Originally posted by Pedrodelta Hello folks,
I wonder if any of you talented people can throw a light on my problem. I have a Vivitar Series 1 f2.5 macro lens which when mounted on either my K5 or Samsung GX10 and placed in the 'A' mode, neither camera will let me set an aperture wider than f4.5 but will go 5.6 6.7 8.0 9.5 11 13 16 19 22 27 & 32 no problem.
There does not appear to be any physical defects with the aperture linkage which opens an shuts quite freely, no obvious sticking aperture blades and the aperture appears to open as wide as it possibly can.
There is no problem either as far as my eyes can detect with infinity focus. I've cleaned both sides of the contacts on mount and so far I'm stumped!
Anyone any thoughts? Grateful thanks in advance...Pedro
I have the exact same lens and have no issue controlling the aperture on the camera via A mode.
Try this.
Set the DSLR to M mode then on the lens manually set it to f2.5, press green button to stop down, note the f speed then take a shot, now set the lens to f4.5 then press green button, note the fspeed, take a shot.
Does the camera change drastically the fspeed? check the two images does the prior look like it was shot open and the latter shot at 4.5? If yes then your A contact might have a problem communicating with your DSLR.
Do you you have another lens with A mode so you can test with your DSLR and see if it's not the contact on the camera?
I suspect your lens has problem with the A pin.