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03-06-2017, 10:25 PM   #1
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Another Sigma to add to incompatibility :(

I found out the hard way that Sigma's 1.4x TC (the DG EX APO version) will also damage the crap out of the K1 if you try to mount it. I was out birding and was only half paying attention while I was attempting to mount it. It was only after I'd scratched it while attempting to mount it, that I realized it didn't fit due to the K1's body shape. Does anyone know if Sigma has released a fix to this issue? The TC isn't on the list of affected lenses (hence why I thought it'd fit), but I'm hoping that it'll qualify for whatever frankenstein part they come up with.

03-06-2017, 11:17 PM   #2
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I'd contact Sigma and ask. They have been up front with lens alterations so far
03-07-2017, 01:15 AM   #3
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I use this TC with my Sigma 100-300 f4 and after reading this post I took a look at my K-1. On my body, if I stare at it long enough, I think I can see a slight scratch, but it almost blends in with the texture of the body and I probably would not have noticed it if not for this post.
03-07-2017, 09:28 AM   #4
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QuoteOriginally posted by Kameko Quote
Does anyone know if Sigma has released a fix to this issue?
Which part of the TC contacts the camera? If it is the "step up" for the mount flange, Sigma may be able to help you.


Steve

03-07-2017, 09:40 AM   #5
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QuoteOriginally posted by stevebrot Quote
Which part of the TC contacts the camera? If it is the "step up" for the mount flange, Sigma may be able to help you.


Steve
It's the edge of the mount/exterior part of the TC body. I just spoke with Gentec (Canada's Sigma dealer) and they're unaware of this issue with the TC. They're contacting Sigma to get more info and to see if that was overlooked. Hopefully they'll be able to replace the mount on this as well.

This thread was more as a heads up for those who've yet to try the Sigma TC on the K1. I did a ton of searching beforehand and didn't find any threads about the two being incompatible.
03-07-2017, 10:12 AM   #6
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Well, what diameter has that TC's bayonet mount? Compare that to the various images posted last year of the 70-200/2.8's bayonet, for instance.
03-08-2017, 02:39 AM - 1 Like   #7
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QuoteOriginally posted by Kameko Quote
Does anyone know if Sigma has released a fix to this issue? The TC isn't on the list of affected lenses (hence why I thought it'd fit), but I'm hoping that it'll qualify for whatever frankenstein part they come up with.
Hi

I can well understand the frustration, It is a bummer alright.

But let me be perfectly frank that nobody should blame Sigma for the problem.
If Ricoh alter the clearance just above the mount years after Sigma manufactured
lenses successfully to fit Pentax cameras I would find it hard to blame Sigma for the dilemma.

If Sigma repairs the problem free of charge it is nothing less than good will they are extending
to their customers. Don't get to demanding toward Sigma in your request to have it fixed.
If anything, it may just strengthen their resolve to stay away from Pentax.

Cheers
03-08-2017, 11:18 AM   #8
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QuoteOriginally posted by Schraubstock Quote
Hi

I can well understand the frustration, It is a bummer alright.

But let me be perfectly frank that nobody should blame Sigma for the problem.
If Ricoh alter the clearance just above the mount years after Sigma manufactured
lenses successfully to fit Pentax cameras I would find it hard to blame Sigma for the dilemma.

If Sigma repairs the problem free of charge it is nothing less than good will they are extending
to their customers. Don't get to demanding toward Sigma in your request to have it fixed.
If anything, it may just strengthen their resolve to stay away from Pentax.

Cheers
My understanding is that the Sigma lenses with problems don't meet the published K mount spec. That's why Sigma is fixing the problem for free. It was just luck that these lenses worked on previous models.

I think it speaks well of Sigma as a company that they're fixing the problem but it was their mistake not Pentax's or anything Ricoh "altered".

03-08-2017, 11:42 AM   #9
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QuoteOriginally posted by Schraubstock Quote
Hi

I can well understand the frustration, It is a bummer alright.

But let me be perfectly frank that nobody should blame Sigma for the problem.
If Ricoh alter the clearance just above the mount years after Sigma manufactured
lenses successfully to fit Pentax cameras I would find it hard to blame Sigma for the dilemma.

If Sigma repairs the problem free of charge it is nothing less than good will they are extending
to their customers. Don't get to demanding toward Sigma in your request to have it fixed.
If anything, it may just strengthen their resolve to stay away from Pentax.

Cheers
You must misunderstand as I'm not frustrated, rather disappointed that I'm unable to use the TC as is. I don't see where I placed blame on any party and as said before, I posted this as a heads up so others may contact Sigma prior to attempting to mount their Sigma teleconverter to their K1. Had I found a thread stating "don't put your Sigma 1.4x teleconverter on the K1 because it won't fit", I would not have attempted to do so.

QuoteOriginally posted by JimS_256 Quote
My understanding is that the Sigma lenses with problems don't meet the published K mount spec. That's why Sigma is fixing the problem for free. It was just luck that these lenses worked on previous models.

I think it speaks well of Sigma as a company that they're fixing the problem but it was their mistake not Pentax's or anything Ricoh "altered".
I am hopeful that Sigma will also replace the mount on the teleconverter. As I said, Gentec (Sigma Canada's service centre) was unaware that the teleconverter was one of the incompatible lenses. Because it's not on the list, I have to wait for Gentec to hear back from Sigma to get the thumbs up to replace the mount.
03-08-2017, 12:35 PM   #10
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QuoteOriginally posted by Schraubstock Quote
Hi

I can well understand the frustration, It is a bummer alright.

But let me be perfectly frank that nobody should blame Sigma for the problem.
If Ricoh alter the clearance just above the mount years after Sigma manufactured
lenses successfully to fit Pentax cameras I would find it hard to blame Sigma for the dilemma.

If Sigma repairs the problem free of charge it is nothing less than good will they are extending
to their customers. Don't get to demanding toward Sigma in your request to have it fixed.
If anything, it may just strengthen their resolve to stay away from Pentax.

Cheers
Sigma reverse engineered the Pentax mount rather than paying Ricoh for a license. It's not Ricoh's responsibility to maintain some ambiguous tolerances that don't exist in the official mount specs.

So yes, I do think it's Sigma's fault, but they are handling it with more grace than I'd expect from a company these days, which is reassuring.
03-08-2017, 01:01 PM - 3 Likes   #11
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This brings back such sad memories.....
When I first heard of this monumental disaster ages ago, I inspected my K1 and thought I found nothing....but after waking in the middle of the night full of anxiety and fear, I got a high powered LED flashlight and a 10X magnifier and took another look. Yep, there was indeed a tiny scratch, almost unseen by the human eye and in no way affecting anything about the abilities of the K1. Yet, having such monstrous damage to my K1, I cried like a baby...for days. I had trouble sleeping....couldn't eat (Well,I did manage some bacon) ,,,,,didn't even want to get out of bed, just stay there and weep all day. Dark thoughts came upon me....could I go on in life?...should I even try?
Finally, out of desperation, I showed the massive defect to Mrs Rupert and asked her to buy me another pristine virgin K1 like this one was when she bought it for me. After she took a look and said I must be imagining things, and then slapped me silly, I seemed to get over it as fast as it all started.

Good luck and I hope you too are able to overcome this devastating experience!

Best Regards!
03-08-2017, 03:45 PM   #12
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QuoteOriginally posted by JimS_256 Quote
My understanding is that the Sigma lenses with problems don't meet the published K mount spec.
There is no published Pentax K-mount spec nor has the basic mount design ever been patented. There is a Soviet GOST specification with drawings for K-mount lenses intended to fit Zenit SLRs. The drawings are frequently provided when the subject of clearance comes up, but they have definite Russian origin. I currently have three Pentax K-mount cameras and none of the three is identical as far as mount details and one (Super Program) has very tight clearance with several of my lenses. The tightest (~0.5mm clearance) is the Tamron Adaptall-2 PKA adapter which was made to fit the Super Program. Go figure...


Steve

Last edited by stevebrot; 03-08-2017 at 04:04 PM.
03-08-2017, 04:02 PM   #13
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QuoteOriginally posted by lithedreamer Quote
Sigma reverse engineered the Pentax mount rather than paying Ricoh for a license.
Once again...the is no patented design to license and never has been. The basic K-mount was an open design from the beginning.


Steve

(...FWIW, US Patents on proprietary elements of the KAF2 variant would have expired in 2008...)
03-08-2017, 05:00 PM - 1 Like   #14
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Looking at the two Sigma lenses of mine that Sigma applied their fix to (Sigma 35 f1.4, 70-200 f2.8 HSM II), all it effectively involved was shimming the mount point of the lens to push it away from the body by about 1 or 2mm.

If Sigma aren't able to provide a fix themselves, it may be possible to arrange a fix DIY, perhaps by cannibalizing a broken lens or TC to use it's mount ring as a shim.

Personally, in the case of a TC that I probably would not use that often, I would just live with the issue. Maybe I'd put some tape over the points of the lens tube where it may scratch the K-1 body. Or put some tape over the area of the K-1 body where the lens hits to protect that area somewhat.

FWIW, we've had a long and heated discussion about this issue before on PF ... but I am one of those in the camp which believes that Pentax (almost uniquely when looking at other DSLR makers) have been cramping the area around the lens mount too much in recent years, particularly the area of the body directly above the lens mount ring. This has caused problems for a number of lenses and bodies - not just with the K-1.
03-08-2017, 11:45 PM - 1 Like   #15
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QuoteOriginally posted by JimS_256 Quote
...Sigma lenses with problems don't meet the published K mount spec
You seem to imply that you have seen Pentax's mount specifications. Perhaps you can give us further details on which you base your claim.

Waite a minute, the Sigma lens (or TC as in this case) has not grown in size suddenly overnight. If Sigma's Products did not touch Pentax camera bodies just above the top of the mount before the introduction of the K-1 then the only explanation is that there have been changes to the K-1 body.

When I compare the K-1 with previous models it is clear to me that this part of the body in question has changed (is different). If such K-Mount specs exist this then simply means Ricoh/Pentax did not adhere to their own (fictitious ?) mount specification. Mount specifications or not, it is Ricoh's prerogative to make changes as long as it does not interfere with any of their own lenses.

I still maintain it is not Sigmas fault.
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