Just moved from a T2i to a gripped 5D1 with roughly 18,000 shots, and looking for some cheap lenses to get my feet wet in full-frame for an upcoming trip to the Dominican Republic. In the past I have primarily shot portraits either with natural light or radio-triggered manual speedlights (ala strobist)
The only usable full-frame lens I own is a Canon 50mm 1.8 II. I say "usable" as I picked up a mold-filled Tamron AF 200-400/5.6 for pennies thinking I would one-day send it for cleaning, but never did for fear the cost and result wouldn't be worthwhile.
I would likely purchase 2 zooms if I had more money (24-105/4, 70-200/4) or cash to burn (24-70/2.8 II, 70-200/2.8 is II), but as it is, I cannot afford that route.
Instead, I am currently considering secondhand:
$200 - Canon 28-135 (Walkaround)
$250 - Canon 24/2.8 (Wide Angle)
$350 - Canon 85/1.8 (Normal, Low-Light - to join my 50 1.8)
$400 - Canon 100/2.8 Macro (Short Tele, Macro)
1) Should I buy a Canon 28-135 for convenience at least for my trip? I know the 5Dc has no sensor cleaning capability, so I fear dust with changing my lenses in the Dominican. 28mm should be sharp and wide enough to capture stopped-down tripod stills of the old city right? My 50 can handle low-light and portraits, and although 135 won't be long enough for wildlife, maybe I can catch a few candids.
2) Later on, should I drop the extra $100 or so to get the USM version of the 100mm macro so it is more useful for portraits, or is the non-usm fine?
3) Is the 85mm necessary? Its so close to my 50mm, as well as the 100 in focal length. Any other decent, budget lenses i'm missing?
4) Finally, what kind of hiking backpack do you suggest that can accomodate a laptop, as well as a light stand that collapses to 20"? I say "accomodate" meaning if it can't fit in, at least it can strap on securely and unobtrusively.