I have a dozen or so standard lenses with focal lengths in the 50 to 55mm and there are five F1.4 lenses. Yes you can call me crazy.

Tested here are three Pentax, one Yashica, and one Canon. Details below:

Super Takumar 50mm f1.4 -- This lens has some fungus growth in the rear elements. This explains the dreamy quality in the wide open round. Some yellowing shows up in pictures. It adds a warm tone to pictures of people, which isn't bad. Cost: $10

Super-Multi-Coated Takumar 50mm F1.4 -- This is the all metal construction version of the super multi-coated series. The sharpness of this lens rivals the Canon EF 50mm F1.4. Some yellowing as the other Pentax lenses tested here. Cost: $40

Yashica Yashinon-DX 50mm F1.4 -- This is the heaviest of all the lenses tested here. All metal construction and feels almost as good as the Takumars. Very neutral colours. Slightly soft wide open, but quite acceptable. Cost: $20 with the Yashica Eletro TL camera.

SMC Takumar 50mm F1.4 -- This is the latest version of the screw mount from Pentax. Focusing ring is made of plastic. Has a small scratch on the front element, but you won't see any effects of it in the pictures. Cost: $30

Canon EF 50mm F1.4 -- My latest purchase. Construction and build quality wise, this lens is not even as good as the 40 year-old Takumar. It does not feel as nice either, but it auto focuses and is quick. No ring USM motor, but surely good enough. Very sharp wide open with neutral colours. Cost: $499

The biggest advantage of the Canon, other than autofocus, is that you can set the aperture in 1/3 stops, where as the Takumars, from F1.4 to F2.0 is one click, and 1/2 stops after that between major F-stops, but the Canon can be set at F1.6 and F1.8 between F1.4 and F2.0. The Yashica offers only full stops.

Note: I am only testing the centre of the image.

Please view the pictures at the original size to see the 100% crop.