Mamiya 645 Super leaf shutter lens issue

The manual says you can use any focal plane shutter speed lower than 1/8 with the leaf shutter. Mine won't work at all at 1/8, it works some of the time at 1/4 and all of the time at 1 sec on the focal plane setting. Haven't tried 1/2 second. I don't have the power winder and cock the lens shutter manually. I just developed a roll where I shot three flash pictures outdoors (fill flash). One came out perfectly exposed, the other two were totally unexposed. Even the daylight didn't get through. It seems there is a time lag after the mirror drops and the focal plane shutter opens before the leaf shutter operates. The flash fired each and every time. Seems like the focal plane shutter opens, then closes sometimes before the leaf shutter and flash goes off. I have never got a photo that is partially blocked by the focal plane shutter. It is either perfect or blank. I can put an empty back on, open the lid and verify the whole thing works by seeing the flash through it all.

Would purchasing the power winder fix this problem, or is there a problem in the camera or the lens? All focal plane shots with this camera are perfect. I only need the leaf shutter for outside fill flash because the sync speed on the focal plane shutter is only 1/60.

I think you have a problem either in the camera, or the lens, or in the connection between the two.

Does the camera work dependably with a non leaf shutter lens? Do you have the opportunity to try the lens on a different body? Does the camera work well with the lens set to work as a non - leaf shutter lens (i.e. with the leaf shutter disabled, and depending solely on the focal plane shutter)?

If you don't want to just send the two for a service, I would try to answer these questions first.

Matt

It sounds like the LS has a bit of a lag. Does the lens have any kind of a warranty? Unless you have a warranty, if it works at 1/2 second (or even 1 second if that's what it takes), I would just use it at that speed and not worry to much about it. Since you're using the shutter in the lens, the camera shutter speed doesn't really matter (as long as it's open long enough for the LS to fire).

The camera and lens work perfectly in other modes. I also have another lens (non-leaf) that works perfectly. The only time I need this leaf shutter is for fill flash outdoors. Unfortunately I don't have another body to try the lens on. I bought both the camera and lens used from KEH last spring.

I just took the lens off the body, cocked it and fired it by moving the aperture pin. It is erratic about the delay. Sometimes it fires right away, sometimes it delays about a half second. Guess it needs some CLA. Any guess how much that will cost me?

Sometimes (not always) you can get rid of the shutter lag (or most of it) by 'excersizing' the shutter (rapidly cocking and firing it over and over) several times. I've had some luck doing that with a couple of large format lenses that had some shutter lag at low shutter speeds. I've also had a couple that it didn't help much. My 90mm LS lens for my Pentax 67 lags a bit sometimes when it's cold, but works perfectly at room temp.