The PRO 300 family are designed specifically to be used with prime telephoto lenses of 100mm or above, and work best with telephoto lenses of 200mm to 500mm.
The PRO 300 can be used with telephoto zoom lenses as well as prime lenses. However, Kenko does not recommend them for zoom lenses that have a range starting under 50 mm.
* Multicoated for high resolution
* 7 elements in 4 groups
* Length 43.5mm
* Weight 184g
* Full AF operation with Teleplus 2X Pro 300 is possible when using camera lenses with maximum aperture of F4.5 or faster
* Digital Compatible
* Exposure factor 2 stops