Why not get Canon 50mm f/1.8 II instead?


It is almost 4 times cheaper, so it will be waaay easier to convince your wife. The pros and cons:


1) you loose 2/3 of F-stop and build quality.


2) you gain a tool to convince wife 'see, how much difference there is with f/1.8 lens? Imagine how better it would be to have a good quality f/1.4 lens!


3) even if you don't succeed convincing your wife to get more expensive one, you still have f/1.8 lens!


4) ...and you may decide later on, that you would rather get Sigma 30mm f/1.4