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Forum: Pentax K-1 & K-1 II
06-04-2016, 11:07 AM
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That was discussed in various threads in this forum. The offending lens, the 70-200/2.8 APO DG Macro II HSM, comes with two different LensID values. Both are listed on the exiftool website:
Pentax Tags
The presumably* older variant of that lens, which I happen to have purchased somewhen in 2010, is the one using the LensID value "8 255" (some other Sigma lenses use the same value and can be discerned only by analyzing some other values in combination).
As was pointed out by forum member stevebrot in this posting https://www.pentaxforums.com/forums/190-pentax-k-1/319686-k-1-3rd-party-lens-...ml#post3623304, the other variant uses the LensID value "8 16".
Forum member disasterfim states that there exists a firmware upgrade in this posting https://www.pentaxforums.com/forums/190-pentax-k-1/319686-k-1-3rd-party-lens-...ml#post3620715 and that that upgrade cured liveview AF problems with the combination of that lens and the K-5 IIs.
*) I presume that the problematic lens is the older edition, since I've bought mine in 2010 and it was discontinued somewhen in 2012
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Forum: Pentax K-1 & K-1 II
06-04-2016, 10:32 AM
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Have you checked the LensID reported by exiftool? You'll just need an image taken with some Pentax DSLR and the 70-200, and run the following command line with it:
Code:
exiftool -b -LensID yourimage.jpg (also works on .dng and .pef files)
If the result is "8 255", your lens needs a firmware upgrade, if it's "8 16", it does not and will work fine on the K-1.
The mechanical problem is not so severe that you'd be unabled to attach the lens, it just leaves a small scuff mark. Yes, that's something it shouldn't, but it's not severe damage to the camera, it's mostly a cosmetical problem.
Of course you might want to wait a while 'till you get yourself a copy of the K-1 - maybe it's price will drop (something I doubt for the foreseeable future due to the demand, which seems to be quite high).
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Forum: Pentax K-1 & K-1 II
06-04-2016, 03:05 AM
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Well, redundancy is what makes the internet tick ...
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Forum: Pentax K-1 & K-1 II
06-04-2016, 12:09 AM
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With the 70-200 there could be two problems. The mechanical problem of the lens' bayonet ring leaving a slight scratch or scuff mark on the K-1's body is real, and depending on the age of the lens there might be an additional software compatibility issue.
The older variants of this lens identify themselves with LensID "8 255" and cause the K-1 to freeze. They can't be used on the K-1 at all. Newer variants use LensID "8 16" and work fine.
You can check that using exiftool on images you took with your pre-K-1 camera.
According to other users, the older variant of the lens also caused problems with older bodies such as the K-5 and K-3, but not as severe as a complete camera lock-up. Here AF functionality in liveview mode was more or less inexistent.
There seems to be the possibility of Sigma updating the lens' firmware, and since the lens has to be sent in to Sigma anyway (due to the mechanical problem) they could fix that too.
[Update]
I've just found an updated statement from Sigma
https://www.sigma-foto.de/service/servicehinweise/aktuelle-serviceinfos/upda...er-pentax-k-1/
(the link itself is in german, but the content is in english)
where Sigma offers repair of scratched K-1 bodies:
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Forum: Pentax K-1 & K-1 II
06-03-2016, 10:17 AM
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I don't understand how a russian document could be the standard documentation of the K bayonet. That seems to be documentation of something similar and compatible to the K bayonet, but the guys who invented the K bayonet were working at Pentax, in Japan.
Never had Pentax any relation to the USSR Bureau of Standardization, so whatever they've documented there might well be naught more than the result of careful ... re-engineering.
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Forum: Pentax K-1 & K-1 II
05-13-2016, 11:47 PM
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No good idea, besides your mixup of millimetres and centimetres.
First, the offending ring is made from plated brass. Once the plating is removed (due to wear and tear or due to other mechanical reasons), the brass will be visible.
Second, except for the most adept file handlers, this will have some kind of 3rd-world-hack feeling. Ugly scratches and dents. Should you ever think about selling a lens that looks as if somebody held a file to it's bayonet ring - forget it.
Third, even with most careful application of masking tape, it's close to impossible to hinder small metal flakes to fall in places where they don't belong.
No, don't do this at home, and don't do this in your workshop, should you happen to have one.
A way to handle this would be removing the ring from the lens and fitting it to a lathe, but this would need some extra effort just to fix it precisely in plane. Your run-of-the-mill three-jaw chuck won't be the perfect tool for the job.
And even then, the first two points would still be valid - visible (and oxidizing brass) and a klunky "fumbled with in an inappropriate way"-feeling for a precision optical instrument.
Nah. Don't. Let's wait for details on what Sigma wants for replacing that ring with a modified ring. That's the only way to let these lenses keep some of their value intact.
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Forum: Pentax K-1 & K-1 II
05-11-2016, 11:50 AM
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Nope, that is not the problem. The problem is not some part of the black lens housing touching the camera body, the problem is the rear metal ring of the lens touching the camera body. This lens carries the bayonet and the contacts, and on the problematical lenses, it has a much larger diameter than on Pentax original lenses.
When you watch the front of the K-1 closely, you'll see a small indentation above the camera's bayonet ring. This caters for some really fat lenses, but this is outside the bayonet plane (larger distance from sensor plane).
The scratch mark occurs halfway between that indentation and the camera's bayonet ring.
(Nein, das ist nicht das Problem. Es geht nicht darum, daß das Gehäuse des Objektivs den Kamerabody berührt, sondern daß der Bajonettring des Objektivs den Kamerabody berührt. Dieser Metallring, der das Bajonett und die Kontakte trägt, hat bei den Problemobjektiven einen deutlich größeren Durchmesser als bei den Originalen von Pentax.
Betrachtet man die K-1 von vorne, sieht man oberhalb des Bajonettrings eine Vertiefung, die für richtig fette Objektive gedacht ist. Diese Vertiefung aber liegt nicht in der Bajonettebene, sondern etwas davor, d.h weiter von der Sensorebene entfernt.
Den Sigma-Kratzer gibt es zwischen dieser Vertiefung und dem Bajonettring der Kamera).
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Forum: Pentax K-1 & K-1 II
05-11-2016, 11:30 AM
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My 70-200/2.8 II Macro HSM was made in 2009 or 2010. And it's bayonet ring is too wide.
So, no, no recent change in manufacturing by Sigma.
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Forum: Pentax K-1 & K-1 II
05-11-2016, 11:25 AM
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I wouldn't name Sigma a competitor. Sigma fills some niches Pentax leaves unfilled or takes long in filling.
And the availability of a huge range of lenses is something camera buyers look out for, not brand awareness.
If we focus on one kind of "standard" zoom lens, the fast 70-200, then Pentax didn't offer anything in the last decade.
The 80-200/2.8 "power zoom" was discontinued in 2004, and the next lens in that range just came out this year.
So users had to use 3rd-party lenses, and when you compare Tamron's offering, that still uses the outdated screwdrive AF (slow&noisy), the now infamous Sigma 70-200/2.8 II HSM was the logical choice.
The same applies for users of ultra-wideangle lenses. On APS-C, the shortest lens offered by Pentax is the 12-24; Sigma offers a 8-16. That's a vast difference. On full-frame, the shortest rectilinear lens offered by Pentax is the rebranded Tamron 15-30, whilst Sigma used to offer a 12-24. Again, a big difference, if not as huge as between the two APS-C lenses.
Yes, Pentax doesn't exist in a vacuum or in an ivory tower; they should be aware that there are real reasons for their customers to use 3rd-party lenses. Hence a simplistic "it's 3rd-party, we don't care" stance isn't the way to go, that would be blind and dumb arrogance.
And we've seen that Pentax, being not the largest and fastest shark in the pond, takes some time and energy to come up with new lenses. Most of these are not Pentax designs, but OEM products by other lensmakers, Tamron and apparently Tokina. So Pentax (and us Pentax users) would profit from a cooperation with Sigma. Sigma on their side would also profit from that, using licensed specifications instead of having to reengineer everything.
Regarding Tamron: As a licensed OEM lens manufacturer, they should be abled to offer more of their lens portfolio for Pentax users. Of course, direct competitors of lenses that are sold rebranded as Pentax lenses won't do, but Tamron has lots of lenses that are neither OEM'd by Pentax nor competitors to anything else Pentax has to offer - see for instance the 150-600/5-6.3.
And we Pentax users would have the chance of using longer lenses without selling our cars - the 560/5.6 may be a lens of outstanding quality, but it's plainly much to expensive, so the aforementioned Tamron lens clearly fishes in another pond. And just think about Nikon's 200-500/5.6, which costs about two thirds of what Pentax wants for the 70-200/2.8.
Well, let's hope that the K-1 blew enough fresh wind in the camera market so that we users could get more lenses and Pentax more market share.
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Forum: Pentax K-1 & K-1 II
05-11-2016, 10:35 AM
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I've just checked this, since I found it hard to believe. It's not the plastic housing, but the metal ring bearing the bayonet and the contacts. That ring's diameter ist far larger than on a Pentax original lens, and that ring touches the camera body.
On the Pentax 18-55/3.5-5.6 WR lens, that ring has a diameter of a wee bit less than 59 mm.
On the Pentax 24-90/3.5-4.5 it's even smaller with about 58.5 mm.
But on the infamous Sigma 70-200/2.8 II Macro HSM this ring has a diameter of about 65.6 mm.
And this part touches the camera body and --yes, indeed-- leaves a scratch mark.
So there are now two reasons for Sigma to repair that lens.
Other Sigma lenses are slighty smaller, the 70-300/4-5.6 OS DG for instance is about 62.5 mm in diameter, as is the 8-16/4.5-5.6. The 10-20/4-5.6 is even smaller than that.
These measurements are not extremely precise due to the shape of that ring, it's outside is not cylindrical, but with a tapered shape; the smallest diameter is towards the camera, and I've just held a caliper onto it.
But definitively the 70-200/2.8 needs some work with that ring.
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