October 12th, 2023

Testing the Kipon M645 to GFX smart adapter

Addendum: Nov. 4, 2023 (at the end)

I just got the new Kipon Mamiya 645 lens to GFX smart adapter in the U.S. Mail from their U.S. distributor in Washington State, 6 days after ordering it.  Unfortunately the Focal Length metadata situation is royally screwed up.  The expected failure condition was that the adapter wouldn’t report a focal length value of the 75-150 D lens at all, mirroring the situation with dumb lenses and dumb adapters, and thus I would still have to go into the “Mount Adapter Setting” menu and manually select both the lens and the FL every time the lens was put on the camera or the focal length of the zoom changed, if either of those choices had previously been adjusted to something different when I last used an adapted lens.

So although the adapter is allowing the aperture to be set from the camera, the adapter’s behavior is much worse than merely failing to report the FL at all: it’s reporting 130mm all the time, regardless of the actual focal length set on the lens barrel and there’s no way to successfully override that 130mm setting in the “Mount Adapter Setting” feature — I can set a focal length there, but it is neither used for IBIS nor recorded in the files!  As a result, the IBIS only works right at or near 130mm.  Therefore the entire hand-holding capability for this lens is actually worse than that of my other adapted lenses connected via the much cheaper dumb adapter that I already had.  This is the worst of four or five problems with the adapter and a shocking disappointment.  Note that because both Mamiya and Pentax 645 autofocus type lenses don't have autofocus motors in the lenses, it's impossible for AF to operate when they're adapted to a GFX camera.  This also rules out the focus stacking capture features of the camera when using such lenses — it's native lenses only for that (but not the native T/S lenses).

The fit of the adapter on both ends feels approximately OK, so my initial impression was that both are good, and I haven’t yet noticed any swing or tilt focus shifting in the adapter caused by its two faces being out of parallel with one another showing up in test images.  So this important aspect seems OK too at first blush.

Later, I noticed that the fit of the 75-150 D lens into the adapter is distinctly looser than the fit of the same lens into my Kipon M645 to GFX dumb adapter, which is, if anything, a little too tight.  I’s say the new adapter is a hair too loose, so that looking carefully at light coming sideways through the crack at the top of the adapter while intermittently applying approximately the level of torque that the lens itself applies by virtue of its weight while in use, I can see a gap widening and narrowing.  It’s well under the thickness of an ordinary sheet of paper at .004”.  I may try to measure it later, as 4 mils is 100 microns, and we don’t want to have tilt (or swing) errors over about 10 microns introduced if at all possible.  I’d say the fit is not quite ideal but pretty much usable as-is for fairly critical work.  Which is to say that some tilt and swing will be introduced (with the camera in horizontal and vertical positions, respectively), but not much.

Kipon’s sale on the adapter ended very shortly after I placed my order so it’s now unfortunately at $623, up from the 20% off, $498 introductory price (plus $30 shipping for a box of about a half pound).

Inspecting the combination of the 75-100 D plus smart adapter for internal reflections, I see that the fairly narrow throat of the adapter is reflecting considerably more light from just outside the field of view (looking at diffused, ceiling fluorescent light fixtures in the evening) than the lens itself does.  Trying the same examination of both the M645 105-210 C lens and the 75-100 D lens on the Kipon dumb adapter, the flare situation is far better, with the much larger throat of the adapter adding essentially zero flare to the system.  Another strike against the new adapter.

But there’s another problem, annoying but of little consequence:  If you set the aperture, shutter speed, and ISO combination progressively so that the image gets darker and darker, suddenly, usually at about 3.5 to 4 EV underexposed, the image you see in the EVF and LCD starts flickering horribly at what looks like at least 10 cycles per second but not as fast as 60 cps, with horizontal light-dark alternating bands moving or blinking rapidly.  It’s reminiscent of interference patterns one can see from flickering fluorescent lights but it happens with daylight and is quite dependent on reaching an exposure level threshold to occur or not occur.  The captured image is apparently unaffected, so this is unlikely to actually be much of a nuisance, but it does appear to be a failing of the Kipon firmware, as I’ve never seen this happen with native lenses.  It also occurs very briefly at other times, so it really looks like a glitch in the adapter.

The lens name is incorrectly recorded in the metadata as “Kipon M645 to GFX |” (an only slightly incorrect name for the adapter, not the lens), rather than the name of the lens that I’ve entered into the Mount Adapter Setting interface.  What it should be doing is reading the name of the lens from the lens itself and reporting that automatically, but maybe the lens doesn't know its own name.

All of my prior experience with lens adapters for the GFX system has been with dumb adapters (for both P645 and M645).  I did try a Kipon P645 adapter but it was grossly defective (ridiculously loose) and I had to return it for a refund and get a Fotodiox one instead.  Whenever a native lens is attached, the Mount Adapter Setting option in the menus is grayed out, only coming to life when the native lens is removed and conceivably also waiting until a dumb adapter is actually connected, though I doubt it.  With the Kipon smart adapter connected, the camera is instead in a twilight zone between those two normal situations, where the Mount Adapter Setting feature is not grayed out, and yet the camera is sending and receiving aperture data to and from the lens, suggesting the Mount Adapter Setting feature should be grayed out because a smart lens is attached.  And most importantly. as I said, the camera is receiving (and using) the incorrect focal length data.

Did Kipon choose to have their smart adapter report 130mm for some reason, for example, thinking that it might be an optimal compromise for IBIS performance, assuming only one focal length could be reported?  Are they unable to decode the focal length data coming from the lens, or unable to query the lens for that information?  Did they simply not bother to get this right before starting to ship the product, thinking they might fix it later with a firmware update instead?

I do have two older M645 lenses in hand which are both manual focus, dumb lenses.  When I put the 105-210 ULD C lens onto the Kipon smart adapter and make an exposure, I see that the adapter has reported a focal length of 1490.0mm in the metadata of the resulting file!  (the lens was set to 210mm but that couldn't matter)  What can explain both of these two wildly different, incorrect results?  At any rate, this nonsense is causing the IBIS behavior of this combination of the manual focus, dumb, Mamiya 645 lens and the Kipon smart adapter to be absolutely awful, regardless of whether I take a look at zoomed-in, hand-held image stability at 210, 140, 130, or 105mm.  All focal lengths of this manual focus lens work great with respect to IBIS when dumb-adapted, once the focal length is set correctly in the Mount Adapter Setting interface.  But with this adapter, the dumb lens is entirely unusable with IBIS.  Tripod only.

The IBIS behavior of the 75-150 D lens on the smart adapter is normal at or very near 130mm, and gets worse and worse the further from 130mm that the lens is set, thus it's worst at 75mm, but still not as bad as turning IBIS off entirely.  It feels like I might be getting as much as 2 stops of stabilization, rather than the usual 5 or so.  I find this unacceptable.

If Kipon has no intention of making the adapter work right, by having it actually decode Mamiya’s messages about focal length and reporting them properly to the camera, it will continue to be a tragic shortcoming of this otherwise fine (and rather expensive) adapter.  This is a mess and it greatly reduces the value of the adapter and seemingly for no good reason.

I will attempt to get a response from them on this matter.  I wanted this 75-150 D lens’ optical performance very much for how well and how reliably it can render fine details in a flat scene over an ideal range of focal lengths for my outfit.

Now I have to consider the distinct possibility that one of the older, Mamiya 645 75-150 C lenses (with manual aperture ring), used on the dumb M645 to GFX adapter ironically might actually be a better solution.  I'm not sure but I think the optics of these two lenses is not the same.  It might be, however.  The number of elements and groups (11 and 10) is reportedly the same, as is the filter diameter (77mm), but the appearance of the lenses from the front doesn’t match with respect to what one can see behind the front element, and I can’t find one peep regarding optical performance of the older C lens anywhere on the web despite lots of searching.  Still, it could be optically identical, just with different mounting solutions for the various elements.  And lenses designed for manual focus operation are also easier to employ for focus stacking captures than those designed for AF operation but operated manually, with much greater rotation required to make a given focus change.

I was really hoping this setup could provide the long end performance for the system that would feel right.  This 75-150 D lens was a real gem from my first medium format outfit which I'd regretted being unable to use on the GFX camera because of its lack of an aperture ring.  I suspect the adapter will be going back.


—Joseph Holmes


PS: Fifteen or more days after writing to Kipon at info@kipon.com multiple times with a variety of questions I have yet to receive a single response.  Their site clearly refers to "Returns & Exchanges".  How can either of those occur if they won't respond to contacts?  I'd also very much like to be able to get clarifications from them about their intentions for further development of the firmware of this adapter

PPS: (1st addendum, Nov. 4, 2023) After my fourth email to their customer support address and more than two weeks of waiting I got a brief reply from them with two important points.  First, the adapter was built for communication with only the Phase One-branded electronic lenses for the Mamiya 645 system (meaning AF lenses with electronic contacts with the words Phase One on the barrel).  Also it appears from the experiences of various users of the GetDPI forum that their lenses of that class are seeing correct reporting of both the lens ID (type and model) and the approximate focal length to the GFX camera, meaning close enough for IBIS to work reasonably well, though proper IBIS function has not been confirmed by them.  This is good news and suggests that Kipon's development efforts for at least that class of lens were correct and done as well as could be done.  But why wasn't it made more clear on their web page for the adapter that this is the case?  Note that focal lengths reported by my Mamiya 75-150 D lens are approximate and never closer than the closest whole multiple of 5mm.  At 75mm, my lens reported 85mm to one of the Mamiya or Phase One-branded camera bodies that I had for that system, which I owned between 2007 and about 2014.

The second thing that Kipon support brought up in the email was whether I would like to see the same support added to the adapter's firmware (F/W) for Mamiya-branded electronic lenses for the M645 camera series, and pointing out that the F/W is user-upgradeable via USB-C, as I was aware.  Needless to say I said "Yes!"  Note that the first update offered by them for this adapter is for version 1.09 and that this appears to be the first Kipon F/W updater ever that can run on Macs as well as PC's.  Progress!  Until such time as this update is accomplished, the adapter will be an expensive paper weight.​​​​​