So help me, I could not resist. Immaculate Canon FTb body arrived today. It is strange that The all black newer FD 50mm 1.8 lens I added did not seem to want to meter properly apperture-wise. I took a silver backed (older) lens off my Canon TX and metering worked fine. Anyone else have this issue or is it par for the course?
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The FTb uses full aperture which relies on using the lever that transmit the actual aperture ring value to the camera.
This lever needs to be calibrated and i've seen many "new FD" 50/1.8 lenses that are off calibration by about 1/2 stop. You can test this by placing the lens on a Canon New F-1. The f-stop on the viewfinder should match the f-stop on the aperture ring. If they are off, this can be calibrated by disassembling the lens from the mount side. There is an adjustable stopper that adjust the linear relationship between the aperture ring on the lens and the aperture lever at the back of the lens.
If this calibration is off then the meter will not obtain the real aperture value.
On the other hand you may already be aware that the FTb meter requires a 1.3V battery. Use a #675 hearing-aid cell, which has the same voltage.
The other calibration that sometimes might be wrong is the calibration of the iris blades. The iris (diaphragm) blades sit on an assembly that can be rotated by loosening the 3 screws that hold such assembly (they are usually glued so they don't move). Rotating this assembly you change the actual f-stop of the lens relative to the aperture ring. Usually this is calibrated using special gauges but another easy way of calibrating it is using a known-good camera and calibrating (rotating) the assembly so at f2.8, f5.6 and f11 (or 16) the stop-down metering value is the same as the open-aperture metering value. Again, this is most easily done with a Canon New F-1.
Mind you, the New FD 50/1.8 was a very cheap lens so perhaps the factory calibration wasn't very demanding to begin with. On the other hand it is amazing that such a cheapily made lens could perform so good.
Nikkor lenses in general don't suffer these problems at all. But Canon FD lenses have more charisma and are more lovable
