The amount of photography gear required on your travels depends entirely on the camera system you’re invested in. If you prefer to keep things light and compact with a point and shoot then you’re in for some good news. At the other end of the spectrum, there are the DSLR camera systems that require quite a bit more space. The compromise between the two are Micro 4/3 systems or something like the Fuji x100.
If you have access to a computer at any stage in your travels, then you can take fewer SD cards for your camera. Instead buy a high capacity flash drive or rugged portable hard drive to backup your photos each time you fill the card.
It’s not always possible to get access to a computer, so you might be tempted to buy the largest SD card possible. Generally it’s considered a bad idea since if that one card is lost or malfunctions then you lose all of your photos. If you store them on multiple smaller cards, you’ll only lose a fraction of your photos if the worst case scenario happens.
You’ll also want to store any full cards in a secure way. The memory card cases from Pelican offer a water-resistant seal and shock absorbing interior for up to 8 SD cards, more than enough for most requirements.
Regardless of your camera system, multiple batteries are vital. Two at the least is recommended, though more if possible. This allows you to take a few in your pocket so you can quickly change them as you go. It also makes sure you’ve always got a set that’s charged, or currently charging.
How you carry your gear is entirely personal preference since it depends on your camera. Something small and compact like the Lowepro Slingshot seems to be the go to choice for anyone carrying a DSLR system with them. Any smaller cameras are usually best kept around the neck or in a small case inside your backpack.
Since you’ll want to keep the weight down as much as possible, you’ll have to figure out the best way to cover as many focal lengths with as few lenses as possible. If you can only have one lens then arguably one of the best zoom ranges you can take is the Canon EF 24-105mm F4 L IS, it covers a wide variety of situations and needs. A more affordable option would be the Canon EF 28-135mm F3.5-5.6 IS.
Either of these lenses should cover most situations and it’s certainly recommended to carry a 50mm prime lens for those low light situations if they should arise. You can choose between the 1.8, 1.4 lenses based on price.
If you’re using a system that isn’t a DSLR then your lens choice is likely limited or none-existent, while that’s unfortunately the limitation of smaller systems, it does allow you to travel lighter and potentially take photos more often, in harder to reach places.
If you can manage without a tripod then it’ll save a lot of hassle taking it with you. For most photographers, a tripod is a luxury not a necessity; take a little longer making sure your shot is steady in your hands.
If you absolutely must take a tripod then you’ll want something light weight, this’ll be expensive since you’re going to be looking into carbon-fibre based tripods. Gitzo, Benro and Manfrotto all offer travel carbon-fibre tripods. To keep the price down, you might want to look into a monopod instead, or the aluminium based versions.