Test performed only with the Canon FD 50mm F1.4 lens.
It is a lens from 1978 (specifically the last model that went on sale), which was very popular due to its high quality and relatively low cost, which today is still easy to find second hand at a good price ( Between € 80-140). It is a very luminous lens and above all very sharp, in addition to very light (235g), with measures very contained 44 mm in length, by 61 mm in diameter. Open up to 1.4 and close up to f22. Its minimum focus is 45cm with respect to the subject. It has 8 blades that make up the lens diaphragm. The body is metallic and the control is completely manual, including the diaphragm.
It is a very comfortable and versatile lens, even to work with it on drones or light stabilizers. It offers very good results especially in terms of focus in the central area. If it is true that it loses some sharpness in the corners, especially in openings below f8, in addition to causing a slight distortion and vignetting. It is an ideal portrait lens, which can also be used comfortably for streetphoto, because of its small size.
Like many old lenses or other cheaper options of Chinese origin, it does not have anti-reflective varnishes on its lenses, which causes that it is very susceptible to receive all type of flares or other effects, being able to be reduced by means of a visor (lens hood BS- 52) that improves the contrast. The appearance of these reflections or flares can be an effect sought or not, so it should be taken into account when working with this lens of photography.
In my opinion, it is a highly recommended target in terms of price and results, and aesthetically very beautiful. What offers us a very economic alternative for Full Frame cameras without mirror (mirrorless or evil).