The Minolta AF 1.4/50mm is - as well as current Sony version - a typical representative of the Minolta AF f1.4 lenses (along with the AF 1.4/35mm and the AF 1.4/85mm). These three lenses have quite different characteristics when compared to their f2 or f2.8 equivalents (AF 2/35mm, AF 2.8/50mm, and AF 2/100mm).

Using the 24MP-FF Sony alpha 900, the Minolta AF 1.4/50mm is very soft at f1.4. Surprisingly the detail resolution at f1.4 is good even in the extreme corners. Stopping down to f2.0 increases the centre contrast dramatically, while everything else still remains very soft. f4.0 is recommended for best center performance, and f5.6 for best over-all performance. f8 may slightly increase the outermost corners, but at the cost of slightly decreasing centre resoltion. From f11 on diffraction is more pronounced, but not critical at all.

The 100% crops shown below were taken with a Sony alpha 900, Firmware 1.
RAW files from the camera were developped using Photoshop (Camera Raw 4.6 beta). Sharpening was set to "50", radius to "0.5 point", and detail to "50". Vignetting control was set manually to "68" (f1.4), "40" (f2), "20" (f2.8) and "0" (f5.6). Color aberrations were not corrected! All other parameters were set automatically by Photoshop during the first conversion, and kept constant afterwards.

Using the the 12MP-FF Sony alpha 700, the entire APS-C sensor is perfectly sharp from f4 on, but f2.8 is sufficient for almost any shot. For me the 1.4/50mm became a perfect portrait lens when changing from analogue to APS-C digital sensors. At f1.4, the low contrast combined with excellent resolution and the shallow depth-of-field are very useful shooting good portraits. It's relatively short f=75mm equivalent focal length keeps me in contact with the person to be portraited. Finally the small size of both the lens and the a700 ensure that the emotional/personal contact between photographer and model is not disturbed by a rather big and distracting "professional machine" (taking portraits with the alpha 900 or the Dynax 9, vertical grip and 1.4/85mm is something totally different).

The 100% crops shown below were taken with a Sony alpha 700, Firmware 3.
JPEG's directly from the camera, no post-processing other than cropping. All parameters such as contrast, sharpening, ... set to "0" or "standard".

		Minolta AF 50mm/1.4 f1.4 Left: 100% crop (alpha 700, 12 MP) from the center of image Right: 100% crop (alpha 700, 12 MP) from the corner of image
		f2.0
		f2.8
		f4.0
		f5.6

The koma is very pronounced wide open, but no issue from 2.8 on.

	Minolta AF 50mm 1:1.4 (first generation 1985) f1.4 jpeg directly from the alpha 700 corner
	Minolta AF 50mm 1:1.4 (first generation 1985) f1.7 jpeg directly from the alpha 700 corner
	Minolta AF 50mm 1:1.4 (first generation 1985) f2.0 jpeg directly from the alpha 700 corner
	Minolta AF 50mm 1:1.4 (first generation 1985) f2.8 jpeg directly from the alpha 700 corner