100mm f/2.0 or 135mm f/2.8 Softfocus lens

[omni]

Hi everyone. I've narrowed down my choices for the next lens to:
-Canon 100mm f/2.0
-Canon 135mm f/2.8 with SoftFocus
Im looking for a new lens to photograph in a wedding. My current lens is the 18-55mm kit lens. I'm leaning towards the 135mm lens because I like the effect of the softfocus, but does anyone have any suggestions between the two?

I almost forgot:
I'm using a Canon 550D body (t2i), so would the 135mm lens be compatible with it? From what I understand, it was used for film cameras.

[sybren]

I wouldn't use the softfocus lens. You can add the effect digitally afterwards, using any lens. But when you have a softfocus lens, you can not turn it off.

[omni]

This lens gives the ability to choose how strong the soft focus effect will be as well as if you want to use it or not.

[inkista]

Sybren, there's a setting on the lens and you can dial in the amount of spherical aberration you want. And no, you really can't duplicate what it does in post-processing completely, not without a ton of work. This isn't the same as just applying a Gaussian blur, like some folks think it is. And the amount of softness is controlled not only through the levels but also the aperture setting.

The reputation of the 135SF is that with the soft focus set to 0, it's as sharp as the 135L. It's just that it's a relatively antiquated '70s/'80s design, and it's f/2.8.

I'd say, of the two, I'd probably get the 135SF, because I love that focal length on crop, and the soft-focus feature really intrigues me, but the 100/2 is probably a better general-use lens, especially if you need better available light performance. It's shorter, which eases the 1/focal_length shutter speed limit, it's f/2 instead of f/2.8, and it's USM (which the 135SF isn't), which is going to help immensely when it comes to autofocus. It's also quite a bit smaller and less conspicuous, which can help with the candid stuff.

I don't think you can go wrong with either one, but you're probably going to get more bang for the buck with the 100/2.

And no, you won't have any issues with using either one on a crop-body camera. The dRebels can use both EF and EF-S lenses. It's when you go up to full frame with a 5DMkII that you have to watch out, because then EF-S lenses cannot be used.