Cool mate !
I did get confused about the T3 , T3i ( I have T2i , a cheapo 7d
)...... I do wish they would stick to some sensible way of naming the models !
Not too sure how the t3 performs at the higher iso , I'll have a look at that .
I can see how zooming in video is not that nice , unless for special effect ...
The thing with a zoom lens is that it covers a lot of focal lengths in one lens , so one price for a range of coverage .
A prime lens is only one fixed focal length , but "should" outperform a zoom lens (or perform the same and be cheaper) .
A summary ....
The longer the focal length , the bigger the subject appears in the image ....but .... if the focal length is too long you may not be able to get far enough away from the subject to fit them in the frame .
The higher the "F" number , the thinner the "depth of field" ..... EG a small/thin depth of field will blur a background close to the subject ... a large/thick depth of field will need the back ground to be further away from the subject to be blurred .
Now here are a couple of terms you might not be familiar with .....
Bokeh ....... this is the quality of the background blur .... not how much it is blurred , but the quality....
This is determined on the construction of the lens .... take a close look at movies and photos at the background blur ..... a Sh!te bokeh can be seen as hexagonal shapes in highlights ..especially lensflares ..... a good bokeh is very smooth perfect circular patters that meld together .
Might not seem important , but you would be amazed how much the human eye will be attracted by this , kinda ultimate movie look that is so overlooked by the budget cinematographer .
Fore-shortening ...
Now this is the way a lens distorts the image proportional to it's focal length ....
Might sound a bit confusing ....but ...... a short lens will distort the image in a certain way , a fisheye lens is the extreme of this ...have a look ..
Now a wide angle lens will have a similar effect (that is an extreme example) .
Have a play with your kit lens at the 18 mm and the 50mm , take the same photo twice ..move closer to fill the frame at 18mm ..move away at 50mm ...the point is to fill the frame with the subject .
Now look at the pictures on your pc .... quite different .
Wide angle flatters some subjects (makes buildings and cars look big) ...but ... stick that on a woman and she may kick you in your nuts (eg makes noses look big and faces pinched) ... so for close shots of a beautiful woman ... a longer lens from further away will be more flattering (eg over 100 mm as a rule of thumb , I prefer to get nearer 200 mm) .
Finally your camera is more than capable of taking some absolutely brilliant photos , gotta be worth a go and see