. I haven't found any functionality loss with the TC, the sharpness is acceptable (though no one should expect to the level of Olympus 300mm f 4 Pro), the chromatic aberrations, coma, and astigmatism are well controlled, the OIS loses about 1/2 stop of effectiveness but still handles well up to 1/20 sec, the only thing I have noticed to be reduced is the AF speed in low light. Unless its bright or direct light the AF speed can come down to hunting from infinity and MFD for more then a second, even if the contrast is there (ex: I had a Robin with a pretty strong orange chest sitting on a branch with no leaves anywhere near it with a distinct green background from the chest and the lens would hunt through the entire range 3 times until it settled about 2 inches in front of the bird. The bird was about 60% of the entire frame, the AF was in AF-S with Single Centre Box (not the smallest one because then it uses only PD-AF instead of the CD-AF as well) and the light level was 1/25 sec. at ISO 6.400 and f 5.6. The failure was repetitive every time I tried for about 3 minutes before giving up.
Alternative options were :
*Panasonic 100-300mm f 4.5-5.6 Mark II - Not worth it on the overlap of FL,
*Panasonic Leica 100-400mm f 4-6.3 - Very specialized lens but the existence of Olympus 150-400mm f 4.5 Pro kept me from getting committed (plus the scraping mount with E-M1s),
*Olympus 100-400mm f 5-6.3 - It was not launched yet or had most of the specifications detailed,
*Olympus 75-300mm f 4.5-5.7 Mark II - Not weather sealed (a very important requirement given the UK weather) and I still have a bad taste left from the last time I used Olympus 14-150mm f 4-5.6 Mark II.
The Panasonic DMW-TC14 is not that much of an expensive try, it keeps the versatility of the 50-200mm f 2.8-4 lens, and best of all the price of the Teleconverter seems to hold up better than most Micro Four Thrids lenses.
