Originally posted by NecroticSoldier What is Bokeh? and... what does it mean by being soft at wide aperture settings? also... what does it mean if a lens is fast?
The term bokeh refers to the out of focus portion of a photo.
A lens shot wide open has a very short depth of field (distance in front of and behind focal point that is in focus;DOF). The closer you (physically) are to your subject, the more pronounced that will be. In addition to that statement, with a lens wide open, the Further away you are, the more difficult it will be to get perfect point focus. Also the larger the format (film/sensor size) the more control you will have over it. Most point and shoot cameras have a sensor the size of a pinky fingernail, if that. The result of that (in addition to other things) is that DOF is almost infinite. At least in the visible frame it is. Look for discussions or tutorials on Image Circle to gain a better understanding of format size vs DOF.
The LOOK of the bokeh is what makes some lenses more desirable to some than others. The above shots were taken with a Pentax K30mm f2.8 at f2.8. That lens isn't easy to come by and is typically kind of expensive so I'm not suggesting you run right out and buy one.
Being able to selectively blur the surroundings of your subject is what sometimes makes the subject pop, giving it a 3d kind of look. Some disagree but I happen to think this shot nicely demonstrates that. K10d, FA 43mm f1.9 @ f2.0
Simply put, Lens speed typically refers to the aperture (sort of). The lower the Aperture number the faster the lens. Your 50mm f2.0 lets in half the light wide open as a 50mm f1.4 lens would (which is twice as fast). These lenses have bigger glass, are often heavier and always more expensive but worth it to those looking to move beyond snapshot mode.
Originally posted by NecroticSoldier Oh okay! thank you! Will do ;P unless my school textbook already has some info on it....
It probably does. There's plenty of internet reading you can do as well instead of spending more money on a book. I'm not saying the exposure book is a bad investment but your text book probably covers a lot of the same material. And, you can read all about it on the internet until your eyes bleed. Google is your friend that will save you from needlessly spending money. That's my opinion anyway..