-Zimbo-ya im wondering about the constant aperture. like wat are the benefits of having a constant aperture. and why do people go with the constant aperture to film skiing.
a constant aperature just means that it has the ability to use its lowest f stop through the whole range of the zoom.
for example: canon 70-200 f4
the lens is able to utilize the lowest aperature of f4 throughout the entire zoom range. it can use f4 at 70mm and f4 at 200mm
this is much different than say a canon kit lens 18-55 F3.5-5.6
on this kit lens it has f3.5-5.6, what this means is that you cannot use its lowest f stop (3.5) throughout the whole zoom range. you are able to utilize it at say 18mm, but not at 55mm. if you zoom the lens to 55mm the lowest f stop that you can take advantage of is f5.6, The f stop is variable depending on the focal length you are trying to shoot at
hopefully this makes sense.
now pros and cons and why you would use it:
personally, I dont specifically choose lenses that can hold a constant aperature across the entire range, its more of a byproduct of what i actually want. i choose glass based on sharpness and image quality, as well as its low light ability. I find that lenses that have that constant aperature are also very sharp - i want that image quality, the fixed aperature is just a perk. typically (not always) having that variable f stop means cheaper glass that is softer and produces poorer image quality.
BUT just because a lens is not constant does not mean that it is not good glass. the canon 100-400 f4.5-5.6 is very nice glass (being L glass), even without the ability to keep its lowest aperature of 4.5 throughout the whole zoom range.
_______________________________
If I were you i would practice with your kit lens and try to understand the basics before i invested in anything else. you need to reach a plataeu on your current equipment (a place where you feel that it is inhibbiting you from taking that "next step") before you invest in new gear. Learn how to produce a decent image with what you have - then worry about better glass
having nice equipment does not make you a good videographer - Knowing how to use it properly does