I just got back from an amazing week photographing birds in the Texas Rio Grande Valley. Here, I had the opportunity to really test my Nikon D4 with the 600mm f/4 AFS G VRII Nikkor. I also brought all three of my teleconverters, the Nikon TC-14E, TC-17EII and TC-20EIII. Most of the time, I was perfectly happy using the 600mm lens alone, or with the TC-14E. However, I did get a few opportunities to see how well the TC-20EIIII would perform, and it was a winner.
Using the TC-20EIII teleconverter
The first thing to keep in mind with the TC-20EIII is that you’ll lose two full stops of light. Therefore, my 600mm f/4 lens became a 1200mm f/8 lens. With the new AF system in the Nikon D4, you can get good focus performance at this effective aperture. With the D3, AF is possible but less accurate, especially in dim conditions. The other thing to do when you work with these very long focal lengths is to use AF Fine Tuning to really dial in the focus. Even small focus errors will be noticeable at these magnifications, especially with birds. For a quick test, try focusing on a subject using Live View for a reference shot. Then defocus the lens and use the normal AF to take a second shot. If the Live View shot is sharper, it means that you’ll probably benefit from using AF Fine Tuning.
Once my settings were dialed in (I used +14 in this case), I was getting great shots wide-open with this combination! With any long lens, it’s a good idea to manually pre-focus the lens and then use the AF system to get the final focus lock. And as always, I used my “back button” AF-ON technique to get the best focus performance out of my camera.
Here’s a 100% (actual pixels) crop of the image.
I’m already planning to go back to South Texas again in 2013, so drop me a note if you’re interested in this one of a kind trip!