Thanks for the comments guy's
I use a Nikon D300 dSLR and a Nikon 300mm f2.8 prime lens. If I need a little extra reach I use a x1.4 teleconverter which turns the 300mm f2.8 lens in to a 420mm f4. I always use auto focus.
All shots taken from Cad West which is part of the Mach Loop. This is located just south of Dolgellau, Mid Wales. I've more info on my site
www.rcflights.co.uk
Cheers,
Mark