What is the difference between AF 80-200/2.8 D ED IF and a the same with a AFS other than price? They both auto focus, but what is the difference?

-- George p. Smerlis (GPSDDS@worldnet.att.net), December 02, 2000

Answers

George,

I think there's a very minor difference between the lens formula of these lenses. I know from practical experience, the 80-200 AF-S is outstanding. There are many reviews of the super high quality of this lens.

Probably the most important difference between lenses is the auto-focus mechanism. The ED-IF auto-focus is powered by the camera's internal motor. The AF-S lens is powered by its own internal motor. The essential point is the AF-S is significantly faster than its counter part. In fact this particular lens may be the fastest that Nikon offers.

Cheers

-- Tom Hill (teamhill@f15.net), December 02, 2000.

The "S" stands for the "Silent Wave" focusing motors that are built into the lens. It's about like Canon USM (UltraSonic Motor) or Sigma's HSM (HyperSonic Motor).

I'm no Nikon expert, but as I recall the AFS lenses will do fast, silent AF with instant manual override, just like Canon's FTM (Full Time Manual focusing). I don't know about all of Nikon's AFS lenses but not all of Sigma's HSM's will do FTM. I do know that AFS will only work on newer Nikon bodies.

-- Jim Strutz (jimstrutz@juno.com), December 02, 2000.

Actually, the optical construnction of the two lens are totally different. The AF-s lens is a true internal focus, internal zoom design. The front and rear lens groups on that lens remain fixed when focusing and zooming. The effective focal length changes quite a bit when the focus is changed. The older AF lens moves the front lens group focus and zoom, but seem to hold the same focal length when focusing.

In practice, the new AF-S lens is somewhat faster in focus, marginally better wideopen, but most importantly, tracks moving objects much more smoothly. It also allows manual focus override at anytime without the need to switch the M/A collar on the lens.

-- Chuck Fan (chaohui@msn.com), December 03, 2000.

Jim is right. all AF-S lenses (8 at the last count) permits full-time manual focus override. However, Nikon FT-M uses a clutch that fixes the manual focus ring at the moment when AF motor is actually turning. The clutch releases the manual focus ring when the AF motor is stopped. The Canon FT-M lenses uses a different (IMHO more elegant) solution that employes a planetary gear like mechanism without any clutch. In most Canon FT-M lenses, the focus ring can be turned when AF motor is turning. In practice, it is probably not recommended that you tinker with the focus when AF motor is turning. So this different would probably be of little consequence.

-- Chuck Fan (chaohui@msn.com), December 03, 2000.