09-21-2015 11:33 PM
It is always 30 minutes. it's not actually technical limitation -- it's a political limitation.
By World Trade Organization treaty, tariffs may be applied to products being imported and the tariff on "video" cameras is not the same as the tariff on a "photographic" camera. Since nearly all "photographic" cameras can record "video", the treaties on tariffs establish that as long as the camera cannot record video for more than 30 minutes (continuously) then it will not have the "video camera" tariff applied to it (which in some countries can be as much as 30%). So manufacturers set 30 minutes as the maximum recording time for video (actually 29 minuts 59 seconds) to avoid having to pay the additional tariff (which would increase the price to consumers.)
Some countries do not apply the tariff. But since the cameras are designed for world-wide distributio, cameras in every country have this limit.
If you need more than 30 minutes of "continuous" video, you would need a dedicated video camera / camcorder.
09-22-2015 10:11 AM
You must remember and keep in mind, a 70D (DSLR) is a still camera that does video. It is not a video camera.
However, what they do, they do very well.