What teleconverter fits the Nikon D40?

Looking for a teleconverter for my Nikon D40. Which ones will work for it?

To answer this question we also have to know what lens(es) you plan on using it with.

Your mention of the D40 indicates that you probably want something that'll preserve auto-focus and metering with AF-S lenses. That makes Nikon's current TCs your best bet, but these are only compatible with high end Nikon tele lenses… Which would be an odd combination on a D40.

I checked your earlier questions… If you went with the Sigma 150-500mm, you can use Sigma and Kenko TCs: http://www.birdforum.net/showthread.php?t=196713

Or simply Google: D40 TC 'Your lens'

From personal experience, I'm happy enough with the performance of my Kenko Pro 1.4x TC, which I purchased instead of a Nikon TC because it preserves auto-focus with my 80-200mm f/2.8 AF-D lens. Had I splurged on a Nikon 70-200mm AF-S instead, I would have gotten a (fully compatible) Nikon TC to go with it.