After doing a lot of research, reading a lot of AP and looking at lens types I have fried the brain & confused myself to no end. Please correct the following
Canon lenses that are marked L & have a red ring indicate that they are quality lenses (This is important to me as I want to go to the canon 40D)
Lenses that have a focal length of less than 25mm are considered a wide lens. (Good for landscapes, portrait photography, groups of people etc.
The lower the f stops on the lens the bigger the aperture which lets in more light making it a faster lens.
Faster lenses allow low light photography & blurring of the background like portrait photography.
Fast lens are also good for longer focal lengths lens as it allows more light through the longer lens.
A prime lens is a lens that cannot zoom, however it is a faster lens letting on more light, has a higher optical quality & is generally cheaper than a zoom lens.
So what I have gathered so far is to choose a lens that has the lowest aperture (f/stop number) in the lens of the focal length series you require.
But how the hell do I know if the optical quality is good.
Is there a number for quality 1 to 10 or glass type?
What are the types? What good & what not?
I see many recommendations on lenses but do not understand why.
Can anyone explain & correct anything wrong that I have written so far.