[THoog]

it is only a change of the little tiny metal element on the back end (I am sure I am missing something, so I fasten my seatbelt to learn something )

Okay, I'll bite.

Sigma's mount change program only applies to lenses that they already produced in K-mount, meaning they produced enough spare K-mount-specific parts for that lens during the production run to be able to switch out those parts in the service center.

Every version of a lens requires a certain number of parts that are custom for that version (of course there's more than just the metal mount plate - the aperture control mechanism is different on each brand, as are the electronics). The lens maker is going to do their best to reuse parts in multiple designs, but there are still the labor costs of designing/testing the custom section for each version of a lens. If they have to make custom tooling for a version, well, precision tooling isn't cheap. In addition, there are fixed costs to stopping the assembly line to retool for a different product, whether it be a different version of a lens or a completely different lens. There are inventory costs of storing and keeping track of each version. It adds up.

Pentax is only about five percent of the DSLR market these days, so (if the proportions hold for lens sales) for every K-mount version of a lens sold, they sell ten Canon and nine Nikon. The lens maker has to decide if the fixed costs are worth it when they are only going to sell five hundred Pentax-version lenses, compared to five thousand Canon-version - or if they would be better off switching to another design that they can sell five thousand of. They could pass the costs on to us in the form of higher prices (and we'd complain), they could cut features like OIS and leave the price the same (and we'd complain), they could get Pentax to subsidize the higher costs and pass them on in higher prices for Pentax-branded versions (and we'd complain), or they could just say "it's not worth it".

[THoog]

I wouldn't go that far, but I think most big spenders (i.e. pros) are shooting Canon and Nikon. There are also some Pentax shooters who exploit the brand's backwards-compatibility, which hurts lens manufacturers.

After running into a young lady with a Pentax at the zoo last weekend, and the best she could say about Pentax was "it was cheap", and thinking of the other Pentaxes I've seen in the wild lately, I think I could go as far as "cheap consumers". I had the most expensive rig of any of them, and I don't recall ever buying a body or lens that cost more than ~$700. (I'd like to think it's the weight of the high-end glass holding me back, more than the price, but it's probably the price.)

[CarlJF]

Sigma has their mount changing program. Ok, I am not a pro and understand all the implications behind this, but to me it seems that it is not that hard work to produce a lens in different mounts. so, since all glas is produced in the same hall... why wouldn't they produce some pentax versions too when it is only a change of the little tiny metal element on the back end (I am sure I am missing something, so I fasten my seatbelt to learn something ) thanks mates!

And this is exactly the point behind the KAF4 mount. You only have the change the metal piece to a K-mount one, flash the firmware, and that's it. In theory, a KAF4 lens doesn't need to be different than a Canon or Sony one, apart the mount itself and the firmware.

However, with KAF3 and older mount it's not possible. You also have to add a mechanical aperture mechanism. Meaning that to produce lens in K-mount, the manufacturer has to dedicate a production line for the lens. It can't take a lens part common to all mount and just screw the right mount on it inn the last step. Or you can't convert a Canon mount to K-mount by simply screwing in the right mount.

[i5_david]

Cool, thanks guys. I was pretty sure I was naive about this... thanks for the insights. the KAF4 mount sounds really good. Maybe we will see some good glass in near future based on this concept? The K-1 is capable of handling KAF4 lenses, isn't it?

So, now all eyes on Ricoh, they have in a few hours their conference, don't they?

[CarlJF]

Cool, thanks guys. I was pretty sure I was naive about this... thanks for the insights. the KAF4 mount sounds really good. Maybe we will see some good glass in near future based on this concept? The K-1 is capable of handling KAF4 lenses, isn't it?

KAF4 is supported by K1, K3ii, K-70 and KS-2. We can at least hope to see more lenses from third-party manufacturers. Although they will have some work to do, it's easier to just convert the mount and firmware than to replace an electronic aperture system by a mechanical one, which may also need a significative redesign of the lens or simply be impossible to do. This also lower production cost since the bulk of the manufacturing cost is shared with other mounts with electronic aperture system, lowering the number of lenses needed to make the production profitable. We'll see...

[Zygonyx]

I'd appreciate that any Sigma's lack of K-mount complainers tells us first wich sigma lenses he bought new in the last decade.
At such a point - that could be fixed around 3 to 5 lenses-, we could understand, but I guess the whinners are rarely the real customers..

[THoog]

KAF4 is supported by K1, K3ii, K-70 and KS-2.

and the K-S1, with a firmware upgrade (same as K-S2). I know most folks would prefer to forget the K-S1 ever existed , but it's in the list of supported bodies on the Pentax page for the 55-300 PLM.

[RonHendriks1966]

I'd appreciate that any Sigma's lack of K-mount complainers tells us first wich sigma lenses he bought new in the last decade.
At such a point - that could be fixed around 3 to 5 lenses-, we could understand, but I guess the whinners are rarely the real customers..

I bought Sigma 70-200mm/f2.8 EX DG OS HSM new in october 2011. I think I payed 1199 euro for it at the time.

I needed that lens for EC boxing women 2011.
https://flic.kr/p/mbCswQ


Oh and I bought new (very old stock) Sigma 170-500m/f4-5.6 DG or so in a Germany shop. It was there for a very long time. Nice lens and sold it after 6 weeks.

[THoog]

I'd appreciate that any Sigma's lack of K-mount complainers tells us first wich sigma lenses he bought new in the last decade.
At such a point - that could be fixed around 3 to 5 lenses-, we could understand, but I guess the whinners are rarely the real customers..

Not sure if I make the cut - I think I have four. An 18-50/2.8 (which shredded its zoom gearing, as that model tended to do), a 10-20/4-5.6 (I think I bought it new), a 30/1.4 EX (on closeout, I admit), and a 30/1.4 ART (I said if they'd do it in K-mount, I'd buy one. They did; I did.). I've been thinking about a Bigma or the occasionally-re-released 8-16, but I just don't know if I would use them enough to justify the expense/inconvenience of lugging them around - these days, I'd rather carry a sackful of small primes.

[gaweidert]

Well I do have a 17-70 Sigma that I like a lot. And my wife got me a 300mm f2.8 lens for my birthday/retirement earlier this year.

I tossed two Sigma lenses a few years ago due to element separation issues and degradation of the infamous Zen coating. Both lenses suffered the same problem. Tossing the 400mm F5.6 APO hurt. That was a good lens when I first got it. Sadly it did not age well.

[thibs]

And this is exactly the point behind the KAF4 mount. You only have the change the metal piece to a K-mount one, flash the firmware, and that's it.

Nope it's not just it.
This is way more complicated.
No mechanical part is easier of course but it does not end there.

[monochrome]

Nope it's not just it.
This is way more complicated.
No mechanical part is easier of course but it does not end there.

Correct. They have to reverse engineer everything, including embedded Signals to work with the Pentax Firmware.

[Kunzite]

I'd appreciate that any Sigma's lack of K-mount complainers tells us first wich sigma lenses he bought new in the last decade.
At such a point - that could be fixed around 3 to 5 lenses-, we could understand, but I guess the whinners are rarely the real customers..

Excellent point. You want Sigma to make more K-mount lenses? There's only one solution: buy Sigma K-mount lenses. That's the only way Sigma would see the increase in sales they're waiting for.

[i5_david]

waiting for my 35 ART this week

[THoog]

Correct. They have to reverse engineer everything, including embedded Signals to work with the Pentax Firmware.

+1. While it appears they all transmit digital data serially over a single pin, the 'E' type F-mount pinout appears to be more like the EOS than KAF; both have a clock signal coming from the camera that KAF lacks. It may require completely different electronic components on the lens side (i.e, if there is a processor in the lens that needs a CLK signal, there has to be something to generate it in the KAF version). Even if they can do it all in firmware, they still have to pay someone to write/test the firmware for each mount-version of a new lens, the cost of which has to be spread over the number of units sold.