The constant f/4.5 apeture across the zoom range is welcome but it's slow - and at these apetures we expect ok-ish performance even wide open: its not bad but it doesn't seem outstanding and I'm quite sure the 18-55mm kit lens at the same apeture is better in terms of saturation, contrast and maybe sharpness. That's not to say it won't produce good images but for me there's no real captivating reason for huntinng this for your kit, but this is of course caveated by the late 1970s optical design - with that said, there are many legacy designs that are still hugely impressive: for example the Nikkor 28mm f/2.8 AI-S or the Nikkor 180mm f/2.ED 8 AI-S lenses. When comparing the 80-200mm to a modern kit lens, which modern lenses are truely bad at f/5.6 or f/8 nowadays? Many others have reported great sharpness and success with the lens.
The Nikon marketing materials make the claim that once in focus, always in focus implying that this is a parafocal lens - using the lens, I found the 3-4 samples I had were not quite live up to the claim with a small focus adjustment once focus was acheived and the zoom racked from 80mm to 200mm. I also noted that when I had serviced the lens, and one of the zoom/floating elements were not re-seated correctly, it resulted in significant focus shift when zooming and similar to some other experiences - whether brand new/from factory/super tight tollerance adjustment would give us true parafocus is to be seen.
Zoom creep (zoom changing when lens pointed up/down) is unavoidable - the way the zoom focal length was controlled was via a ring of felt at the front end of the focus ring, which obviously worn down over the last 40 years although its mentioned this was a problem very early on in lens ownership. Trying to replace/replicate the correct friction fit of the original is mostly a wasted effort - using gaffers tape or electrical tape is also not satisfactory.
The following images were at f/4.5 unless stated otherwise:
Sharpness
f/5.6 @ 80mm
centre crop f/4.5 @ 80mm
Misc Samples
Focus at infinity is reasonable at 80mm - this makes its quite nice for architectural details.
Backlit scenes comes with a reduction of contrast but surprisingly its holds up reasonable well.
A sequence of full zoom range:
Servicing
As with many lenses from this area (its been 40+ years!) maintanence or servicing is likely to be required.Lens Elements
The lens is fairly simple construction with access to lens elements reasonlably straight forward except for perhaps the middle element.
Nikkor 80-200mm f/4.5 AI (square rear baffel, 12/5 elements) optical cross section, at 80mm
Main access is via the front after the removal of the front retaining ring (secured via a set screw) - its easiest with rubber cones to get purchase on the front of the name plate to unscrew. Access to this area is useful as I've seen a number of samples that have fungus growth in this area - whether this is due to the push-pull design pumping mositure etc into this area is unknown but its certainly an area to clean.
Removed front retaining ring and front optical group, exposing the 1st/outer floating group and also screws securing front housing
The deeper internal group requires a longer lens spanner or a masons compass to unscrew and can be fiddly (zoom it to 80mm so its further up in the lens barrel). It is noted that over the production run of this lens version (same optical formula, with 12 elements in 5 groups), the internal construction changed. Serial numbers 7xxxxx had housing for the middle elements different to 8xxxx onwards with the latter having lens spanner holes that allowed removal of the full housing. This change of physical construction means that you can not swap components.
Deep location of 2nd/inner floating group before and after remove - exposes apeture blades
When reassembling the 2nd/inner floating group, ensure that it and its brass spacer are seated flat and correctly otherwise this may cause focus issues: I had misseated this and it meant that focus would shift significantly when zooming, and at 80mm objects are infinity focus would require the focus to be zoomed to ~7m according to the focus distance scale.
The rear elements are housed in an optical block screwed into the iris mechansim and requires removal of the apeture ring and a secondary base plate. The removal of the optical block may require you to remove the rear element group to get good purchase on the spanner notches to allow unscrewing of the remainder of the optical block.
The iris mechansim is secured by the chrome grab ring but unless you need access to the apeture blades, its not necessary to remove.
Helicoids
The helicoids are really simple in this lens. With the front retaining ring removed, you need to remove the zoom/focus ring (secured via a set screw) - ensure that you hold the front as you twist to avoid bending the helcioid/focus limiters.With the zoom/focus ring retracted/removed, you will access the 2x brass guides running along the central brass key - remove the 2x brass guides, unsecure the 4x screws (the ones going into the black section) on the front housing and lift off the front housing and you will have access to the helicoids. Remove the longer helicoid/focus limiter and you can separate the helcioids for cleaning.
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