"The more I see the less I know for sure." --John Lennon
It seems that my take on the exotics provoked a lot of discussions in a lot of places (as well as a fair amount of email in my In Box). Let's see if I can be clearer about the pluses and minuses of your various options. But first, some background material you need to pay attention to.
In order of optical results, from best to worst I will use the following specific words: superb, excellent, very good, good, fair/decent, poor. Superb is better than excellent. Very good is better than good. And so on. Personally, I'll use any lens that's very good or better. I balk at using one that's just good, though you might not (more on why that might be in a bit). I try to completely avoid anything that's just fair, and obviously don't even consider a lens if the results will be poor.
These observations are based upon examination of images taken in the field as well as MTF testing I do. I place more faith in actual images than MTF results for a couple of reasons. First, MTF tests are one of two things: either a direct measurement of the lens at maximum aperture without camera (manufacturer's tests), or a test of the complete resolving system (camera and lens, typically via something like Imatest). In the case of the latter, how well you've set up the test rig and which camera you use will impact your results. It takes a lot of patience to get a meaningful number in MTF testing, and then it might not apply to another camera, so you have to test all over again.
Beyond that, there's the issue of "optimal image quality" versus "better than I've experienced so far." Some of us have been working with the exotics for 20 years or more and have seen images from the very best practitioners using all these lenses (remember, I was once the head of Backpacker, and I spent much of my time trying to improve the image quality used in that magazine, so I looked at tens of thousands of outdoor and nature images as a result. If I see another bear head shot I might get sick). In my own shooting, I spend a lot of time on optimization of data collection (better data means better image quality out the other end).
400mm f/2.8, 1/800, D3, hand held from boat
I believe you have to be careful to filter statements coming from someone who moved from a 80-400mm to a 500mm, for instance. They will be enamored by what the 500mm does. The results will look great to them, and they can't imagine better. That's because the 500mm f/4 will simply produce visibly better results than the 80-400mm at its extreme. Most people can clearly see that. The same is even true if they moved from an 80-400mm to the 200-400mm: you'll get the same gushing admiration. Yet the 200-400mm is no 500mm, and I've come to believe the 500mm is no 400mm when it comes to edge acuity wide open. Further, the 200-400mm is not even close to the 400mm at 200+ yards (assuming atmospheric conditions allow you to shoot that far ;~). Put a different way, we can, with much shooting and analysis, put these lenses on a scale of worst to best for a particular situation.
I'm not infallible, and I will be the first to admit that these are still simply my opinions based upon my experience. With tens of thousands of people reading this (maybe hundreds of thousands eventually), there's bound to be plenty of folk who have a different experience and opinion. I have no problem with that. Others value small things differently than me. And when we get up into these exotic lenses, there are a lot of small things that are different, so there are a lot of things that will trigger people to form different opinions. The point of this extended discussion is to try to be as clear as I can in what I see and what I've experienced.
Keep all of the above in mind while reading what I write about the individual lenses.
So let's look at each of the lenses I've written about individually:
- 200mm f/2. You have a superb 200mm f/2, a very good 300mm f/2.8 (with TC-14E), and a very good 400mm f/4 (with TC-20EIII). That latter may be surprising to some, but the lens+TC is within shouting distance of the 200-400mm f/4 for most 400mm work, especially if there's any distance between you and your subject. The pluses are that it is very transportable and reasonably compact, making for a smaller bag, and that you can hand hold it (assuming your arms are up to benching 9+ pounds all the time). The minuses are that it isn't exceptional with converters, just very good. Sports photographers really ought to pay more attention to this lens, in my opinion, but for wildlife shooters it's not optimal.
- 300mm f/2.8. There might not be an optically better exotic lens wide open than this. You've got a superb 300mm f/2.8, a very good 420mm f/4 (with TC-14E), and a usable but only good 600mm f/5.6 (with TC-20E III; and you really need to stop down with it). The pluses are that it isn't outlandishly big or expensive (just moderately ;~) and that you aren't going to get better results from anything else at 300mm. The minuses are that it doesn't give you a lot of reach without converters, and it's one of the optically weaker ways to get to 600mm. Again, this is a great sports photographer lens, less so wildlife.
- 300mm f/4. A darned good lens optically, and the bargain of the bunch. You've got an excellent 300mm f/4, and a usable (good, to be consistent with my other terminology use) 420mm f/5.6 (with TC-14E). The pluses are that it is small and transportable, and that it's far less expensive than the others in this list. The minuses are that it really only fully delivers at 300mm. You're weaker at 420mm than most of the other routes to get there (perhaps slightly better than the 80-400mm at 400mm). You have a dimmer viewfinder. You don't have VR. This is typically the lens I suggest to someone that is cash strapped but needs to be in the 300-400mm range with something better than the 70-300mm and/or 80-400mm.
- 200-400mm f/4. A bit odd in that it's superb close in, but only good to very good far out (and it depends upon how far away the subject is). [An aside: stop showing me 400mm images from the lens at distance that you think are good. They aren't close to what the 400mm f/2.8 produces in the same situation. I don't know how many times I've repeated that test standing next to someone with the 200-400mm, but there's a clearly visible difference. My confidence level is very high on that statement.] You've got an excellent to superb 200mm, very good to superb 300mm, and good to excellent 400mm with this lens, again, partly dependent upon subject distance. You also have a usable (fair) 560mm f/5.6 (with the TC-14E, and which you should be shooting at f/8). The pluses are that this is another lens that isn't outlandishly big and travels well. The minuses are that you're starting to get into the deeply expensive territory and you won't optically match what others can do at 400mm and up. Still, this is a good all-around lens that's flexible and convenient. It works well on safaris where you can get close to animals (South Africa, Botswana, some Kenya) but not so good for safaris/trips where you can't (Tanzania, some Kenya, Yellowstone, Alaska). It works superbly for sports in which you're less than 50 yards from the action, less so as you get further away.
- 400mm f/2.8. You have a superb 400mm f/2.8, a very good 560mm f/4 (maybe excellent; it's a close call), and a usable (fair to good) 800mm f/5.6 (in my experience, the TC-17E is good, and gives you 680mm f/5). No one is going to match you at 400mm. No one. The 500mm user standing 100mm worth of focal length behind you isn't going to quite match you, either, though they'll come darned close. The pluses are all centered on that optical quality. You also have a bright viewfinder, which a lot of people seem to forget about. The minuses add up fast: weight penalty, price penalty, and a handling penalty (not hand holdable).
- 500mm f/4. You have a superb 500mm f/4, a very good 700mm f/5.6 (with TC-14E), a usable manual focus (fair) 1000mm f/8 (with the TC-20E III). The pluses are that this is the most manageable of the long reach solutions in terms of weight and travel, and it's reasonable to position yourself 500 to 700mm away from most wildlife. The minus is the price, and to a lesser degree the fact that TC's don't really add a lot of flexibility (I really consider this a 500 or 700mm lens only). Also, the viewfinder is dimmer. Wildlife photographers tend to gravitate towards this lens because it is the best of the reach/weight compromises. Sports photographers tend to avoid it because the f/4 aperture isn't conducive to night shooting.
- 600mm f/4. You have a superb 600mm f/4, a good (possibly very good) 840mm f/5.6 (with the TC-14E), a usable manual focus (fair to good) 1200mm (with the TC-20E III). The plus is this is as long a lens as Nikon makes and sells at retail at the moment, and that it is very well balanced for its size and weight. The minuses are price and the fact that the size and weight are out-of-category for most folk, especially since you'll be using a bigger support system than the 200-400mm and even the 500mm user. Again, the viewfinder is a dimmer. Small bird photographers tend to gravitate towards this lens because they want big to shoot small. Personally, I find it to be too much lens for most mammal photography, except in those places where you can't really get close, like Denali NP, Alaska.
The Balancing Act
You balance the following things when you make an exotic decision (even when renting): size, weight, necessary support, reach, optical quality, flexibility, and cost. Not a single lens rises to the top in all those categories, which is one reason why there is disagreement over which lens to get. Different photographers value different things differently. In general, though, it works out this way for most shooters:
- If your highest values are size, weight, flexibility, and cost, I'll bet that you'll go for the 200-400mm (and that you're using a DX body).
- If your highest values are size, weight, and cost, but you also highly value reach, you'll go for the 500mm.
- If you value reach over everything else, you'll go for the 600mm, and right now you should be putting that on a D3x body whenever possible.
- If you value optical quality over everything else and need as much reach as you can get without sacrificing optical quality, you'll go for the 400mm (again on a D3x), or you'll argue that you aren't giving up much at 500mm and getting an extra 100mm ;~). I'm in the former group, a large number are in the latter.
- DX users should be able to get by with 400mm, and most probably don't need to go beyond 500mm. I believe that the logical choices for them, in order of most preferred to least, are probably 200-400mm, 300mm+TC, and only if they have the support system and they really, really need the reach: 500mm. In my experience, you really need to AF Fine Tune the DX bodies and you need to fully master focus the longer the lens you use. The notion that DX equals a free 1.5x teleconverter is wrong on a lot of fronts, but counting on using DX to give you more reach over FX is harder to put into practice than it at first seems. It can be really difficult with moving subjects and lesser AF systems that can't be fine tuned, such as on the D5100.
- FX shooters, especially top end amateurs and pros, need to match their lens choice against their most likely subject and shooting position (e.g., location, animal type/size). But in most cases it's going to mean 400mm, 500mm, or 600mm. For me, the preference is in that order. For others, they'll put it 500mm, 600mm, 400mm. Still others will say 500mm, 400mm, 600mm. There are good arguments for all three lenses, but make sure that you understand the bias of the person making the statement you're relying upon in making your choice. Too many wildlife photographers get caught up in the head shot game and go for reach over everything else. I'd rather have optical quality over everything else, and I think that showing environment is as important as showing animal. Don't undervalue a highly sharp f/2.8 aperture over f/4 reach. I think it gives me more options. Yes, it means I have to work to get closer sometimes, and yes, I'm using a heavier lens than the 500mm, but I don't think that's held back my wildlife shooting one bit.
- Here the lens you need will be dictated by the sport you shoot and your position relative to the action. For example, I find that the 300mm f/2.8 is often enough for sideline football. Most of the positions I'm taking up tend to be no more than about 20-30 yards from the expected action. But soccer is a different beast entirely, and you're in a relatively fixed position while action may be taking place the entire pitch away from you; even a 600mm feels weak sometimes. Baseball puts you in fixed positions, too, and you'll probably be too tight for one corner of the diamond, just right for two (plus pitcher), and not long enough for the fourth with your main lens. For me, baseball is a two-camera sport. Well, technically, every sport is a two-camera sport for me, as I'll always at least have a wider option (24-70mm or 70-200mm) hanging on a strap around my neck. But baseball is a sport where I might bring two longer lenses, leaving one set up on a fixed position and fired by remote.
The notion that one lens is better than another is also driven by a rude reality in Internet discussions: we can't afford more than one. That single fact drives almost all the "which lens should I get" discussion: you'll only get one, so which one will it be? That means that you have to listen carefully to all the discussion and make sure you pick up the subtle points (e.g. viewfinder brightness, travel friendly, etc.) before making the correct decision for yourself. You'll often hear strong arguments from others that made the decision before you, but who are actually defending their decision--they might not have much, if any, experience, with the options they didn't pick. I've written forcefully against the "get as much reach as you can" philosophy that seems to drive some. I've tried that route, as has my assistant, and we both backed off from going the 600mm route. I get a lot of criticism for that and for my personal choice of the 400mm f/2.8 as the lens I've kept. Still, I'll put my wildlife photos up against anyone's.
Finally, a comment about sharpness and telephotos. Most photos we take with the really long lenses are of centralized subjects, and often the things in the corner of the image aren't at the same focus plane as the subject anyway. This tends to be true of both wildlife and sports photography, and is more true as you approach full frame with such subjects (but flips back if you manage to reach or get closer than full frame). How sharp the central area is will be key. How sharp the edges are will be less so. Thus, corner-to-corner sharpness is an attribute I'd value less than a very large and highly sharp central area. As it turns out, the TC-14E on most of these lenses produces soft corners, but still manages to keep the central area acceptably sharp. The TC-20E III, on the other hand, tends to stay sharper out towards the corners than the other teleconverters, probably due to the aspherical elements in its redesign. Thus, on the 200mm f/2, for example, the TC-14E produces a sharp central area and soft corners, which I happen to be fine with, while the TC-20E III produces an almost as sharp central area that stays sharper into the corners. Some photographers reactions to these lenses and the use of converters on them will be driven by what they think about corners.
One last little bit: we get caught up in discussions of all these great lenses. But don't forget the pictures. Consider this photo taken with the 70-300mm VR:
It's sharp. It's involving. It wasn't taken with an exotic. Lenses are just tools. While I want the best tool I can get, it doesn't stop me from using lesser tools when that's what I've got available to me. I'm not sure I could have focused and framed this with the 500mm (I'm twisted around in the front seat of my vehicle shooting almost straight up, and I had almost no time to capture the shot).
Disclaimers: I regularly and repeatedly have used the 200mm, 200-400mm, 400mm, and 500mm. I used to own and regularly use the 300mm models (since sold). I have used NPS or student 600mm lenses a number of times. Further, I've had field experience with almost all iterations of all those models (AF-I, original AF-S, AF-S VR, and AF-S VRII). Most of my shooting with these lenses has been wildlife, of which I spend an average of 5-6 weeks shooting each year). Some of my shooting with these lenses has been for sports, of which I spend an average of one to two weeks a year shooting. While those are not my "normal" preferred subjects, I do believe that I'm comfortably professional in both types of shooting.