I've just aquired a couple of FTb bodies. They work perfectly, but both make a very distinctive and springy "twang" sound at the end of the shutter sequence. I've determined that it is coming from the armature that opens the aperture. Is this normal for this camera? If so, I find it quite annoying and "cheap" sounding. I'm familiar with the Canon "squeek" but not the "twang".
It does sound 'cheap', but is perfectly normal, although some of the earlier models don't produce the sound quite as much as the later ones. It is caused by vibration of the coiled spring which keeps the aperture lever taut. The shutter is closed and the mirror down when the sound is heard so it has no effect on exposure.
