I posted only a few images shot while in Vietnam recently. (See the Photojournalism section.) The reason is that most of my work was boring - I was there to do a lot of documentation work. The safe water team visited possible future sites for installing systems, as well as sites to see how systems were working that had been installed for two years. So, a lot of the photos were just head-on shots of a clinic or school, intended for inclusion on a database along with GPS data.
MEDRIX also wanted me to shoot images that could be used for fund-raising, so I needed to included images of
MEDRIX personnnel and logos that might not be of interest to the general public. That left little time for "fun shots."
But, in taking over 1,700 frames, I found out once again that I needed fast lenses. Far and away I used my 17-40 f4L on my 30D the most because I needed to get in tight most of the time. My EF-S 10-22 was used on occassion, but its hard to get a good face picture with it. I also used my EF 28-135, mostly when in a large room and I could play with the depth of field a little. (Yes, I would love a 24-105 f4 IS. Anybody want to donate one?

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But, as good as the 17-40 f4L is, I really needed something faster. As I will be shooting a crop camera for the forseeable future, I think the lens I need to get is the EF-S 17-55 f2.8 IS. Besides being a stop faster, it also has IS. There were a lot of shots where I needed IS as the light was very poor and even ISO 1600 wasn't quite fast enough. (I could have shot 3200, but I didn't have Noise Ninja on my laptop.) True, I would love the new EF 16-35 f2.8 - but it doesn't have IS. I don't need to stop action - I need to compensate for my shaky hands at low shutter speeds. By the way - I did try using my monopod a couple of times, but it was just too clumsy to use in crowded conditions.
I also need a system with weather sealing. Yes, I know I can get that with a 1 body and L lenses, but I doubt I will see a 1D anytime in my future. Canon - how about sealing the 5D? The environment in Vietnam is pretty tough on electronics - sudden showers and the high humidity calls for rugged gear and lots of desicant in the camera bag.
Speaking of bags - I love my Lowepro SlingShot 200AW. I could easily carry two lenses and my flash unit in the bag, and my 30D on my shoulder and be ready for just about anything. The bigger Tamrac bag with all my gear stayed in the hotel room while I worked out of the smaller 200AW. The only thing I could not carry was my 70-200, but since I hardly used it anyway, it was not missed. In this case, I was able to change from my 28-135 to my 17-40 very quickly without having to take off the bag.
My next camera
must have dust removal. I had to change lenses a lot, and I soon had a big dust bunny on my images. Trying to clean a sensor in a hot van while traveling from one site to the next was out of the question, so it just meant more Photoshop work later.
Finally, I need to get a flash brakcet. Before I left on the trip, I had shot some "grip and grin" images of the local mayoral race. While bounce flash works okay in most cases, as it did in the mayor's fund raiser, the very high ceilings of Vietnam negate that, and a flash bracket would have helped the "graduation" pix of the physicians who completed the English medical terminology course my wife taught.
But - no real complaints. My gear worked as it should. It just needs a better photographer.
EDIT: I forgot to ask this question in the original post.
In one case where I took pictures of my wife teaching, the room walls were ceramic tile, and everything was white. While this alone challenged me to find ways to make the shots contrasty, the real problem had to do with reflected light. I noticed it before I began shooting, and put a circular polarizer on my 17-40. After much twisting and turning, I could see no change whatsoever in the reflections. I have used a CP many times before, but I am curious to know why it didn't work this time. Any ideas? (BTW - it's a B+W filter, so I don't think its a quality issue.)