[kvetcha]

Nuh, this has been discussed before, Kvetcha.


They can of course only convert a lens where there is already a Sigma version of it.

That is certainly disappointing. Guess I'd hoped the whole thing was a bit more modular than it is.

Thanks for setting me straight.

[Caat]

Not to mention Sigma said they will be supplying repair kits to resolve the problem. Yes, it means you have to wait for the fix but what else is new even in this so-called high tech society?

It's not like you cannot mount the Sigma lenses at all. And it's not like Ricoh changed things so you could not use any K-mount lens.

I agree. However, the slight ambiguity in the Sigma note may put some people off.

There is going to be significant lag in Sigma fixing these lenses however. I think it is great that they are offering obviously.

[Dave L]

. On the physical rubbing, there is nothing that can be done about that. It is what it is. When you purchased that Sigma lens, it fit just fine on your Pentax body, right? I'd have to check my paperwork, but I don't recall Sigma saying that any of their lenses are guaranteed to fit and function on all future Pentax bodies. Don't think the lawyers would ever let them say that.

The lenses are sold as lenses for [digital] SLR cameras with a Pentax lens mount and if they don't correctly fit digital cameras with a Pentax lens mount (without damaging the camera), they were mis-sold, as long as the camera concerned meets the lens-mount specifications (including any specified clearances etc.). Whether or not the camera model existed when the lens was sold is irrelevant.

If it doesn't fit correctly, the lens is not fit for purpose and not as described (UK law) or whatever the relevant legal wording is in other Countries. Unless Pentax themselves stepped outside the K-mount design specifications with the K-1, Sigma will have to modify or replace and pay for all their non-compatible lenses to be fixed. I am sure they will, and so they should, though initial complaints in the UK are against the seller, not Sigma (sellers would then have a claim against Sigma).

[BigMackCam]

The lenses are sold as lenses for [digital] SLR cameras with a Pentax lens mount and if they don't fit digital cameras with a Pentax lens mount, they were mis-sold, as ;long as the camera concerned
meets the lens-mount specifications (including any specified clearances etc.). Whether or not the camera model existed when the lens was sold is irrelevant.

If it doesn't fit correctly, the lens is not fit for purpose and not as described (UK law) or whatever the relevant legal wording is in other Countries. Unless Pentax themselves stepped outside the K-mount design specifications with the K-1, Sigma will have to modify or replace and pay for all their non-compatible lenses to be fixed.

The Sigma lenses implicated weren't mis-sold until the K-1 was released - that is *very* relevant. Sigma can't be held accountable for design changes in new camera models from any manufacturer, and the lens is sold as K-mount compatible. Any lenses sold *since* then as being K-mount compatible, but without notifying the buyer that they are not suitable for the K-1, could potentially be considered as mis-sold, and the retailer would be under an obligation to resolve the matter.

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Last edited by BigMackCam; 05-12-2016 at 04:18 AM.

[Dave L]

The Sigma lenses implicated weren't mis-sold until the K-1 was released - that is *very* relevant. Any lenses sold *since* then as being K-mount compatible, but without notifying the buyer that they are not suitable for the K-1, could be considered as mis-sold, and the retailer would be under an obligation to resolve the matter.

I'd say it's the other way round. K-mount Sigma lenses weren't sold as being compatible with specific K-mount cameras but implicitly with all K-mount cameras and buyers were entitled to think that would continue with future K-mount cameras (as long as the future cameras were within the mount specs.). So if K-1 is within spec and lenses sold were outside the spec. as it was when sold, it's ultimately Sigma's problem.

But if someone today buys a Sigma lens and the seller points out that it may not fit K-1 or will mark the body, it's the buyer's problem.

[BigMackCam]

I'd say it's the other way round. K-mount Sigma lenses weren't sold as being compatible with specific K-mount cameras but implicitly with all K-mount cameras and buyers were entitled to think that would continue with future K-mount cameras (as long as the future cameras were within the mount specs.). So if K-1 is within spec and lenses sold were outside spec, it's ultimately Sigma's problem.

But if someone today buys a Sigma lens and the seller points out that it may not fit K-1 or will mark the body, it's the buyer's problem.

Trust me, from a legal perspective, it only became an issue once the K-1 was released. You can't hold a manufacturer liable for incompatibility with future products that don't exist at the time of sale. I have an old film era Tokina lens for A-mount that won't work with newer Sony A-mount digital bodies, though the mount is the same. Tokina didn't mis-sell that lens and I can't go back to them claiming they are liable. It was sold as A-mount compatible, and - based on the cameras available at that time - it was.

[gaweidert]

In looking at the photo posted here, it looks like Sigma may not have paid too much attention to the run out of their mount. There is no real need to have any of the metal protruding beyond the edge of the metal on the camera mount. However It would not surprise me if that little edge measures a bit different on different lenses of the same model. Why take the time needed to machine a part more than absolutely needed. Hence some people are having the issue and some are not Until now it has not been a concern so why put a tight spec on it.

[monochrome]

The thing is, Pentax did leave room above the mount - more than the K-mount specification requires - but that isn't quite enough for a few lenses.

I'm empathetic with people who own the affected lenses, to a point, but it's rapidly moving toward TS.

Sigma made lenses outside spec
Pentax made a new camera inside spec
A few extremely non-compliant Sigma lenses are 1/10mm too big
Sigma is going to fix these lenses

That should end the discussion

[Dave L]

Trust me, from a legal perspective, it only became an issue once the K-1 was released. You can't hold a manufacturer liable for incompatibility with future products that don't exist at the time of sale. I have an old film era Tokina lens for A-mount that won't work with newer Sony A-mount digital bodies, though the mount is the same. Tokina didn't mis-sell that lens and I can't go back to them claiming they are liable. It was sold as A-mount compatible, and - based on the cameras available at that time - it was.

Yes but that's presumably because Sony changed the mount or enhanced it, so obviously older lenses won't work with the changed bits just as my Pentax M lenses won't fully work with any automatic or digital Pentax camera. They still fit the newer K-mount cameras though, and still do what they did when i bought them. If they could no longer even be mounted on a newer K-mount camera, that's something so basic that I'd have a claim... for a few years anyway (about 6 in the UK I think but it depends on how long they are expected to last).

If Sigma sold their lenses as being compatible with "all current digital K-mount cameras" things would be different, but they don't because they know that they'd sell fewer lenses if they did that.

[BigMackCam]

The thing is, Pentax did leave room above the mount - more than the K-mount specification requires - but that isn't quite enough for a few lenses.

I'm empathetic with people who own the affected lenses, to a point, but it's rapidly moving toward TS.

Pentax made a camera inside spec
Sigma made lenses outside spec
A few extremely non-compliant Sigma lenses are 1/10mm too big
Sigma is going to fix these lenses

That should end the discussion

Ah, that's interesting. So, if the lenses are outside the published K-mount spec as it existed at point of sale, that *would* make them potentially liable if the lenses were sold as K-mount compatible. Presumably this is why Sigma is to offer modification to make them K-1 compatible...

[RobA_Oz]

Indeed, and the agreement is so good that we can't buy most modern Tamron lenses in K-mount and pay a hefty premium for the equivalent rebadged Pentax version.

That's based on the assumption that Tokina and Tamron would have released those lenses in K-mount in their own right. Given the reality that Cosina/Voigtlander and Zeiss stopped releasing K-mount versions, and that Tamron and Sigma had previously reduced the range of their lenses that were available in K-mount, it's also not unreasonable to think it's possible that Ricoh's deal with Tamron was the only way those lenses were going to be available. When you combine the low numbers with special features like removing OIS and then changing lens coatings and remodelling bodies to suit, it shouldn't be a wonder that their pricing is higher. I really doubt the deal is designed just to make Pentax users pay more.

[pathdoc]

Has anybody tried mounting any of the Pentax K-mount bellows on the K-1 yet?

Not me, but the Asahi Pentax M42-era bellows is a scratch-tight fit on the K-5 because of the knob which tightens the bellows-to-camera mount onto the actual bellows assembly. K-1 users looking for a secondhand bellows would be well advised to go K mount rather than M42. I went M42 because I already had an M42/K adapter and plenty of Takumar lenses to put on it, and because I own and shoot Spotmatics anyway and it gives them macro capability.

[BigMackCam]

Yes but that's presumably because Sony changed the mount or enhanced it, so obviously older lenses won't work with the changed bits just as my Pentax M lenses won't fully work with any automatic or digital Pentax camera.

No, the Sony A-mount is still the same. It's camera firmware that the lens is now incompatible with. And if Ricoh had designed the K-1 such that your Pentax M lenses didn't work at all, you'd have no claim against them unless they advertised full compatibility with all previous Pentax K-mount lenses. But, that said, in my original reply to your post I hadn't realised what @monchrome stated - ie. that the Sigma lenses are outside the published K-mount specification. If that is the case, then Sigma has technically mis-sold their K-mount lenses as K-mount compatible. Sounds like Sigma is going to make good on the modifications, though, which is great news.

[Caat]

Does anyone know where the "K-mount Specification" is written down and exactly what it precisely covers?

[distudio]

Does anyone know where the "K-mount Specification" is written down and exactly what it precisely covers?

It's a crock anyway, they have screwed up in the past. The first Pentax body to implement that hideous prism overhang was the K10D from recollection.

That lovely bit of jutting plastic wouldn't allow the A*200/4 macro to rotate to portrait mode whilst the pair was mounted on the supplied tripod mount as the set screws on the mount collar collided with the prism overhang, they didn't offer to fix that. It also made using the aperture ring less than comfortable.