[G&R]

Hi all,

This is my first post here and its not a happy one.

I have purchased an eBay Pentax. When attaching a lens it felt a little bit stiff and on closer inspection a deformation in the body mount was found. I have other K-mount cameras and was able to compare the body mounting with various lenses.

It looks to me as though the camera may have taken knock such that a mounted lens pulled on one side of the body mount. It is possible to press the bump down slightly, and the gap is big enough to slide paper in.

Who sells replacement KAF4 body mounts? How much do they cost, and is this a DIY fix?

[Adam]

KAF4 is a lens mount, not a body mount. It is actually simpler than any of the mounts found on Pentax DSLRs. Which camera do you have?

In most markets, retail parts are not available, so this will also depend. Basic repairs at a service center range from $200-300.

[G&R]

This is a K3-II.

Does it need to be done by a repair centre?

---------- Post added 02-08-21 at 02:21 AM ----------

I see on the chart the camera-side is actually Crippled KAF2 and not KAF4. Would the mount be the same part used on other Pentax DSLRs and easy to transplant from a donor such as a K100D?

[aslyfox]

K-3, K-3 II
K-50, K-70, K-S1, K-S2
Crippled KAF2. . .

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

_______________________________


possible businesses to consult re: repair

UK
John Pye Technical (Authorized to perform warranty service)
Johnsons Photopia Ltd (Ceased operations. Former authorized service center)
Harrow Technical (Film cameras and lenses) (back in business)
Luton Camera Repair Services Ltd. (can service digital)
A.M. Technical Services (London area, can service digital)
GRES (Surrey, 645 and more)
Don Clark Camera Repairs Ltd (Gloucestershire)
Asahi Photo (Middlesex, film and digital)

Read more at: Pentax Repair Facilities (Wordwide listing) - Page 9 - PentaxForums.com

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Last edited by aslyfox; 02-08-2021 at 04:14 AM.

[G&R]

Yes, I see now that features are being removed instead of added, and it is a cKAF2 mount.

This is not getting me any closer to a repair plan. Can I take swap the mounts between a K3-II and K100D, or do I need to send the camera away for repair? Or, should I just return to seller as incorrectly described?

[pepperberry farm]

Yes, I see now that features are being removed instead of added, and it is a cKAF2 mount.

This is not getting me any closer to a repair plan. Can I take swap the mounts between a K3-II and K100D, or do I need to send the camera away for repair? Or, should I just return to seller as incorrectly described?

if this is a recent purchase, I would return it for a refund....

[G&R]

if this is a recent purchase, I would return it for a refund....

Noted thanks.

Is the metal cover not the same across all 21st century Pentax cameras? I would like to know why its a bad idea to try swapping the bayonet part between a cheaper model such as K100D or *ist DL..

[kypfer]

I'd have reservations about attempting such a repair if there's any consideration of trying to claim a refund in the future.
Can the camera be used as it is, and if so are all functions working as expected? If you can't test the camera, there's no way of knowing what other defects may be hidden. The sort of impact that caused a deformed lens mount may well have left some other components mis-aligned or broken.
Having tried and potentially failed to achieve a satisfactory repair, the vendor may well be given sufficient reason to refuse a refund " 'cos it's been fiddled with! ".

Even if the mount from a donor camera appears to be the same externally, and possibly even fit, there's no way of knowing if any thicknesses or internal clearances are sufficiently different to cause possible focussing issues, if nothing else.
Good luck

[Not a Number]

The part number for the K-3 is #77760-A104 (or 77760-A0104) or simply A104 - mount ring. It should be interchangeable with almost all the K-mount DSLRs.

USCamera.com used to be able to order parts and resell them but it appears Ricoh has become even more restrictive on who they sell parts to. You may want to contact them on the off chance that they can still get the part.

If you do attempt a DIY repair be mindful of the spring loaded contacts and ring underneath with soldered ground wire. The springs and contacts are easily lost or can end up in the mirror box. The wire is easily broken off.

[jatrax]

Unless the price was extremely good I would return for refund. The camera is damaged and likely has been dropped with enough force to bend the mount plate. Any attempt by you at repair will void the ebay 'warranty' and ebay will not back your claim. And you have no way of knowing that the mount plate is the only issue, other things could be damaged as well. If the camera was sold as working it is not as described. Don't waste your time and money trying to fix someone else's broken camera.

[aaacb]

I'd expect more than just the mount got damaged if it was enough to pull the ring out of shape. Could be anything from stripped screw to cracked internal frame. Without opening you can't know, but I'd return it.

[deanklim]

I had a K-1 that was erratically losing contact, the camera had taken a tumble a couple years earlier and dislodged the lens mount plate, actually the metering pins ended up underneath the lens mounting ring. I replaced it with the one off my K-50 to see if the mount was warped. So yes, it will work. My problem was the force of the impact slightly stripped out a couple threads in the thread hole and it would loosen over time. Planned on sending it off to see if it could be rethreaded but it took a tumble off a dresser with the 150-450 attached and that finished off the mount by stripping out the rest of the screw holes.

[G&R]

Seller has been very helpful. They have confirmed a particularly heavy lens was paired with this camera, after which the screws needed tightening - this strikes me as plausible and consistent with the deformation shown below.

Image 1: Thin space between lens and body on one side - light bouncing from a screw in the face of the mount.



Image 2: Small gap between camera body and in the section of the bayonet socket that has no screws. There is no gap where there are screws.



---------- Post added 02-08-21 at 10:06 AM ----------

I had a K-1 that was erratically losing contact, the camera had taken a tumble a couple years earlier and dislodged the lens mount plate, actually the metering pins ended up underneath the lens mounting ring.

Do my images suggest something is also under this lens mounting ring? Can I push the misplaced thing out of the way?

---------- Post added 02-08-21 at 10:12 AM ----------

Can the camera be used as it is, and if so are all functions working as expected?

It can be used, and seems to work. Only thing I was unsure about was the video ignoring aperture and assuming f/11 (not read the manual yet).

How do I test if the light from the middle of the lens is hitting the middle of the sensor?

[jatrax]

Seller has been very helpful. They have confirmed a particularly heavy lens was paired with this camera, after which the screws needed tightening - this strikes me as plausible

It might be plausible. But I have had all manner of heavy lenses on my K-3II with no issues. In my experience if the mount plate is bent it was caused by either a drop or by the camera being swung rapidly with the front of the lens hitting something such as a tree. The impact causes the mount screws to pull out.

No matter how helpful the seller is this is not your problem and the seller has now admitted that there was an issue. Do yourself a big favor and return it as not as described. Even if you get it to work it is likely the screw holes are stripped and the problem will return.

[leekil]

Unless the price was extremely good I would return for refund. The camera is damaged and likely has been dropped with enough force to bend the mount plate.

If the price was extremely good, this may be the reason why. It seems not unlikely that it could have been the reason the seller was selling.