Canon 35mm F2 IS USM or Sigma 35mm 1.4 for street photography?

JSorel wrote:

Hey Thanks for the comments!

Still in doubt, though...

mu55 - thanks for the tip, I will certainly give it a try!

pentel - not sure what you mean... I will be shooting in the streets, handheld and without flash, and I would like to stop motion - no motion blur...

...should not be underestimated. I'm embedding the photo below to give a context to my thoughts on the matter:

Canon 5D + 24 / 1.4L @ f/5.6, 1/8, ISO 100

Note the EXIF -- f/5.6, 1/8. Such a shot, even at the relatively wide focal length of 24mm on FF would be much easier with IS than without.

Myself, I got the Sigma 35 / 1.4 over the Canon 35 / 2 IS because, in the end, I felt I'd have more use for f/1.4 and IS, as I like to shoot shallow DOFs, even at wider angles of view, and, as things have turned out, I've used f/1.4 far more often than I'd have wanted IS.

That said, if you want the deeper DOFs, as most street photographers do, then I'm thinking you'd be stopped down to at least f/2.8 and as much as f/5.6 much of the time, so the f/1.4 of the Sigma isn't going to help you one way or another. Of course, the IS wouldn't help you, either, if you didn't want motion blur. Then again, the following photo is at f/1.4:

Canon 6D + Sigma 35 / 1.4 @ f/1.4, 1/4000, ISO 100

So, depending on your focal distance and the size you display the photo, f/1.4 won't have a particularly narrow DOF.  On the other hand, f/1.4 is "only" a stop faster than f/2 -- is the noise differential (or DOF differential, for that matter) really so much that it makes that big of a deal?

It's a tough decision, for sure.  When I got the Sigma over the Canon, they were priced the same, so I chose the Sigma.  If the Canon had be 35% less expensive, I'd have gotten the Canon.  Truth be told, I want both. 

In my personal opinion, the Sigma 35 / 1.4 and Canon 35 / 2 IS are the two finest 35mm lenses for Canon FF, and you can't go wrong with either one.