Answer
Apr 18, 2023 - 10:49 AM
The 2X teleconverters are great, but they take away 2 stops of light. Therefore, they would NOT be a good match with the 18-400mm f/3.5-6.3 lens because the converter would not autofocus well. The aperture would simply be too dark. We would suggest a Tamron 150-600mm lens if you need more telephoto length. They are available new, and sometime used, too! Please call our team @ 410-235-6200 to discuss your issue with an expert.
