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08-12-2013, 02:29 PM   #16
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QuoteOriginally posted by Paul MaudDib Quote
There is no "signal", Pentax LS lenses are completely mechanical. The shutter actuation is tied into the aperture stop-down lever. When the camera stops down, the leaf shutter blades close, the main shutter opens, after a fixed delay the leaf shutter reopens for its exposure, the leaf shutter closes, and the main shutter closes after its exposure time has been complete. Depending on the precise model the leaf shutter may or may not reopen until you cock it again (the 6x7 90 LS reopens, the 6x7 165 LS supposedly doesn't).

The camera knows nothing about when the leaf shutter opens and closes and in fact doesn't even know there's a second shutter in the lens. You must set the FP shutter to open for longer than the leaf shutter (at least 1/8th second) or else you will cut the exposure short, and the metering is based on the camera setting, not the lens setting.

It might be possible to create an adapter that would simply hold the lens open, assuming you had adequate register distance and all that other jazz. Essentially what you are suggesting is a permanent bulb exposure, you might be able to attach the contacts to a logic analyzer, trigger a bulb exposure, and then build an adapter that just sends that signal without closing it. It would probably require power continuously to hold the aperture open.
Yeah, what I said in my second post. Camera triggers the leaf shutter.

Would be cheaper to buy into a new system unless you have a strong electronics background and have been laid off work with too much free time. Paying somebody to figure it out would cost too much. An electrical engineer consultant is going to charge out at $1500/day. It is defintely possible just how much are you willing to pay. Of special note if you buy Leica S2 then you can use both the Leica lenses and hasselblad lenses since they had the R&D money to develop an adapter that worked perfect.

I am still not sure why the original post needs it so bad. I use to take pictures of rock climbers and trail runners just using strobes on non-LS lenses. Mostly outdoor fill light and highlight lighting though.

Easiest way to make it work if you are desperate is to invest the 2k for the adapter buy the RB lens and manually trigger both shutters. Trigger bulb, then trigger Mamiya LS, then release bulb and hope you didn't go over 30 seconds on the bulb and that the focus was correct when you triggered as the LS has to be closed when you activate bulb. If we are talking about fast action the chance of focus being correct diminishes.

08-23-2013, 09:30 PM   #17
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Digging this back up, I was going to purchase the Pentax 645 75mm f2.8 LS lens to adapt to Nikon D600.

I cannot see any electronic connections from the back the of lens and since the LS is pure mechanical, would it be able to use on the DSLR body?
08-24-2013, 03:18 PM   #18
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QuoteOriginally posted by grev Quote
Digging this back up, I was going to purchase the Pentax 645 75mm f2.8 LS lens to adapt to Nikon D600.

I cannot see any electronic connections from the back the of lens and since the LS is pure mechanical, would it be able to use on the DSLR body?
As a standard lens yes, not using the leaf shutter though. And yes there are electrical connections but I have no idea what they are used for. If you are just looking for a 75mm lens for the Nikon then there are lots of other options; if you really want a Pentax 645 75mm lens for the Nikon then a non LS lens would be cheaper (they sell for like $100USD vs $300 for LS). It is quite a nice lens but I don't know how well it would hold up on the Nikon D800 from a resolution perspective. A really incredible lens for the price though.
08-24-2013, 05:41 PM   #19
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Oh yes, I was just wondering if it was fully mechanical leaf shutter, that was all. And I actually don't have the D800, not anymore anyway, switched to full mirrorless and enjoying the benefits of all of these great old lenses adapted onto my Sony NEX-7 with the Metabones Speedbooster.

Also I do have many of the ultra fast 35mm format lenses already and was just wondering if that could be done, that's all... somehow I think the Mamiya leaf shutter lenses would encounter the same type of problem...

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