After further thought, here's what I'd like to see:
- A 50mm f/1.0 reissue (optionally in a version 2)
- A 600mm lens that is short enough to fit in a typical camera bag
- A 12mm (or wider) rectilinear lens
- An EF superzoom with more reach than the 24-105, but without massive zoom creep problems
Not holding my breath. I'm expecting a pony long before any of these things, with the possible exception of the last one.
Regarding the last one, do you mean a non-L lens? The 28-300L has much more reach than the 24-105L, has IQ that's basically equivalent across their respective ranges, and I certainly never had any zoom creep issues (that's why there's a zoom tensioning ring, and if yours wasn't wroking properly, the lens needed service).
I've considered the 24-300, but it is kind of a whale. What I'd really like is something closer to what a 17-135 does on a crop body, but on a full frame—something more along the lines of 24-200, ideally a DO version.
And yes, the lens creep from h*** I experienced was on a 28-135. I sent two back before giving up on that one. Not only was it not as long as I'd have liked, but it just felt insanely cheap, even when compared with the kit lens that came with my original Digital Rebel.
Regarding the shorter 600mm lens, that's where diffractive optics come into play. The 400/4 DO is physically shorter than both the 300/2.8 IS II and 400/5.6 lenses, and only 1 cm longer than the 300/4 IS. If I had to guess, I'd say a 600/4 DO might be ~14" long, about the length of the 400/5.6L with its hood extended. Based on published patents, Canon is still actively working on DO technology.
Yeah, but 14 inches is still hopeless unless you're not planning to carry any other lenses but that one. You won't find a camera bag that will hold something that big unless it's one of those giant VHS bags from the 1980s, and even then, it won't hold your camera along with it. So at that size, it's still a hard-core specialty lens that you'd buy only if you plan to do a lot of sports shooting where you have to have the reach, and where you're pretty much just going there to shoot with that one lens from a single spot for an extended period of time.
Here's what I keep thinking: Almost all of the space that a long lens takes up is just air. If you collapsed that giant 18" long 600mm lens down to where the glass was touching, it probably wouldn't be that much bigger than my 70-300, give or take, even without diffractive optics. With DO, it might even be smaller. If they can make lenses where the focus mechanism moves elements precisely, other than the manufacturing complexity inherently resulting in more QC rejects, what's so much more difficult about making all
the elements move, allowing the entire body to collapse like an old-style telescope?
(Yes, I know it would be a pain in the *** to engineer, but it would make those sorts of lenses a lot more usable by ordinary folks.)