Nikon Nikkor 50mm F1.4 Ai vs Zeiss Loxia 50mm F2.0

When moving from Canon system to Sony earlier this year, I didn't know much about the fly-by-wire focusing system on lenses.  The first Sony lens I purchased was the Sony Zeiss 24-70 F4 lens, and I loved the lens except for the fly-by-wire focusing system.  Whenever I'm getting focus manually, I would get frustrated.  I did some research and discovered most Sony E-mount lenses are fly-by-wire.  So, I began looking up online for some manual focus lenses for my A7s and came across the Zeiss Loxia line.  All the reviews online were nothing but praise for both 50mm and 35mm lenses.  And almost all of the reviewers mentioned that the manual focusing is not so bad with the Sony's peaking feature.  I was totally convinced and purchased the Loxia 50mm for 2 reasons: 1) There are times when F4 isn't enough for the shot I want, 2) there are times when manual focusing is needed.  And everyone knows I fell in love with the lens immediately.  

Naturally, I became interested also in the 35mm, which is slightly more expensive than the 50mm.  I couldn't afford the lens at the moment and I couldn't justify such a heavy purchase, because at 35mm, I don't need such shallow depth of field anyway.  Then, I began to think, if I can work with manual-only focus and without image stabilization, why don't I go with vintage manual lenses and adapters? So, as an alternative to Loxia 35mm, I began to look for some Nikon manual lenses and was able to find tons of them on eBay in $100-$200 range.  I have been watching several listings on eBay and last weekend I purchased a Nikkor 35mm F2 Non-Ai for less than $130, and of course ordered an adapter (Vello) for $44 on Amazon.  

With Amazon's 1-day prime shipping, I got the adapter first yesterday, and lens is still in transit.  I had almost forgotten that I've always had Nikon Nikkor 50mm F1.4 Ai which my dad had been using with film camera long time ago.  Since I now have the Loxia 50mm, I have no use for the Nikkor 50mm, but with the new adapter I purchased, I decided to do some comparison test.  After the test, I'm just confused and depressed. You can check out the test results.  And as a videographer who only has to deal with 1920x1080 image size, slight difference in image quality is often unnoticeable.  All I can say from these results is that a little more contrast with Loxia, but can't really see difference in sharpness. Was I a fool to purchase the Loxia lens when I've always had the Nikkor 50mm? Of course there are some advantages with the Loxia, 1) automatic focus assistance (camera zooms in when focus ring is turned), 2) EXIF data giving me the F-stop, 3) and more stops between F-stops (1.4 / 2 / 2.8 ... for Nikkor vs. 2 / 2.2 / 2.5 / 2.8 ... for Loxia).  But are these worth the extra cost? I really can't answer and that's why I'm confused.  I'm not going to sell the Loxia 50 because of these differences and also just because I love the lens so much overall (plus, I got a good deal on eBay for the used lens), but now I can't go on to buy the Loxia 35 knowing that it's very hard to justify the cost.  

We'll see how the Non-Ai (supposedly not as sharp as Ai) 35mm does when I get it in 2 days.  Non-Ai was about $50 cheaper than Ai lens, and I didn't want to spend too much on the vintage lens.  

(Clicking below photo will take you to Flickr page, where you can download the original size)