Nikkor 400mm f/5.6 ED IF Ai-S

[David H. Hartman]

Something must be wrong, it should not be like this at all

It's inherent vice.

My first telephoto, a 300/4.5 Nikkor H (Pre AI 1973), exhibited the same behavior. As the helical is racked out the weight of the lens moves forward and less of the helical engages the other side so it binds. I bought this lens new, before the 300/4.5 ED-IF was released. The 300/4.5 ED-IF can be focused with one finger allowing more in focus shots.