Hi, im pretty new here and am still learning photography, i recently went on holiday(vacation) and i ran in to a few problems, firstly at the zoo i was getting my son and a rhino into focus at different distances, i never got the shot but what i learned is that the lens i used only had infinity view when it is fully unzoomed, which is pretty disappointing as i thought every lens had infinity view at any zoom?
I must be wrong.

Second problem, was that when i tried to do a slow shutter speed pic of a water fall the whole image was just one white sheet (over exposed)
I was on manual setting with auto iso and manual everything esle and no matter how hard i tried it would only turn out as a full white picture, i also tried turning the camera to TV mode which only let me adjust the the shutter speed, took the picture but it was still over exposed, but not as much as if the camera was on manual, some objects were viasble but not anywhere near a good qualituy picture, and the waterfall was totally unvisable/white, it was between a 1 to 3 sec shutter speed which i was using to capture the image.
What am I doing wrong?

And last question is, on video mode when the sun is bright in the lcd screen and its not viewable, what is the best way to get good focus of your video as its happened to me a few times, the sun was bright and im unable to see the lcd for the video as it does not record video through the view finder, im using the Canon 1100d and a 55-250 is lens.

Any help would be appreciated

Thanks Kev