70-210mm f/4 AF Nikkor on a D2x (ISO 160, f/4, 1/1000 sec).
Could a more expensive lens do it better? Probably not.
There's a sucker born every minute
One of the internet's single greatest myths is the 70-210/4-5.6D Nikkor. Originally marketed as a budget amateur zoom, it is now a grossly overpriced testament to how closely the public follows web page reviews. What makes the situation more egregious is that the hysteria surrounding this lens was fed by one review - whose author made a point that he might have had an exceptional example of the lens. Nonetheless, it is a top seller on Ebay. BAAAAAAA! That lens is not anywhere near the top of the bracket in its original target market or its current price range.
The challenge of the midrange zoom
Nikon has made 80-200/2.8 zoom lenses basically forever. These lenses have been huge. All of them are good. Their only real defect is the sheer amount of metal and glass needed to support good optical performance in a zoom. As you may know, it can take three times as many elements to make a good zoom as it does to make any prime lens between 80 and 200mm. The result is a big, heavy lens that needs a metal barrel for structural support as much as anything else.
The solution for people who actually have to hike around with lenses is a 70-210 or 80-200 that has a smaller maximum aperture, like f/4. The challenge in midrange zooms is making something that is useful, light, sharp and durable. Fortunately, the optical difficulties are relaxed considerably.
Nikon has made four compact AF tele zooms: the 70-210mm f/4 (subject of this piece), the 70-210 f/4-5.6, the similar-looking 70-210 f/4-5.6D, and the 80-200 f/4.5-5.6D. Because the last one is not really in the same league (and priced accordingly), I will discuss only the first three.
Why the 70-210/4 and not the "hot" 70-210/4-5.6D?
To prevent this from devolving completely into alphabet soup, I will refer to the three Nikon 70-210s by their version numbers.
v.1 70-210/4 (1986-1988 2-ring version). This lens, like a lot of early Nikon AF lenses, traces its lineage to Series E lenses, particularly the 70-210/4, a very solid lens.
v.2 70-210/4-5.6 (1988-1995 push-pull version). This was an all-new design, with a very compact overall length at 70mm and a fairly long one at 210mm (~6 inches).
v.2a 70-210/4-5.6 (optically identical, with D capability and faster focus gearing). This was an incremental improvement, and an improvement only if you believe that faster focusing and "D" flash operation make any difference.
Having sifted through this with several test lenses, I have come to the conclusion that v.1 is the best of the three, for a lot of good reasons.
1. The false economy of focusing speed. The allure of v.2a over v.1 and v.2 is based entirely on focusing speed. The need to quickly focus from 2 meters to infinity is, in reality, insignificant. Telephoto zooms are typically used at long range; it is difficult to find an autofocus lens of this type that cannot focus quickly from infinity to 60 feet (a pretty normal distance range). If you are shooting speeding race cars at incredibly close range, this might make a difference to you.
But there is another tradeoff. With a screw-drive Nikkor, fast gearing of the lens' autofocus mechanism is inimical to accurate focusing. Nikon's AF system is open-loop in S mode. That means that the camera focuses to where it thinks the lens should be and stops. This is how you can have an F5 track fast-moving objects just a few feet away: it predicts. The in-camera AF system looks at the focusing rate of the lens compared to turns of the AF motor (as detected by optical or electronic means, depending on the vintage). The lower the gear ratio (i.e., more motor turns to lens movement), the more accurate the computations (and the resulting movement) should be. This is why Nikon's really high-end primes (things like the: 28mm f/1.4, 105mm f/2.0, 180mm f/2.8) have surprisingly slow focusing rates. In a system like Nikon's, the correct way to speed up focusing is to use a monstrous motor and lenses with a slow focusing rate.
2. The forgotten economy of lens speed. A big difference between v.1 on the one hand and v.2 and v.2a on the other is speed. At the long end, v.1 is one whole stop faster. This is not something to overlook, considering that you need to use high shutter speeds with telephotos when shooting handheld (this need actually increases when you use cameras with DX-sized sensors). One stop can mean the difference between blurry and sharp. It can also mean the difference between functional autofocus and not. Nikon AF performance starts falling off at f/5.6; add a filter or a polarizer and it can go from "ok" to terrible. Remember, v.1 is only one stop slower than an 80-200/2.8 at all focal lengths, but v.2 and v.2a are more than a stop slower starting at 71mm and two stops slower at 210mm.
3. Sharpness. If you focus it properly and maximize the use of the Nikon AF system, v.1 blows away the other two versions in sharpness, especially in the near range. I am not sure why the conventional wisdom is that v.2 and v.2a are optical miracles; their performance was pretty dismal on film and equally dismal with digital. But then again, maybe I just drew 3 bad samples of the v.2/v.2a optics.
4. Distortion. This is a big deal, and a deal-breaker if you are taking pictures of things with straight lines - such as shooting the windows of a building. Both v.2 and v.2a, which share common optics, have distortion at both ends, particularly nettlesome at the telephoto end. The first version, by contrast, has no distortion that you can see.
5. Zoom creep and control schizophrenia. Nikon's v.2 and v.2a were part of Nikon's abortive fascination with push-pull mechanisms on zoom AF lenses (c.f., 35-105 f/3.5-4.5D, 75-300 f/4.5-5.6, 80-200/2.8 1st and 2nd, etc). These mechanisms allow the lens to be relatively compact at some settings but lead to sloppiness when you point the lens up and down. If you are used to using AF-s lenses, which all have second rotating rings for zoom, you can easily get disoriented when switching between push-pull zooms and 2-ring zooms. By contrast, v.1 has a zoom ring that turns - easy to harmonize with the rest of your Nikon optics.
6. The dust pump effect. When you are racking the zoom on v.2 and v.2a (as well as any push-pull zoom) you are sucking in air from outside into the lens. Push-pull zooms cannot be airtight, and they are great for getting dust into the vicinity of your digital camera's sensor. V.1 has a fixed rear element, and its zooming action has less potential for propelling dust into the mirror chamber of the camera.
What are some lower-priced options?
Other than the lenses described above, you actually have several other alternatives to v.2a. These are all well worth looking at. They all cost less than, and outperform, v.2a. Optical performance is compared on digital bodies. Don't discount the fact that the best alternative for you may be a prime lens.
75-300/4.5-5.6 AF. This is the one with the tripod mount. Not a short lens, but it has virtually zero distortion. Even though this is a 4x zoom, it is very sharp and even does well on the D2x. This is a push-pull zoom measuring about 6 inches (15cm) when in the 75mm position. 62mm filters.
Mid-to-long range / medium aperture performance
100/2.8 Series E (manual focus). Tiny, cheap and compact manual focus lens. Owning this lens will quickly disabuse you of the idea that cheap lenses cannot be worthwhile options. 52mm filters.
105/1.8 AI-s Nikkor (first version manual focus). This is Nikon's famous Sonnar-based SLR lens. It is the one with the silver nose. To use it on a modern camera, you have to have it "cut" (AI converted) or find one with the factory AI conversion. This is a sleeper on the D2x. 72mm filters.
105/2.5 P.C. Nikkor (pre-AI) Nikkor (chrome nose; first version manual focus). This is Nikon's famous Sonnar-based SLR lens (early versions are marked 10.5cm). It is the one with the silver nose. To use it on a modern camera, you have to have it "cut" (AI converted) or find one with the factory AI conversion. This is a sleeper on the D2x. 52mm filters.
105/2.5 AI / AI-S Nikkor (second and third version manual focus). The AI version takes a separate hood; the AI-s version has a built-in, sliding hood. These are not great wide open and close up on a D2x, but they are reportedly good under those circumstances with a D200. 52mm filters.
135/2 AI-s Nikkor (manual focus). This monster has all but been forgotten but is a cheap, sharp and fast medium tele that becomes a 200mm on a digital body. 72mm filters.
180/2.8 AF ED and 2.8D (both with the crinkle finish). The 180/2.8 AF Nikkor is a lightweight, high-speed, high-performance lens. On film bodies, they are equally sharp (and I mean, very sharp, from f/2.8-f/8. The second and third versions are identical with the exception of the D function (fairly useless on a 180mm lens anyway). 72mm filters.
What about going upmarket?
Yes, another alternative is going to the f/2.8 zooms as an alternative to the 70-210/4-5.6D. You might find with the 80-200s that top-end performance is achievable at surprisingly low prices. I am providing the following notes as a quick guide. I like the first one on the list the best out of all of them.
AF-S 80-200mm f/2.8D (both with the crinkle finish). This is the king of the big, fast midrange zooms. Autofocus is so fast that it may as well be mind-controlled. Outresolves the mighty 180/2.8 at infinity.
AF-S 70-200mm f/2.8G VR. The king of bling with about the most obnoxious ED-IF plate ever put on a Nikon body. Simul-brass. Solid optical performance but not compatible with some digitals (like the Kodak full-frames). VR does not work with bodies before the F5. Will autofocus with the F4 but with no other body before the F5. Not that it matters, since it doesn't have an aperture ring for use with cameras before the F5.
AF 80-200mm f/2.8D (two rings with tripod socket). This is yet another internet hype-up by one man, but I would tell you to skip it unless you have a camera that can't do AF-s or want to shave one pound off the AF-s lens' weight. Build quality is substandard. Although the body is metal, the focusing ring is plastic, and certain of the parts that run the manual focus mechanism are simply melted into the plastic of that ring. The inevitable failure (symptom: lens won't lock in M or A on the focus ring) is a Class C repair costing $241. I experienced this one firsthand. Taking the rubber focusing grip off and seeing this kind of construction is like looking through a keyhole and seeing your sweet old grandmother strangle a kitten. Get a new one with the 5-year warranty (since you'll need it), or get the AF-s.
AF 80-200mm f/2.8D and f/2.8 (the earlier versions). Solid, workmanlike lenses with relatively slow focusing but excellent optics and build quality. You rarely see these two sidelined. In fact, of all the 80-200s, these are the ones you most often see in rough shape, a testament to the fact that someone actually uses them.
Don't count these out immediately - you may find that your camera bag is, in fact, big enough for top-flight lenses.
In conclusion
The 70-210/4-5.6D is a great example of an internet-driven phenomenon driven by one variable to the exclusion of all others. Don't fall for the pomp and empty promises of focusing speed; it might cost you in optical quality or usability, if not dollars.