On the weather sealing issue, seems all pre-1999 lenses have some basic form of weather sealing:
Chuck Westfall (Canon USA) has provided information about the weather sealing found in some pre-officially-sealed lenses.
According to Mr Westfall...
Yep. In fact, it was this very thread that resulted in the news post on Bryan's TDP site. From p.2 of this thread:
somehow i missed that
I'll do a little more digging...
Apparently, the 400mm f/5.6L is partially sealed. According to Chuck Westfall (Canon's tech support guru)...
My 'digging' consisted of contacting Mr. Westfall, and I forwarded his responses to initial and follow-up questions to Bryan at TDP (John = me, neuroanatomy is part of my day job ), thinking the fact that these 'unsealed' lenses do have partial sealing was pretty interesting and worth disseminating. In particular, the fact that a push-pull zoom like the 100-400mm actually has dust-resistant seals around the zoom ring is worth noting, since that lens is sometimes aka the "dust pump."
You're the person that asked about the gasket retrofitting? That would've been great to have, even unnoficially, or even implying voiding the warranty.
Other ones that also need weather sealing are the 35mm f1.4L...
I agree...but remember that for sealing on a lens to be effective, the body must also be sealed, and although some non-1-series bodies have partial sealing, only the 1-series are truly weather-sealed (the rank ordering for sealing is 1-series >> 7D > 5DII = 50D/60D).
At the moment i have a 7D. I thought about a 2nd body, a 5D Mk.II, but resisted the temptation and invested in lenses instead. I'll skip the 5D Mk.II and get a 1D when the time is right.
In fact i just got the 400mm, lack of full weather sealing and all. I thought the lack of IS would make it unusable (since it's a 640mm equivalent on APS-C), but it's not that bad. I'll just have to get some sort of weather protection when using it outdoors, other than this issue, my first impressions are positive. The 100-400mm was too cumbersome, i would be using it at 400mm mostly, and i got the 70-200mm range covered already. I'm not sure the 400mm f4.0 DO is fully weather sealed, but at the price Canon is charging for the DO you can make a bit of extra effort and go straight to the 500mm which is a far better investment (and would be even better if it included a chiropractor ).