gideon_kok

Looking at the front of your D3200, at the 7:30 position there is a little angled switch on the edge of the lens mount. This gets pushed in by the aperture tab on your lens. If this does not engage the error message does not disappear and the shutter will not activate. Your tab end might be a bit rounded and not getting the switch in far enough, causing intermittent problems.

I have a D3200 and got caught the same way. Peter Hamm is correct. If auto ISO is on the manual controls will still appear to be changing ISO as you wish. The manually selected ISO will be displayed on the right hand side of your rear screen but "ISO-A" will flash in the middle. "ISO AUTO" will flash in the bottom of your viewfinder but there is no indication of what selection will be used as you fire the shutter.

A modern 50mm would need to be stopped down to a smaller aperture to give useful sharpness. The optical formula is not designed for close-up. You would need a set-up with a mechanical aperture control of sorts. Even then I am convinced the iq will not be as good as can be achieved with a good macro. If you will not need a macro lens rather consider a film scanner instead