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06-06-2018, 08:23 AM   #16
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QuoteOriginally posted by gofour3 Quote
That's good to know! I had my doubts after reading the 165/4 LS manual.


Good work!

For sure there is quite a lot of collective knowledge and wisdom represented on the Forum! The knowledge seeking process does not always work this well, but did this time.

Now, another question: Can the 165mm LS also be made to work on the K-1? I have tried unsuccessfully to make it work using the same method that worked on the 645Z. However, I cannot make the LS shutter fire at all. I am not using the Pentax brand adapter, just a cheap Chinese version. This is actually more a matter of curiosity really as I have no real need to use the lens on the K-1.

Any thoughts?


06-06-2018, 09:21 AM   #17
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For the camera to fire the leaf shutter, it has to operate the stop-down lever properly. If the adapter operates the stop-down lever properly (and many do not), then you should be able to make it work, as long as the focal-plane shutter opens in the split second between when the leaf shutter closes and when it opens again. Even that can be messed up if the linkage has the wrong geometry or too much slack. But if the adapter has no stop-down linkage, then it will never fire the leaf shutter.

Rick "the control is entirely mechanical" Denney
06-08-2018, 03:16 PM   #18
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To add my observations: The 6x7 90 L/S appears to work on the 645D with the Pentax adapter using a shutter speed of 1/8th with the 90mm L/S switch set to 'U' (usual) - without taping the contacts. I tested this in daylight with the L/S set to 1/125 & 1/250 without flash attached - both exposures were consistent with the L/S firing at the right time & speed. I'm sure the flash would fire at the same time as this is controlled by the L/S sync port. As an aside, this confirms that my newly acquired, ancient L/S lens shutter is reasonably accurate (at least as these speeds).

K mount bodies are a different story - IIRC the Pentax 6x7 to K mount adapter doesn't stop down the aperture (I doubt any 3rd party ones do either).
07-28-2019, 12:17 AM   #19
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Perhaps, setting the camera at 1/4 or even 1/2 sec will produce better sync and brighter photos?

Regards Jakob


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