I'm looking to buy a "nifty 50" for my APS-C Canon. I'm stuck between the Canon EF 50mm f/1.4 USM Lens and the Sigma 50mm f1.4 EX DG HSM. What are the significant differences between these lenses and how can I decide which is right for me?
Both lenses have their strengths and weaknesses, so there is no clear cut "better" lens between the two. Each person will need to weigh all of the factors and decide for themselves which are more and which are less significant.
Here's a basic rundown of the advantages and disadvantages for each lens:
Canon EF 50mm f/1.4
- Very good overall image quality. Sharper in the corners at wide apertures than the Sigma.
- Less expensive. It currently runs about $350 in the U.S.
- More consistent focus accuracy on Canon bodies.
- Susceptible to damage if the front of the lens is impacted while focused at short distances. For more, please see: Canon 50mm f1.4 no longer focuses reliably. This can be mostly avoided by always insuring the lens is at infinity focus when not being used.
Sigma 50mm f/1.4 EX DG
- Very good overall image quality. Slightly sharper in the center but noticeably softer in the corners at wide apertures than the Canon. Sometimes that look is more desirable, sometimes it is not.
- More expensive. It currently runs $500 in the U.S.
- Third party lenses can be a risk that they won't be fully compatible with future camera bodies.
- Has been widely reported to demonstrate highly inconsistent auto focus accuracy on even upper tier Canon bodies, especially in lower light at at wide apertures. Less of a factor on cropped APS-C bodies than full frame, but still a significant consideration.
The Sigma review was written later and includes direct comparisons between theses two lenses as well as the Canon EF 50mm f/1.8 II and the EF 50mm f/1.2 L.
For my own analysis of the major differences between the EF 50mm f/1.4 and EF 50mm f/1.8 II, please see this answer. In regards to the newer EF 50mm f/1.8 STM, a lot of the disadvantages of the older f/1.8 II have been addressed, but I'm not a big fan of the manual focus-by-wire system that all STM lenses employ.
I'd look at the Sigma if I were you, reviewers seem to like it at least. I had the Canon and was very unimpressed by it, both optically and build-quality-wise. I ended up selling it and getting the Canon 1.8 instead, for all practical purposes it is a solid as the 1.4 (the USM motor in the 1.4 is a fragile design and susceptible to damage from even a slight bump to the front of the lens), "good enough" for my purposes and dirt cheap, even though it does look like a plastic chew-toy for dogs. They have replaced the 1.8 with a new design recently of course, I can't comment on that one as I've never seen one in the flesh.