(This post is from an email conversation with a coworker. I thought the content might be useful for others.)

Q:  What’s your favorite long lens, the 300mm f/2.8?

A:  Long lens.  Hmmm.  That is SO dependent on application.  I trust Thom Hogan’s reviews a lot.  There’s also a good discussion here.

The 300/2.8 is top notch.  (I have two of them.  The AFS mk 1, and the AFS VR I.)  It’s the easiest to travel with on airplanes.  But I’ve finally had to admit that it doesn’t give the level of sharpness I want when I add a TC, especially the 2x.  And for what I need a tele for (birding), 600mm or more is often necessary.  Bottom line for me is that the 300 is too short.  Another good thing about it, though, is that it is very hand-holdable (if you have strong arms), especially the VR versions.  Available for $3-5K depending on the model.

Some like the 200-400/4.  It’s sharp until you get past 100 yds. or so.  When you’re shooting very dynamic subjects (like whales) it’s handy to be able to have a wider view to find your subject and then zoom in for the shot.  It’s often hard to initially frame your subject with a longer fixed lens.  And the 200-400 is very hand-holdable if you have the arms for it.  Can be found for $5K in great shape.

The 400/2.8 is probably the sharpest of them all, but is very hard to travel with on airplanes.  It’s too big to be hand-held.  Ever.  That means you can buy an older AFS mk I or mk II since you’ll likely never use VR.  They’re all incredibly sharp.  Decent with TCs, too, so it can be a decent 800/5.6.  Great for sports and wildlife.  Can be had for $5-7K for the older non-VR models.

The 500/4 is less difficult for travel, very sharp, and barely hand-holdable for short bursts.  Many view it as the practical sweet spot for wildlife.  I’m looking for a 500/4.  But that’ll run 6-8K for a current VRII, which is the model I want so I’ll have the best shot at hand-holdability.  I missed a mint VRII with all of the optional feet and camo covers a few months ago.  Just took me too long to decide to part with that much cash.

The 600/4 is the ultimate for wildlife.  Will always be on a pod, so the VR isn’t necessary.  With your new D4, the AF will work even with the 2x TC.  You can find decent AFS mk I or II for $5-8K.

Don’t overlook the 200/2.  You’d love that one with video, and folk say it makes a very decent 280/2.8 or 400/4 with the 1.4x or 2x.  And it’s cheap!  😉