With the speed of the Camera, you should be fine, but if I were you, I might reconsider the lens length! 400 mm lenses are hard to handle, subject to camera movement, and will require a shutter speed of up to 1/2000th second to prevent camera blur! Remember, the equivalent length of that lens is about 600mm compared to film cameras, and hand held, I doubt you will be successful! You would probably prefer a lens, say 18-105 mm for general shooting for your trip...consider it, at any rate. I take back the 1st sentence...in greatly subdued lighting, and at shutter speeds you will have to work with (unless you are taking a tripod), you may not have a big enough lens....think this through carefully before committing to that lens. I cannot imagine why you would need a telephoto lens in a rain forest, where vastness of picture is often more important than tiny parts of the total picture. IF your lighting requires F 5.6, Iso 100, 1/60th second, you do not have the headroom in shutter speed and ISO to take successful pics!
With the above conditions, you would only be able to go to 1/500th second at ISO 1600 !!!!! Ask the pro here, Fhotoace in email and see what he has to say..cut and paste my reply and see if he agrees. I bow to his experience. Happy Holidays
