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08-09-2016, 04:20 AM   #1
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Pentax K-70 has issues with Sigma lenses, just like K-1

Seen on the Sigma web site today!!

Use of Pentax mount SIGMA interchangeable lenses when attached to the ?Pentax K-70? - SIGMA CORPORATION

08-09-2016, 04:31 AM   #2
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hmm - sounds like a bad precedent. If this continues with new Pentax models maybe Sigma will drop Pentax support.

Not a good business model to keep paying repairs for new Pentax cameras. Perhaps Pentax is hoping that this is the case so they can sell more of their lenses

oopsy

cheers
08-09-2016, 05:23 AM   #3
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Oh dear. The K-70 body looks so similar to the K-S2... is the overhang different? I'm guessing it must be...
08-09-2016, 06:21 AM   #4
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Strange indeed. Didn't think it had a different overhang from the K-S2 , maybe the K-s2 has it too but no one noticed?

Let's see:




08-09-2016, 06:25 AM   #5
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Or maybe no one noticed a problem on the K-S2.

Compare camera dimensions side by side
08-09-2016, 07:33 AM   #6
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That's strange. I've been using K-70 with the Sigma 150-500 with no problems. I did visually check the clearance when I first fitted it due to the issues with the K1 and it didn't appear to be tight.
08-09-2016, 07:36 AM   #7
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The not all the lenses show problems. Luck of the draw.
08-09-2016, 09:15 AM - 1 Like   #8
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QuoteOriginally posted by freddyisaac Quote
hmm - sounds like a bad precedent. If this continues with new Pentax models maybe Sigma will drop Pentax support.

Not a good business model to keep paying repairs for new Pentax cameras. Perhaps Pentax is hoping that this is the case so they can sell more of their lenses

oopsy

cheers
Posts on this topic for the K-1 indicated that Sigma reverse engineered the mount instead of going through proper channels. Basically, they guessed at specs and missed. Unless you have other information, blaming this on Pentax appears incorrect.

08-09-2016, 10:35 AM   #9
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QuoteOriginally posted by Mistlefoot Quote
Posts on this topic for the K-1 indicated that Sigma reverse engineered the mount instead of going through proper channels. Basically, they guessed at specs and missed.
Yes... although the photo @D1N0 posted above shows that even Pentax's own 18-135 is cutting things pretty fine on the K-S2 (and presumably on the K-70)...
08-09-2016, 10:52 AM   #10
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I think is the opposite, Sigma lenses have issues with Pentax cameras....

I think Ricoh go for make the minimal size of cleareance to make the cameras smaller (both K1 and K70, possible new design too)
08-09-2016, 03:14 PM - 1 Like   #11
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QuoteOriginally posted by Mistlefoot Quote
Posts on this topic for the K-1 indicated that Sigma reverse engineered the mount instead of going through proper channels. Basically, they guessed at specs and missed. Unless you have other information, blaming this on Pentax appears incorrect.
Before the K-1, and now the K-70, Sigma lenses never had any clearance issues on any other known Pentax cameras, even FF cameras going back to the 80s and earlier. For whatever that's worth.

In the case of the K-1, people on here speculated that the body needed more overhang near the mount because of the FF sensor and larger viewfinder. But that wouldn't apply to the K-70. And like I said, pretty much all of the old "FF" film cameras also had ample space around the mount.

Anyway, it's not a big deal. Sigma is modifying the effected lenses for free, once again demonstrating awesome customer service.

Anybody on here thinking about taking the opportunity to bash Pentax or Sigma should probably go ahead and re-read the earlier K-1 thread, as that ground has already been well-covered, and fingers have already been pointed in every which direction.

Last edited by Edgar_in_Indy; 08-09-2016 at 03:24 PM.
08-09-2016, 04:44 PM - 1 Like   #12
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It's irritating that Pentax didn't check this beforehand as a courtesy. I put my 150-500 and 35mm Art in for the free mount replacement because of the K-1.


They of course owe Sigma no actual favours (as 'ecosystem partner' is a synonym for 'competitor') but the camera body owners have been retrospectively hurt again.
08-09-2016, 04:51 PM   #13
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QuoteOriginally posted by virusn3t Quote
I think Ricoh go for make the minimal size of cleareance to make the cameras smaller (both K1 and K70, possible new design too)
The proof for this one would be to attempt a mount of the Sigma lens on a legacy Pentax body. Clearances on many of those are VERY tight.


Steve
08-09-2016, 05:04 PM   #14
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QuoteOriginally posted by Edgar_in_Indy Quote
Sigma lenses never had any clearance issues on any other known Pentax cameras, even FF cameras going back to the 80s and earlier.
I can't say I know any different in that regard, except that lens body incompatibility with third-party lenses was fairly common in the late 60s through the early 1980s. Mirror interference was the most common issue, though body clearance was not unknown. The classic example would be the various T-mount catadioptric mirror lenses common in the late 1970s and 1980s.


Steve
08-09-2016, 07:29 PM   #15
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QuoteOriginally posted by stevebrot Quote
The proof for this one would be to attempt a mount of the Sigma lens on a legacy Pentax body. Clearances on many of those are VERY tight.
My wife and her dad go to a lot of local auctions and estate sales, and they frequently get collections of old camera gear, including many Pentax bodies and lenses. I keep or sell the good stuff, but most of it is fairly worthless and ends up going to Goodwill. A lot of the bodies they get are Pentax, so since this kerfuffle with the Sigma lenses on the K-1, I've been paying attention to the mount clearance on these older Pentax FF cameras. From what I've seen, the old bodies have gobs of room around the mount. I suppose it's possible there are some exceptions, but I have yet to see them.

Here's three bodies I just happen to have on hand right now: K1000 (1970's), SF1 (1980's), and ZX-5n (1990's).



As you can see, the K1000 has no overhang whatsoever, so you could mount a bazooka if it had a K-mount on the end. The other two have a very slight overhang, but there is still gobs of space around the mount. I have two of the offending Sigma lenses, the 85mm 1.4 and the 50-150mm f/2.8, and they both have a bunch of extra room around them on these bodies.
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