There is no FL mode for FD lenses. As long as the FD's aperture ring is not set at 0 or A you can use it in stop down mode the same way you would use an FL lens in stop down mode. It is an FL lens which must have its A/M switch set to A for proper stop down metering. The 35-105/3.5 New FD is a decent lens. What I don't like about it is that even at the 105 setting and at its closest focusing distance you are still too far away from the subject for a tightly cropped portrait. The way the "macro" setting on the lens works, it is not useful for portraits. I do not have the 28-85/4 New FD. It is supposed to be a good lens. Some other good lenses in this range include: 28-90/2.8-3.5 Vivitar Series 1, 28-85/2.8-3.8 Kiron, 28-85/2.8-3.8 Vivitar, 28-85/3.5-4.5Tokina AT-X, 28-85/3.5-4.5 Vivitar (Ser. # 77XXX...).