Nikon body cap: BF-3A vs BF-1A

Did you know that the front Nikon teleconverter cap (BF-3A) is not the same as the Nikon body cap (BF-1A). It is deeper! It (BF-3A) can act as the body cap but not vice versa. That is, BF-1A doesn't fit Nikon teleconverter. It is because the front element of Nikon teleconverter (1.4x, 1.7x and 2.0x) protrudes out at the front. The good thing is that the front element is a concave lens hence if you try fitting a BF-1A on a Nikon teleconverter, it won't scratch it. To set the two front caps apart, BF-3A is grey colour while BF-1A is the usual black colour.

From now on, if I need a spare or replace a Nikon body cap, I will go straight to a BF-3A. Be careful, most ebayer only sells BF-1A, the normal black front cap.