I am 20 yo male from Canada (Indian background), traveling ALONE to India (Mumbai, Assam, Sikkim, Orissa) and then going to Thailand (bangkok, and wherever else I go) and also Cambodia. Estimated travel time will be 3.5 months. I will be living out of a backpack (65L), and want to pack minimally. I have a Canon 30D with 3 lenses (17-40 f/4, 50mm f/1.4, and 100mm f/2.8) and wanted to know if any have had experiences with SLR around these areas or what other people think? I am mostly concerned with how to pack properly? Whether to take a full separate backpack (Tamrac 6 adventure) for it or to pack it into my huge backpack. And also safety, I would like to not get my gear stolen if possible, and I don't want that weight in my head whilst traveling. There are many experienced people here and wanted to hear from them or anyones suggestions/recommendations.
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Ultimately of course, you'll need to temper any advice you get here with your own likes and dislikes; however under the circumstances you describe I would recommend leaving the DSLR at home and taking a high end (prosumer) digital camera if you can afford it.
I really wanted a DSLR for my RV trip (which has a lot more security & room for camera's then a backpack trip). In the end, I decided to stay with my Sony Cyber Shot, which is considered a high end digital camera I think. There have been a couple of occasions where I wish I'd had a DSLR (mostly for a bigger zoom, my camera has a 12x zoom - adequate for most shots, but on occasion not). 98% of the time, I'm really glad I've got the smaller, lighter weight camera.
I get great pictures, have most of the settings and controls necessary to 'tweak' the pictures (Manual shutter speed and aperature controls, etc.) - althought most of the time I leave the camera on 'Auto', which works fine for most shots. The camera is lightweight enought that I'm not hesitant to carry it around all day on hikes, up lighthouses or monuments (for me, a DSLR would probably feel very heavy by the time I got to the top).
Also, while I'd hate to loose it - it doesn't cost nearly as much as a nice DSLR setup with all the lenses, so I'm not as afraid to haul it around as I would be with a DSLR.
For you of course, another big advantage is that the smaller camera wouldn't take up as much room!
I was taking pictures of some egrets and heron yesterday, so had the camera on a tripod, when an osprey flew by. It was clumsy and difficult to grab the camera and tripod to try to track a bird in flight that was close by as this one was. So I'm becoming a big believer in keeping the most powerful and easy to use hand held camera that you can afford close by for occasions such as this. Scenic shots aren't quite as fleeting - you can do quite well using a big camera or camera tripod combination. But I think my best pictures are the spur of the moment ones - you just happen to see a shot and point and click. There's a lot to be said for keeping a small, powerful and quick camera close at hand.
Several companies make really good 'prosumer' digital cameras. While I've really liked the Sony and it's very well laid out, the Fuji may have better color. Olympus makes one with an 18x zoom, but I've heard some less then great reviews about the brand.
Whatever camera and/or lens you decide to take - seriously consider optical image stabilization (especially witsoh big zoom lenses). I have become a big believer and will probably never buy another camera without one. We have a couple of other camera's on this trip, but I always come back to the Sony because the pictures come out so much better on a consistent basis - since I zoom in a lot (especially for wild life), and rarely take the time to set up the tripod, the image stabilization makes all the difference in the world.
Now, having said all that, my pictures aren't really professional quality by any measure. The pictures are great for my personal use, but if you want professional quality pictures - you'll have to factor that into your decision. You can probably still get great pictures with less than a DSLR (my problems may be the photographer, rather than the camera), but there are reasons so many pro's use DSLR's...