I bought the Canon 700D recently and I'm really happy with it. Long exposure works just fine but for my purposes and just for experimenting I want to take very long exposures at low ISO for several minutes and see how they turn out.
The minimum shutter speed is 30 seconds and then there is Bulb. But with Bulb I have to press down the shutter button for as long as I want the camera to take the picture. Is there any way to make the camera take a very long exposure in bulb mode without having to hold down the button or do I have to buy a wireless remote?
You can, for very little money, build your own wired remote control, eg. by following these instructions, or any others that a google search for "canon diy remote" brings up. This remote has a momentary action switch, and a two way switch for arbitrarily long exposures.
I successfully made such a remote with my own two left hands.
You don't need to buy a wireless remote — you can buy a wired remote. For just a trigger button with a lock (to hold the button down), you can find 3rd party wired shutter releases for under $10 US, such as from Vivitar, Pixel, Vello, and other brands.
Yea... you can check out ebay or any local shop that sells camera equipment. You get wired remotes with a display screen that lets u take extremely long exposures (ranging from few seconds to 99 hours). These are best for exposures. Specially long ones. I take milky way shots so i use this remote to avoid any shake in my images.
While for long exposures is not that a problem, still you don't want to ruin a 10 minutes shot by accidentally moving the camera while pushing the button again to end the exposition. So, instead of messing with the button itself, your camera has a nice IR receiver that doesn't request you to buy an IR Remote at all if your smartphone happens to have IR feature!
Seriously...if your cellphone has an IR emitter, you can find apps on Play Store to control the 700D. I have a Pentax and use DSLR remote, for example, and works a charm.