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02-18-2021, 05:45 PM   #1
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Lens mount problem

Hello all,

So I have 2 modern wide angle lenses, a Laowa 15mm f4 (with aperture ring but no eletronic contacts, aperture lever or aperture guard- that little piece beside where the aperture lever would be) and an Irix 11mm f4 with electronic contacts but no aperture ring or aperture guard.

Anyway, I can mount the Laowa on an old Pentax KM and take photos with it but I can't mount it on the MZ-S or MZ6 (just the MZ30, crippled mount FTW). So my question is why can't it be mounted on the MZS but it can mount on the KM? The camera mount looks the same, I don't get it

02-18-2021, 06:13 PM - 1 Like   #2
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QuoteOriginally posted by JJ-eire Quote
Hello all,

So I have 2 modern wide angle lenses, a Laowa 15mm f4 (with aperture ring but no eletronic contacts, aperture lever or aperture guard- that little piece beside where the aperture lever would be) and an Irix 11mm f4 with electronic contacts but no aperture ring or aperture guard.

Anyway, I can mount the Laowa on an old Pentax KM and take photos with it but I can't mount it on the MZ-S or MZ6 (just the MZ30, crippled mount FTW). So my question is why can't it be mounted on the MZS but it can mount on the KM? The camera mount looks the same, I don't get it
It might be interference between something in the mirror box on the KM and the deep power contacts on the KAF2 and later lenses.

I have some power zoom lenses that I could check on my KX I don’t think I ever tried when I shot film since I used them with a PZ1
02-18-2021, 10:27 PM   #3
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It is probably the power zoom contacts in the mirror box. If the MZ30 is like my MZ50 it has a dummy mount for the contacts with no contacts at all. By KM do you mean the manual focus film SLR or the K-m DSLR? The KM has no contacts in the mirror box. The Laowa should mount on DSLRs with power zoom contacts - there may be differences though between the design of the contacts between the film cameras and DSLRs.

Can you post photos of the mount on the Laowa and the mirror box of the MZ-S/6?
02-19-2021, 12:10 AM   #4
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QuoteOriginally posted by JJ-eire Quote
Hello all,

Anyway, I can mount the Laowa on an old Pentax KM and take photos with it but I can't mount it on the MZ-S or MZ6 (just the MZ30, crippled mount FTW).
Don't you can mount the Laowa lens physically or just get proper exposure?

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02-19-2021, 05:28 AM - 1 Like   #5
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QuoteQuote:
Mount KAF2
https://www.pentaxforums.com/camerareviews/pentax-mz-s.html

QuoteQuote:
Mount KAF
https://www.pentaxforums.com/camerareviews/pentax-mz-6-mz-l-zx-l.html

QuoteQuote:
Mount
KAF with limitations (cannot use M and K lenses)
https://www.pentaxforums.com/camerareviews/pentax-mz-30-zx-30.html



Read more at: https://www.pentaxforums.com/camerareviews/pentax-mz-30-zx-30.html#ixzz6mv6uHRht

here is information on various Pentax camera mounts
perhaps it may help ?
QuoteQuote:
Camera Mount Variants-

K: The original Pentax bayonet mount. Allows for manual and Av exposure modes (if the camera body supports this). The lens communicates to the body how many stops the aperture ring is stopped down.

KF: K mount with electrical contacts for the smc Pentax-AF 35-70mm f/2.8 autofocus lens. The autofocus motor is built into the lens. This mount was soon discontinued. Next generation autofocus lenses (F, FA D FA, FA J, DA, DA L) do not provide autofocus with this mount.

KA: This mount allows for all exposure modes (P, Av, Tv and M). These modes are available to the extent the camera/lens combination supports it. This is like a K mount with electrical contacts, so that the camera can detect the largest aperture and the range of apertures of the lens.

KAF: Provides screw-drive autofocus and supports all exposure modes (P, Av, Tv and M) to the extent the camera/lens combination supports it. It is like a KA mount with a drive shaft for autofocus and with an additional electrical contact allowing the camera to read detailed information from the lens (focal length, actual f/stop, and more).

Crippled KAF: This is a KAF mount without the coupler which indicates how far the lens is stopped down.

KAF2: It's like a KAF mount with two extra power contacts. Provides autofocus (screw drive as well as in-lens autofocus motor) and all exposure modes (P, Av, Tv and M) to the extent the camera/lens combination supports it. This mount supports MTF program mode which sets priority on optimum sharpness of the lens. This mount can also support power zoom, but not all camera bodies with KAF2 mount actually do support power zoom. The power contacts power the motors built into certain lenses be that SDM or DC autofocus motors or power zoom motors.

Crippled KAF2: This is a KAF2 mount without the coupler which indicates how far the lens is stopped down.


Lens Mount Variants-

Besides the mates fitting the K through KAF2 mount variants mentioned above, lenses can also be fitted with one of the following variants:

KAF3: This is a crippled KAF2 mount without the autofocus drive shaft. Lenses with the KAF3 mount will only autofocus on camera bodies with support for in-lens focus motors.

KAF4: This is a KAF3 mount without an aperture stop down lever. Lenses with the KAF4 mount will only work on camera bodies that support electronic aperture control (cameras from 2013 and newer, except for the K-500).

Note that not all bodies with KAF2 mounts support all of the functions of a power zoom. Most bodies support just zooming and lens retraction, but not the advanced functions like zoom clipping, etc.

Regarding cameras with scene exposure modes: These modes are supported wherever support for P mode is indicated.
The Pentax K-mount Camera Lens Compatibility Chart

Last edited by aslyfox; 02-19-2021 at 05:35 AM.
02-19-2021, 08:51 AM   #6
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The lever circled in the photo above is the aperture settings linkage and will be present on all non-"crippled" bodies including the KM film SLR.
02-19-2021, 10:30 AM   #7
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One thing occurred to me, for the OP are you saying when you can’t mount the lens, that it does not mount at all, or it does not lock in place.

I just remembered something, didn’t think much of it at the time, but perhaps related.

My DA560 mounts but will not lock in place on my sigma Teleconverters, which contain the aperture couplings

02-19-2021, 11:18 AM - 1 Like   #8
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The Laowa 15/4 has a non-coupled K-mount (crippled two ways) similar to that used by K-mount bellows and other perspective control lenses where a physical linkage is not possible. As such, the only points for conflict would be physical interference between the lens rear and/or failure to engage the aperture ring position coupler on the non-crippled mount of the two incompatible bodies. (This is probably accomplished with at cutout or slot on the lens base at about 8:00 with the red dot at 12:00.) I was unable to find any photos online showing the rear of the lens in Pentax-K, but the Nikon F version (similar flange depth) shows no obvious points of potential conflict. That and MightyMike's extensive review of the lens on the K-3 should be an indicator of general compatibility with at least crippled KAF2 having power contacts. I doubt this problem is with the lens. Edit: I was wrong...the problem is with the lens, at least bodies with non-crippled mounts.

A few questions:
  • What is the condition of the coupler on the the MZ-S and MZ-6? (metal tab just inside the mount opening of the camera at about 2:00)
  • Do other crippled-mount lenses mount on those two cameras without issue?
  • Are you able to use the aperture ring on K, A, F, and FA lenses for Av and M modes with those two cameras?


Steve

Last edited by stevebrot; 03-08-2021 at 07:47 PM.
02-19-2021, 11:24 AM   #9
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as a follow up, i have checked my KX film body and can mount my FA28-105 power zoom which is a KAF2 mount. so there should be no issue mounting a KAF2 mount lens to the film KM (similar body)
02-19-2021, 03:11 PM   #10
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QuoteOriginally posted by Lowell Goudge Quote
as a follow up, i have checked my KX film body and can mount my FA28-105 power zoom which is a KAF2 mount. so there should be no issue mounting a KAF2 mount lens to the film KM (similar body)
Thank you for checking, when I insert the lens, it won't twist so it won't mount at all, I don't care about metering but I would like to be able to use it on all K-mount cameras, it is a K-mount after all in it's simplest form, so no aperture lever or contacts which surprises me because surely nothing should get in the way of mounting.
02-19-2021, 03:14 PM   #11
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QuoteOriginally posted by JJ-eire Quote
Thank you for checking, when I insert the lens, it won't twist so it won't mount at all, I don't care about metering but I would like to be able to use it on all K-mount cameras, it is a K-mount after all in it's simplest form, so no aperture lever or contacts which surprises me because surely nothing should get in the way of mounting.
Can you send pictures. I agree I like to consider all my stuff as a system. 3 film bodies, 5 digital bodies (crop and Ff) and 60 lenses
02-19-2021, 03:22 PM   #12
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QuoteOriginally posted by stevebrot Quote
The Laowa 15/4 has a non-coupled K-mount (crippled two ways) similar to that used by K-mount bellows and other perspective control lenses where a physical linkage is not possible. As such, the only points for conflict would be physical interference between the lens rear and/or failure to engage the aperture ring position coupler on the non-crippled mount of the two incompatible bodies. (This is probably accomplished with at cutout or slot on the lens base at about 8:00 with the red dot at 12:00.) I was unable to find any photos online showing the rear of the lens in Pentax-K, but the Nikon F version (similar flange depth) shows no obvious points of potential conflict. That and MightyMike's extensive review of the lens on the K-3 should be an indicator of general compatibility with at least crippled KAF2 having power contacts. I doubt this problem is with the lens.

A few questions:
  • What is the condition of the coupler on the the MZ-S and MZ-6? (metal tab just inside the mount opening of the camera at about 2:00)
  • Do other crippled-mount lenses mount on those two cameras without issue?
  • Are you able to use the aperture ring on K, A, F, and FA lenses for Av and M modes with those two cameras?


Steve
Hello Steve, thanks for answering.

I have all the cameras on the table, an MZS, KM (film), MZ6 and a (new) Super A.
From what I can see they all look physically the same (ignoring contacts). They are in good condition all 4.

I don't have the Irix 11mm with me now but it is a crippled mount too, it also couldn't be mounted on the MZ6.

I can use the aperture rings on these cameras. (the ones with contacts show aperture correctly).

I see nothing on the Laowa mount that could obstruct mounting, I confess that I may have been able to mount it on the KM because I forced it on (I was like a K-mount is a K-mount, therefore it should fit on and it did, with considerable effort) but the KM cost me €20 vs €250 for the MZS so that's why I ask the question for future reference.
02-19-2021, 03:52 PM   #13
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I have recently observed that both the IRIX 150mm macro and the Laowa 100mm macro mounts interfere with the aperture ring coupler (aperture simulator) circled above, because they don't have the slit for it, which even modern Pentax lenses like the DFA 28-105mm have. It's very little, but could be enough to push lens up on the 2-o'clock-position that the bayonet doesn't engage. I have removed it from a TC and extension ring to work with those lenses - not an option in the camera. You would need to modify the bayonet ring on the lens.
02-19-2021, 03:59 PM   #14
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QuoteOriginally posted by JensE Quote
because they don't have the slit for it
This is serious...

If they don't have that the slit, there is potential to damage the coupler on K-mount cameras that have it. What's more, if the coupler is not engaged, stop-down metering will not be accurate.


Steve

Last edited by stevebrot; 02-19-2021 at 04:11 PM.
02-19-2021, 04:12 PM - 1 Like   #15
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QuoteOriginally posted by stevebrot Quote
If they don't have that the slit, it will likely damage the coupler on K-mount cameras that have it. What's more, if the coupler is not engaged, metering will not be accurate.
Just carefully checked the Laowa 100mm on a Program A: It is the coupler, for which there is no space in the lens mount. The Laowa would meter correctly in the A-Setting on cameras that support it. Do you think it makes sense to contact Laowa and IRIX to point out the potential damage on classic cameras?
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