Thanks to manufacture websites and sites like www.photozone.de, we are aware that both lenses have similar MTF figures. As much as I like to drool over MTF charts, I still like seeing real life samples and decided to run my own tests. I took both lenses out for a spin looking for their strengths and weaknesses.
The photos below are screen captures from Lightroom 3.4.1 (LR) and have not been processed, they are raw files as interpreted by Adobe. Keep an eye on the Loupe info to see which lens is which because I was not paying attention at the time of the screen captures, but LR flipped the lenses from left to right a few times. Below each image, I will post what I was testing for and let you decide which performed better. I will reserve my observations until the conclusion.
DISCLOSURE: I am not a professional tester, nor do I aspire to be one. I did this test for my own personal knowledge and my friend suggested I share my results for others interested in seeing actual side-by-side comparisons.
Click on images for undistorted views
Above Image: Same image as before, here I am showing the center of the frame. Of course this was shot on a tripod, focusing was done in Live View, 10-second timer and exposure delay was used to eliminate mirror shake.
My 50mm 1.4G observations
1.) When shooting equally fast apertures 1.8 – 2.8 it appears a bit brighter due to having less vignetting
2.) Better at controlling CA’s on strongly back-lit objects
3.) It is 2/3 of a stop faster
4.) Very slight advantage in Bokeh, although not as much as one would think, people assume that the absence of an aspherical element and two extra aperture blades should give the 1.4G a huge advantage over the 1.8G. That was not the case.
My 50mm 1.8G observations
1.) Is sharper at every aperture
2.) More contrast wide open
3.) Better control of flare and ghosting
4.) Less Coma
5.) Much cheaper
6.) Surprisingly smoother manual focusing feel