I'm going on my honeymoon to Thailand, Cambodia and Vietnam in June for 4 weeks.
I'll bring my Canon t3i + 15-55mm and a 55-250mm lens.
This will be my first travel like this and I definitely want to take some awesome pictures.
I don't have a Flash and I want to buy a Canon Speedlite 430EX when the time comes.
The question is... Is it Worth it to buy this flash for this kind of travel?
I'd be inclined to skip the flash and bring a great tripod.
I spent ten days backpacking in New Mexico last year with a Canon 40D and 15-85mm, 50mm, and 70-300mm lenses. I brought a LumoPro LP160 flash, but left it at base camp, and I rarely missed it. Your T3i has a pop-up flash that is actually better than nothing at all. I used the flash on my 40D on a handful of occasions (below). In all cases, these were "fill flash" situations, and I think it's fair to say that these are shots to document the trip, rather than anything I'd expect to win awards.
If I were to entertain the thought of carrying a strobe, I'd personally be pretty strongly inclined to bring a set of remote triggers, too, because there were definitely cases where I'd have been able to use an off-camera flash. Just as I'm tempted to bring triggers, though, you'd have to consider whether you're going to bring extra batteries for the flash (maybe not a big deal if they double as spares for flashlights or something else), and other flash modifiers. The point is that it sort of opens the door to a whole other pile of stuff to haul around.
On the other hand, there's no way I'd leave home without some sort of tripod. I brought a Trekpod, which ultimately bought the farm somewhere along the way, but you could consider other options, too, including something like a GorillaPod. Just be sure you've got a way to steady your camera for long exposures -- I have a feeling you'll find that at least as valuable as a flash.
As always, this kind of questions depends on what you plan to photograph. If we are talking about the deep-blue sea, palms along the sandy beach, Thai temples and street traffic, then, probably, you will not need a flash.
If you are going to take pictures of people - street traders, monks, life saviors on the beach- if you are planning to enter low-ceiling houses of the locals, perhaps talk them into a "folk" scene, then a flash would come in handy.
Flash could also be useful if you decide to photograph local food. Anywhere where you go with bad lighting and close-up shots, you might need a flash.
Me personally, I am a landscape photographer. I have not needed a flash in the past 5 years, since I always stick to nature and urban architecture. People appear in my photographs so rarely that even if I made one or two photos during a trip, the flash would definitely not have been worth the fuss.
The first thing i'd say is that its pretty sunny there, generally speaking. If your outdoors during the day, chances are low you'll need a flash at all. In June normally all Thailand except the southern Gulf is in monsoon. The southern Gulf's (Samui and neighbours plus adjacent mainland coast) usual wet season is Oct into Jan. I can't speak for what the day light is like during that time however.
The recommended range for the flash isn't more than about 100mm, past that, its usefulness is limited. Using the integrated diffusion panel allows extended wide-angle coverage to 14mm.
It wouldn't hurt to have a better flash than the integrated one but it all depends on what you'll be shooting. With the 15-55mm lens i'd expect the integrated flash to do good enough.
It really depends on what you'll be shooting and what you'll be using the flash for. I used a couple of generic hand-held flashes for light painting in caves in Thailand. I thoroughly recommend them for this purpose!
Check out the DPreview link here for details about the flash and base your recommendations around that.
Hope that helps!
PS: Interstingly, I just came back from Thailand. All my camera gear got destroyed cause my peli-case leaked -_- Watch out for the water!
The answer, as usual, is "it depends". It depends on what kind of shots you hope to get, and how you plan to use your camera. Flash is beneficial for shots where there is not enough ambient light and the area to be lit is fairly small. It is also very useful when you need fill or to overcome extremely backlit subjects, such as when you must face the sun or a very bright window.
Flash can be useful indoors, in churches, museums and other such places. However, a flash will do very little to light an entire church, but might be useful for a statue or a few elements of detail you wish to capture. However, many places forbid flashes, as the cumulative light damages artifacts and artwork. So, instead of a flash for indoor travel photography, you would be better off with a tripod, and simply setting the camera on a slower shutter speed to capture your subject.
For fill light, a flash is really useful. Luckily, you have a built-in flash on your t3i, and this works reasonably well for fill. However, it is likely that the 55-250 lens might be long enough to block some of the flash. The 430EX will provide more light, and throw it further than your on-board, and it is positioned higher, so it will likely clear the lens. It also offers a separate focus light, that really aids in getting focus in low light situations. But frankly, a pocket flashlight, shining on your subject during focus does the same. For fill light, a reflector is a must have, but any white object for reflecting works well in a pinch: t-shirt, magazine, piece of paper.
So, my recommendation is that for travel photography, forget the flash. Buy a tripod instead, put a small flashlight in your pocket, and carry something to use as a reflector.
I have occasionally brought a flash hiking, but its purpose was for macro shots. Otherwise, I don't see a flash as having much use for hiking. If you don't plan on macro shots, like bugs, small flowers, mushrooms, etc, then a flash is probably not worthwhile.
Other nature shots, like landscapes and wildlife, don't make sense with a flash. For landscapes, the subject is far away by definition, so any amount of light you can create near the camera will be irrelevant and will actually hurt by lighting up dust in the air between you and the subject. Wildlife is difficult to get close enough to where a flash can help, and it is probably during the day when there is a lot of light anyway. Also, flashes tend to scare or annoy wildlife, with both results being undesirable. I saw this go comically wrong once for some moron that thought it was a good idea to get into the face of something 10 times his size and light off a flash straight into its eyes (moose was being tolerant up to then, decided he'd had enough, faked a charge, moron and camera went flying in different directions but both ended up in the same puddle).
So that pretty much leaves macro. There is a lot of interesting nature at the near microscopic level that most people overlook. Unfortunately physics is against you in this case. At 1:1 magnification you are already 2 f-stops down from what the aperture would otherwise tell you at normal high reduction ratios. Added to that, even tiny camera movements become visible, so you need a lot of light to get both depth of field and fast shutter speed. A flash on a extension cord can be a good solution. Hold the flash near the front of the lens. That makes the surface large compared to the subject, thereby providing a diffuse light effect contrary to normal single flashes. The close distance also compensates for the light lost in magnification.
If you're not going to bring a extension cord for the flash, then I wouldn't bother with it at all. I have used on-camera flash a few times, but those were all long in the past when I was using ISO 64 film. Nowadays you can have 4-5 f-stops advantage over ISO 64 film, so the usefulness of flash is greatly reduced. If I had ISO 1600 film back then, I wouldn't have used flash in the few cases I did 30 years ago.
