dougpeterson
Workshop Member
This is very common. Many 500 series lenses have unclean sync signals as a result of wear/tear/deterioration/age. A good service shop can get them back in spec for you, but make sure to go through someone who understands digital backs. As you note, it's very possible to have a lens which can still reliably trigger a flash, but which is not reliably triggering a digital back. This is because a flash and a digital back require different levels of stringency on the cleanliness of the signal generated by the flash sync port. A flash will fire even if there is a whisper of a faint momentary signal from the sync port, while a digital back is looking for a signal which is strong and has a specific profile (i.e. the profile a healthy Hassy lens produces).I have 2 batteries, one purchased new, one presumably used. At one time I was having difficulties, the batteries were freshly charged and the temperature was around 65F. At other times the temp was closer to freezing, or below, when changing batteries for the "fresh" one helped. The problem seems to be more susceptible in mirror up mode.... If I was having trouble in mirror up mode, then switched to "regular" mode, the problem many times ( not always) immediately goes away.
I was using 2 lenses on the same body, the 80 and the 50. The 50 was having trouble considerably more often than the 80. Thus my suspicion that the 50 might need a synch tune-up. When I briefly tried a 120 lens I had problems. Could be that both the 50 and 120 need synch tune-up. All of these lenses were tested with a flash ( no digital back). All fired off the flash as you would expect.
I also have 2 different synch cords from camera to back. No difference when I changed the cable.
Note that I had an Aptus II-5 body and the Aptus 65 at the same time. The Aptus II did not have this issue. Same temp, same batteries, same camera, same synch cord, same lens. It seemed to work fine. I no longer have the Aptus II in my possession, so further testing is impossible on that body.
I did try to put the back on a Hasselblad 2003 body, which sometimes worked and other times ( limited testing) failed, but in the same way that I was having trouble with the 500 body.... thus my thought that it has more to do with timing ( gating) than battery issues.
I was told to try to squeeze the cable release slowly, fast, gently, etc. None of these had any consistent effect.
There are some stories that when changing lenses, you must shut down the back then change lens than turn the back on again to make it synch reliably. Any truth to this story?
I realize that the problem may be due to lens/shutter synch problems only to do with the lens, and nothing to do with the back. But I need to prove this in some way before I start to have lenses repaired. My testing should resolve which is at fault,,, the lenses, or back, or battery, or technique.
I will do some further testing this weekend, and will report back on my findings.
The (nearly) definitive test is whether the back and sync cable work reliably on any lens. If so, then the issue is lens specific, even if it means both your other lenses require service.