That's the whole point. If you read my post [snip]
I wouldn't ever disagree with your overall argument - that people weight different lenses by cost and utility. It would help explain my thinking if I highlighted the part of your post I was responding to:
I think it is wrong to assume that low-cost lenses don't affect sales of high-cost lenses. Let's go back to the 300mm zoom example. Canon has announced a $1,500 lens. Tamron has announced a $400 lens. Tamron is marketing their new lens as the "sharpest ever." If that proves to be the case, will a sharp, good quality $400 lens cut into the market for a $1,500 "L" lens.
"Sharpest ever" is pretty strong language. I was cautious about reading too much into your words there, but it made me look at Tamron's specific wording and claim of "unparalleled optical performance." They didn't say sharpest ever (i.e. of all lenses) but they come pretty close; they may be deliberately vague about what other lenses comprise the "class." I conclude that they want everyone to think that way, even if it's an unreasonable claim (not that I know this to be the case - in fact I'm leaning towards the Tamron being almost or just as sharp as the Canon, and more consistent across the frame too). My point is only that, and I was trying to see if I couldn't unravel their marketing a bit. Similarly, a lot of the praise for the Canon 70-300mm seems too strong, too, after the release of its own MTF chart. We get one or two cherry-picked pictures from them (the only I've seen that was useful was the full-frame cat picture from a 5D Mark II, which looks very nice though perhaps not up to the standards of a safari or in displaying the result from challenging lighting situations). I feel that the 70-300mm L charts look astonishingly like those of the 100-400 of 1998, reversed - with the 100-400 seemingly better at the far end, and the Canon 70-300mm L looking better at 70mm, like any other 70-300mm zoom. I will feel a lot better about all this when more impressions and photo samples appear!
There is also a danger of uncritically assuming that Canon knows best and Tamron is fated to short as usual (so goes the ancient prophecy / stereotype). Obviously we don't know yet, but right now it looks very good for Tamron. All of Canon's previous 70-300mm cheapies (even the DO, which isn't cheap) seem to be blown away (remembering Michael Reichmann's warning against comparing MTFs from different companies) by both the new Canon and the new Tamron. The comparison is lenses that start out at 60-80% contrast and go down from there, across the frame, against lenses that start out above 80%, maybe even above 90%, in the center.
It's interesting to point out that the Tamron 70-300 chart is smoother than the Canon one (not to mention much smaller and harder to read). One possibility is Tamron's chart could be less precise / incorporates fewer samples than the Canon one, but I don't see an issue in how they present their chart that way (aside from the really horrible
decision to make it tiny). If I can compare the two MTF charts, the Tamron may well be just as good as the Canon (in terms of MTF - versus the Canon, the possibility of the Tamron's aperture closing at a different rate, or sharpness improving at a different rate when stopping down, complicates things), the Tamron charts may well point to it being every bit as sharp as the Canon, and not just starting off about as sharp as the Canon, but holding that sharpness almost all the way across a full frame, where the Canon 70-300's sharpness starts dropping off pretty quickly. It seems safe to assume that these good traits improve as it's stopped down.
You've presented me with a welcome opportunity for me to ask myself
how much of a premium I put on the (assumed) Canon-issue autofocus reliability advantage (assuming my camera is good at AF; it isn't), IS (four stops versus three? Seems to be the case for the Sigma 70-200 f/2.8 versus the Canon one, as well; I doubt I'd like to press IS that far in most cases), weather sealing, the anti-smearing coating, and the white metal body. If I were out there shooting pictures from my own budget for a living, I wouldn't put a $1100 premium on the 70-300 unless I really thought it had some kind of durability advantage, or it had a proven edge in image quality and autofocus hits (at the $400 price, you can replace the Tamron easily, or stock nearly four for redundancy before you could get a single Canon 70-300mm L; obviously I'd not like to carry around that much in case of emergencies, but having an extra with the luggage could be extremely useful).
There's also a lot that could be fairly critical in creating a pleasing image that one or the other lens does better or worse than the other, which is hard (or impossible) for me to guess from spec sheets, with blur and color reproduction being the two that come to mind.
I'll admit that I have a bias towards hideously expensive, special-purpose lenses, which is why my personal lens collection is so unbalanced towards everyday shooting
It's been great for technique though.
My final thought is that this is, on the whole, looking to to be a possibly disappointing end of the year for Canon. If the 70-300mm's reputation ends up as "it's metal and white but otherwise $1100 more expensive than the Tamron," this will be the second relatively high-profile, excitement-causing announcement that got undercut by the competition - in this case the $1100 price difference leaves the possibility of it being looked at as another Canon entry undercut by the competition.
I won't say that 2010 was a wasted year - facts, that the 60D received such criticisms and price competition, despite its great new (may I say innovative
?) features, and that the Canon 70-300mm has strong competition, augur well for photographers. We are getting much needed refreshes of some critical components, more options at price ranges suitable for different budgets, and apparently more competition overall. I suppose this was expected, after the incredible, economy-proof growth of the DSLR segment around the time I got my T1i, with sales records being surpassed in shorter time than ever. From a snip of a Canon announcement off DP Review earlier this year:
[quote# In 2003, the 20 millionth EOS camera was produced, doubling the previous 10million landmark in just six years
# In December 2007, the EOS seriesâ€™ 20-year anniversary, production of EOS SLR cameras rose past 30 million â€“ just four years after passing 20 million
# In April 2010, Canon reached its current 40 million production milestone â€“ rising from 30 million units in just two years and four months.[/quote]
The 50 million EF lenses milestone was reached this year, as well.