Close focus dilemma (1 Viewer)

I currently have a Canon 300 f4 lens (used with 1.4x teleconverter), and I'm considering upgrading to the Canon 400 f4 DO IS ii. My subjects are usually birds and mammals in the interior of humid tropical forests. However, I've recently started to get more into herps, and I'm concerned about the loss of close focus (1.5 meters for the 300 f4, 3.3 meters for the 400 f4). How do people with prime lenses deal with this? Do you carry two lenses and switch in the field, or do you just get further away from the subject?

I would opt for a small extension tube if it would work.

My 800mm has a minimum focus distance of 6 meters - it can be a problem! Nikonmike suggests extention tubes will help.

Don't be fooled by expensive ones they are just tubes. Make sure you buy ones that allow AF and aperture control. I have two sets (one for each bag), the expensive (but stronger) ones were £13 for a set of three different length tubes.