The subject distance is approximately 15-18 feet. As you can see, at this distance, these lenses are VERY close in resolving power and contrast at the center of the frame. Overall, assessing all the test images I've taken, considering the varying subject distances, the EX is slightly sharper at or around wide open apertures at the center of the frame; the L is the stronger performer at the borders. The EX is more consistently sharp especially at CLOSE distances at f1.4-f2.8. But the bottom line is that these are two sharp primes and both are VERY useable even wide open. The EX is phenomenal considering its small price tag ($359).

JUDGMENT: If you have a 1.6x body and are looking for a standard prime, look no further than the Sigma 30 EX. It is AT THE VERY LEAST EQUAL to the L optically, IF NOT BETTER (e.g., center resolving power, contrast, flare, color fringing). Unless you must have "L", there is no reason to choose the Canon (in this case) over the Sigma. For $359 USD (32% of the L), it is not only a "steal" but also one of Sigma's finest lenses in their stall. They could sell this lens for quite a bit more and it would still be worth it. Its build is very solid, it offers ring HSM (slightly inferior to Canon's USM) with full-time manual focusing, its optics top-class (border performance could be improved however), it has "significantly" better flare and CA performance than the L, and its size is fantastically SMALL. Sigma doesn't know what they're doing with all their non-HSM standard zooms, but they thought through this f1.4 prime real well. And while there are some focus issues with this lens (the 35L not excluded), Sigma can remedy the problem if need be --- they did with mine over a year ago. As for the 35L, what can be said at this point. Well, it's classic "L" built, it's got the red-ring, the fantastic Canon ring USM and FTM, the focus ring is dampened a bit smoother than the EX (which, at least with mine, is a little "gritty"), has a closer MFD and higher magnification, and its optics similarly impressive (better border performance than the Sigma, though not unexpected being a FF lens). But the EX being 32% the cost of the L, it stands to reason that for APS-C shooters, the Sigma fits the bill. If I thought the L was the "better" lens for 1.6x, I'd own it. Nonetheless, these are two GREAT lenses and you'd do well with one of them in your bag.