[D1N0]

BTW...are you sure about widening for the WR? If so, I would expect a different flange diameter for the *st-series bodies vs. the 2006-2007 era K-series dSLRs (designed to work with the original DA* zooms, Pentax's first sealed lenses).

Yep they did K10D vs *ist DL

[stevebrot]

The published Pentax K mount specs from day one have specified a maximum diameter of 65mm. This goes back to the fully open original K mount, reproduced 1:1 here in this Soviet spec sheet.

FWIW, The zenitcamera.com is fan content gleaned from various sources and not particularly reliable* even for Zenit product (no relation to KMZ, former makers of Zenit SLR cameras). What the linked diagram appears to show is the design specs for lenses intended for the K-mount Zenit bodies.

Below is a Zenit Automat from 1984 mounted to the Zenitar 16/2.8 Fisheye. I measure my copy of that lens as 60mm diameter. It is apparent from the photo that the Russian designers obeyed the 65mm mandate

This maximum has never changed, I repeat never changed on all of the published k mount specs, even the later closed ones.

I won't ask you for links, but will mention that I just measured the body clearance on my Super Program at 2mm from the top edge of the mount flange to the pentaprism overhang. The flange itself measures 59mm diameter. It would appear that 65mm max diameter would be a little generous for the lens flange to mate to that camera.

BTW...did I miss something? I don't see where any of the lenses in question exceed 65mm diameter at the flange or where the max diameter on the K-1 has been measured at 65mm.

Edit: While I was writing this, funktionfrei measure his Sigma 70-200/2.8 II EX DG Macro HSM at 65.5mm. (LINK)


Steve

* The linked diagram uses Latin characters for "min" and "max" in Russian they would be "мин" and "мак". Just a small matter, but probably not a notation by KMZ.

[RonHendriks1966]

Pentax should design their camera around their competitors' lenses?
You're joking, right?

Ofcourse not. But Sigma has also the freedom to stop making lenses for K-mount. See who would be happy then. There is a little room on the K-1 and that is a design thing. Maybe not the smartest choice, but one that isn't going to change. The K-30 had a different kind of design that didn't appeal to many.

[funktionsfrei]

Pentax should design their camera around their competitors' lenses?

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.

[stevebrot]

Pentax never promised anyone K-1 would mount all previous third-party lenses.

Several of the affected lenses are current production with life spans overlapping the K-1 design cycle. What is possible is that Pentax did due diligence with those lenses, but Sigma made a recent change in their manufacturing. For the non-current product, Pentax should have known that the installed user base was significant.


Steve

[funktionsfrei]

What is possible is that Pentax did due diligence with those lenses, but Sigma made a recent change in their manufacturing.

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.

[FantasticMrFox]

Ofcourse not. But Sigma has also the freedom to stop making lenses for K-mount. See who would be happy then. There is a little room on the K-1 and that is a design thing.

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.

These.

[stevebrot]

Yep they did K10D vs *ist DL

Cool!!!


That mount looks about the same as the one on my Super Program. I wonder what the prism housing clearance is on that camera?


Steve

[geko5766]

Hello,

I tried to figure out what may be the issue of Sigma. Neither my 35,50 nor 85mm /1,4 showed a problem.

However it may be thinkable, that a lens may be pushed out at the upper of the mount very slightly, which I could not really see. It sghould be really measures out.
However I made a rough picture of this problem, but I am not the real PS crack.

However here it is:

Best
Georg

[D1N0]

These.

Nope it is better for Sigma to backtrack, so their lenses are up to spec for their customers. Pentax doesn't owe Sigma anything.

[funktionsfrei]

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).

[FantasticMrFox]

Nope it is better for Sigma to backtrack, so their lenses are up to spec for their customers. Pentax doesn't owe Sigma anything.

Sigma are the ones having more pull in this situation. Sigma doesn't make a lot of money with Pentax, hence they are not releasing most of their lenses for K-mount. But the Sigma 'Art' series is universally recognised as probably the best FF prime lens line in existence, and certainly the best bang for the buck. People buy them like sliced bread, and them being not available for Pentax is a drawback.

I am pretty sure Pentax needs Sigma more than Sigma needs Pentax.

[Winder]

It wasn't about the images. Sigma is telling customers their lenses can scratch the body. Can you see where that might be when putting the lens on and maybe make a little video? Basicly Sigma says, don't use them, since we will not cover damage to your K-1 that might occur.

Yes. I can read. Both of my Sigma lenses fit just fine. No issues with scratches on the mount.

[FantasticMrFox]

Yes. I can read. Both of my Sigma lenses fit just fine. No issues with scratches on the mount.

It's not about the mount, it's about the plastic above it.

Edit: Sorry, 'metal above it'

[Caat]

Rather the supplier you link doesn't stock many Pentax K mount lens !
or your search is very poor - which given your results I think is closer to the truth

You list show 29 from all manufacturers of which many are 645 so not K anyway

try this for a better list
PENTAX K Mount Lenses | SRS Microsystems

42 genuine OeM K mount lens
Sigma Pentax Fit Lenses | SRS Microsystems
20 Sigma K mount lens
Tamron Pentax Fit Lenses | SRS Microsystems
7

To be fair a proper filter on Adorama
http://www.adorama.com/l/Lenses/SLR-Lenses?sel=Lens-Mount_Pentax-K

Shows they stock 122 K mount lens (just a little more than your 29 )
Canon and Nikon have about 450 so many more but how many lens counts as enough ??
Sigma only have 66, Sony 200 and 4/3 22

Again this is what Adorama stock not what is in the retail market.

I think quite rightly Pentax/Ricoh couldn't care less is the largest reverse engineering company has burnt their fingers (again)

Sorry, that link was an advertising link inserted by Pentax Forums. I didn't put in there, and I wasn't trying to make a point about lens availability with it.