I've always been under the impression that teleconverters reduce image quality. My first teleconverter was a 4-element Vivitar, which I used with my Canon FD lenses, and it really did reduce image quality, especially if shot with the lens wide open. Many years later, I tried a Kenko Pro teleconverter with 7 optical elements. It was much better than the Vivitar, but I would still get a lot of chromatic aberration when I used it my 300mm f/4 Nikkor (having switched to Nikon at some point.) That experience led me to put away the TC and pretty much forget that I owned it.

Recently I have been doing a lot of bird photography, which generally requires long telephoto lenses -- the longer, the better. I started using a 200-500mm Nikon zoom, which is a fine lens, but even 500mm is too short for a lot of bird photography. The 200-500 has a couple of features -- vibration reduction and electronic diaphragm control -- that didn't exist back when by teleconverter was made. I started wondering whether the lens would work with the TC, and to my surprise, it did!

The 200-500mm Nikkor has 19 lens elements, and I felt that adding 7 more would not be conducive to high image quality, but to my surprise, image degradation has been less noticeable than I expected. I have only been using the combination for a few days, but I have been pleasantly surprised by the results I'm getting. The 200-500 isn't the best-handling lens -- it's heavy and bulky -- but the TC adds less than an inch of length and only 5 or 6 ounces of weight. It makes the lens into a 280-700mm zoom with a constant aperture of f/8, and the 700mm focal length is letting me get shots that just wouldn't work at 500mm. I'm also not having any trouble with focus speed or accuracy at f/8, even using the off-center AF points of my Nikon D7100.

I never thought I'd be using a teleconverter with a long zoom lens (particularly such an old teleconverter!), but my results have been surprisingly good, and having 700mm at my disposal surely helps!

I've always been under the impression that teleconverters reduce image quality. My first teleconverter was a 4-element Vivitar, which I used with my Canon FD lenses, and it really did reduce image quality, especially if shot with the lens wide open. Many years later, I tried a Kenko Pro teleconverter with 7 optical elements. It was much better than the Vivitar, but I would still get a lot of chromatic aberration when I used it my 300mm f/4 Nikkor (having switched to Nikon at some point.) That experience led me to put away the TC and pretty much forget that I owned it.

Recently I have been doing a lot of bird photography, which generally requires long telephoto lenses -- the longer, the better. I started using a 200-500mm Nikon zoom, which is a fine lens, but even 500mm is too short for a lot of bird photography. The 200-500 has a couple of features -- vibration reduction and electronic diaphragm control -- that didn't exist back when by teleconverter was made. I started wondering whether the lens would work with the TC, and to my surprise, it did!

The 200-500mm Nikkor has 19 lens elements, and I felt that adding 7 more would not be conducive to high image quality, but to my surprise, image degradation has been less noticeable than I expected. I have only been using the combination for a few days, but I have been pleasantly surprised by the results I'm getting. The 200-500 isn't the best-handling lens -- it's heavy and bulky -- but the TC adds less than an inch of length and only 5 or 6 ounces of weight. It makes the lens into a 280-700mm zoom with a constant aperture of f/8, and the 700mm focal length is letting me get shots that just wouldn't work at 500mm. I'm also not having any trouble with focus speed or accuracy at f/8, even using the off-center AF points of my Nikon D7100.

I never thought I'd be using a teleconverter with a long zoom lens (particularly such an old teleconverter!), but my results have been surprisingly good, and having 700mm at my disposal surely helps!