Originally posted by falconeye I don't think the Nikon was crippled to protect the fast tele primes or the 200-400. IMHO, there is no evidence. And that was my entire point I wanted to contribute to the discussion.
fair enough. But it is clear that both Canon and Nikon, having thrown their lot into full frame, (unlike Pentax) only offer a paucity of pro-level lenses for their DX gear (in fact Nikon offers precisely ZERO pro-level DX lenses. For me that is telling). As near as I can make out, Canikon are primarily using their DX cameras as "stepping stones" to encourage buyers to upgrade FX where the real profits are. As such, they are clearly making lenses to address marketing concerns and they are not above adjusting the behaviors and specifications of their systems to maximize profitability.
Given that DxO rates "systems" then it would stand that were the Pentax 60-250mm lens to deliver "only" the same overall quality as the Nkkor AF-S 80-400mm lens then my comparison system shots should have (in theory) clearly demonstrated such an IQ difference having used the K-3 sensor (after all, there is little contention that the D800 sensor is superior to the K-3 sensor as per DxO). Instead, what my un-scientific tests between K-3 + 60-250mm vs D800 + AF-S 80-400mm show are that 20"x30" prints produced from each system are of similar or equal overall IQ. In other words, the prints I have produced so far are basically indistinguishable at arms length. If my tests are any indication, then it strongly suggests that the 60-250mm lens must be therefore overall superior in order to deliver a similar overall system IQ versus a Nikon system whose D800 sensor is clearly superior to the K-3. Consequently, it is not a stretch to make the claim that the Nikkor AF-S 80-400m is likely not as good as Nikon *could* have made it (without a doubt, Nikon is one of the premiere lens manufactures in the world and they have the ability to do just about anything they set their hearts to). The obvious reason they might not go overboard with the 80-400mm would be to protect their "cash cows" which include the classic 14-24mm, 24-70mm, 70-200mm, and 200-400mm lenses; all superb and carrying a premium price. That is my contention. While there is some evidence to support my contention, I will admit there is no way to prove it. But I'm standing by it -- at least until Nikon proves me wrong.
In the meantime, companies like Pentax, Olympus, Panasonic, and Sony are pushing the envelope and seem to be delivering better value as of late. Gotta love competition to keep you honest!
YMMV
M