A few words of warning about the 50mm 1.8 EF-II "with the hood on": the HOOD has been implicated in hundreds of incidents of what Canon refers to as "barrel separation". When the 50/1.8-II model is fitted with its lens hood, the pairing has a disconcerting habit of causing the lens to snap into TWO, large pieces, due to the exact way the lens fits, and the way the hood fits onto the lens...the hood does not bayonet onto the outer, front part of the barrel, but instead, as I recall, fits the threads of the inner, front "cell". As with many cheap lenses, the 50/1.8 uses front-portion or "front cell" focusing...and the lens is held together with, I have been told by reliable sources, what are called "pop rivets"....not screws, but pop rivets. Anybody who thinks this barrel separation issue is just me talking needs to do a quick Google search, or a Fred Miranda.com search on this plastic "wonder"...
I'm not making this up; 50/1.8 EF-II model lenses, when they swing on a camera body and hit a solid object, have a pretty good chance of snapping the lens into its two main groups, and causing what Canon refers to as "barrel separation." So...do be careful when using it with a hood. Anyway....on a 1.6x Canon body, the factory hood is actually almost useless; what you need and want is a SMALLER-outside diameter, RUBBER lens hood...with the lens's field of view cropped off so seriously on modern 1.6x Canon d-slr bodies, a cheap, soft-rubber, thread-on lens hood from a third party will 1) actually SHADE the front element more, because it has a narrower opening than the factory hood, which was designed 18 years back, in the film era. And 2) when shooting toward the sun, the 50 1.8 EF-II flares and ghosts like the cheap, econo-design lens that it actually is....big, frame-filling, green FLARE and diaphragm ghosts can fill the entire picture area....however, with a soft, squishable rubber lens hood, you can use your left hand to flatten out the lens hood, and create a very workable "sun-blocker" that works a LOT better than the factory lens shade. I owned a 50/1.8 EF-II which I called "Der Flaremeister". When shooting toward bright lights, it was one of the absolutely biggest POS lens designs in 50mm lenses made over the past 35-40 years. It had very,very poor performance when shot towards the light--worse than many zooms with 2 to 3 times more lens elements...it was worse than the Nikon Series E (E-conomy) 50mm f/1.8 lens designed 35 years ago...
I use a Mamiya RB-360 rubber lens hood on my Nikkor 70-200 VR zoom lens, and when shooting toward the direct sun, that "professional grade" lens ALSO FLARES and GHOSTS like a SOB...so, when I need to shoot in the evenings or mornings outdoors, I use the squishable rubber lens hood, and NOT the factory petal-style hard plastic lens shades. To be fair, the Tokina 28-80mm f 2.8 ATX-PRO was also another lens I referred to as "Der Flaremeister". Both sucked about equally.