Properly Using FD Lenses

I've got a few Canon FD Lenses (50mm 1.8, etc) that I'm using with my BMPCC. I've got a Fotasy FD-MFT converter. I know because the converter isn't electronic I can't control Iris from the camera. But even when I'm adjusting the F stop ring on the lens the brightness isn't changing in the picture. At this point I can't shoot outdoors because so bright.

Is this a result of a faulty lens, or is there something I'm not doing to control brightness? What's the right way to shoot with FD lenses?

Perhaps this discussion over on another forum might help.

Sounds like you are using the newer FD lenses with the bayonet mounting mechanism rather than the older breech-lock kind (with the chrome rings). It's the same mount but the newer ones usually require some additional lever to engage the aperture control - like the ON-OFF ring the metabones adapter has. Some bayonet FD's have a switch or lever in the back that will allow you to get around this problem but I think most do not.