Hi guys,
I'm trying to take my first steps into manual focus with my 550D. I only have the kit lens at the moment, and I'm wondering what lens would be a good buy.
I'm looking for something that would give me more freedom for focusing ou medium distance subjects while keeping the background out of focus.
A crappy test pic I took yesterday with the kit lens trying to keep the lamp post focused:
In order to achieve that background blur (bokeh) you want, you need to have some distance between your subject and the background. In addition, having a tighter lens (more zoomed) will achieve better bokeh. A faster lens (larger aperture) will produce better bokeh. Finally, you want a lens with inherently good bokeh characteristics, usually due to things like number of aperture blades.
With your kit lens, try zooming all the way to the 55mm end of the lens (or 50mm would do ok), and make sure your subject is quite a bit closer than the background.
For manual focusing, I'd recommend using the live view mode, as you'll be able to see the focus and composition much better than through the viewfinder. Doesn't look like you quite achieved focus on your flagpole. The EF-S and EF lenses should provide focus confirmation as well, lighting up the auto-focus points in your viewfinder when you achieved proper manual focus on a given point. You have to hold the shutter release down half way (as if auto-focusing) for this feedback. Give it a try.
As far as other lenses that have nice bokeh, there's a lot of them. Usually, you want fast lenses (really low f/#, such as f/1.4), and lenses with some reach (50mm and up). The EF 85mm is a pretty well loved lens, coming in a variety of apertures. The 50mm f/1.4 is generally liked as well. Those might be good starting points. I use an old SMC Takumar 50mm 1.4 lens for my portrait work or pics I need good bokeh. You can find those for <$200 and all you need is an adapter.