[UncleVanya]

The reason why I suggested that is because there aren't issues btwn this lens and the k-3. Something changed on the Pentax end that (who knows) may be a simple fix.

That's true but what if the thing that changed is the same thing making it faster focusing even on legacy Pentax lenses by some reports? Perhaps the change is with the Pentax spec but not within the reverse engineered spec that Sigma uses.

[Flasher]

This is both Pentax and Sigmas problem. Sigma for not coding their lens (using the generic 8 255 instead) and Pentax for not accepting and handling that code properly. Pentax needs to fix this first after all if the lens worked on the K3 it should work on the K1. The problem might lay in the crop selection process but the camera should not freeze. That is a bug.

There are few Pentax users as it is so having this as a deterrent to upgrading is not good for business.

As always though there will be a few firmware upgrades to fix bugs etc. as this is a new product and of course the inevitable K-1 Mk2.

[disasterfilm]

Hi guys - following back up on a promise I made back on page 2 of this thread.

The 70-200 HSM II works on the K-1 with the K-7 firmware update.

Pre-update, my lens's ID was an 8.255. Post-update, it's an 8.16. I took it out with a K-1 and everything works flawlessly.

If you're having this problem, don't panic, but go to Sigma's webpage and put in a service request order to update the firmware. They updated the firmware in my lens in (I think) 8 calendar days door-to-door.

I already emailed the Sigma service rep who helped me out when I sent my lens in in January, and let him know that the K-7 firmware update on an 8.255 lens is now functional, so hopefully folks at the service center are somewhat aware that there's a fix.

No problems at all, btw, in my 8.255-version 24-70 HSM. Well... I think it's an 8.255, but now I'm second guessing.

[dcpropilot]

Hi guys - following back up on a promise I made back on page 2 of this thread.

The 70-200 HSM II works on the K-1 with the K-7 firmware update.

Pre-update, my lens's ID was an 8.255. Post-update, it's an 8.16. I took it out with a K-1 and everything works flawlessly.

If you're having this problem, don't panic, but go to Sigma's webpage and put in a service request order to update the firmware. They updated the firmware in my lens in (I think) 8 calendar days door-to-door.

I already emailed the Sigma service rep who helped me out when I sent my lens in in January, and let him know that the K-7 firmware update on an 8.255 lens is now functional, so hopefully folks at the service center are somewhat aware that there's a fix.

No problems at all, btw, in my 8.255-version 24-70 HSM. Well... I think it's an 8.255, but now I'm second guessing.

That is truly awesome. Thank you so much.

[stevebrot]

and Pentax for not accepting and handling that code properly. Pentax needs to fix this first after all if the lens worked on the K3 it should work on the K1. The problem might lay in the crop selection process but the camera should not freeze. That is a bug.

Yes, the fix is to detect the fatal condition before it happens, disable most functions, and signal the user that an incompatible lens is present.

BTW...The problem is probably not the "8 255" code in and of itself. It is unlikely that codes for other than Pentax lenses are recognized as significant by the camera. More likely is that there is a bug in the reverse-engineered protocol being used where an expected value is out of the expected range.


Steve

[tim60]

With a lens that works perfectly fine with at least the K10D and the K-5 (and most presumably also the K-3)?

Sorry, I don't accept that. And even if the lens would be sending faulty data to the camera, the camera should not freeze. This is poor and faulty software design; Pentax is definitively quite aware that there are "3rd party" lenses around and that there are perfectly acceptable reasons for Pentax users to use these lenses, other than Pentax' somewhat high-classy pricing.

In the fast 70-200mm range, Pentax just now came with a new lens; prior to that, they had nothing comparable. And ... let's be realistic, Pentax' pricing is somewhat off the ground here, the 70-200/2.8 costs more than double than what the Sigma lens did cost. Pentax' offering is even more expensive than Nikon's new 200-500/5.6!

In the super-wide-angle range, Pentax has nothing to offer. I'm using Sigma's 8-16/3.5-5.6 on a K-5 with excellent results, and had Sigma not withdrawn their 12-24, I'd have planned to obtain one for use with the K-1. No, Pentax' 12-24 is an APS-C-only lens, not comparable.

So, as I've said, there are viable reasons for Pentax users to use "3rd party" lenses.


And the stated claim is "compatibility with every K-mount lens ever made" not "compatibility with pentax-made K-mount lenses only".

The Canon incompability you've mentioned stems from something different. Canon steers both AF and aperture electronically on every lens. With the switch from film cameras to digital cameras (both branded "EOS"), they've slightly changed their interpretation of the protocol used to steer the aperture, thus rendering older 3rd-party lenses incompatible.

Were there a similar problem with older "3rd-party" lenses for Pentax, neither the 24-70 nor the 70-300 I've mentioned should work.
The latter even offers OIS, working, on the K-1! OK, none of them is a SDM lens. But the 8-16 is a SDM lens, and that one works on the K-1.

It is plausible.

I saw a PF user last year who had a K5 and a 3rd party lens that would not auto focus on K5. We put the same lens on my K3 and it did auto focus. I think it may have been Sigma.

My point - there could be something subtle happening that prevents correct operation that does not show on all camera bodies.

[Flasher]

Yes, the fix is to detect the fatal condition before it happens, disable most functions, and signal the user that an incompatible lens is present.

BTW...The problem is probably not the "8 255" code in and of itself. It is unlikely that codes for other than Pentax lenses are recognized as significant by the camera. More likely is that there is a bug in the reverse-engineered protocol being used where an expected value is out of the expected range.


Steve

That just proves that it is a Pentax problem since a generic 8 255 code should indicate that it is a Sigma lens of unknown value. For some reason the K3 accepts this but not the K1.

You are probably right about the code, likely it is the K1 sending a new pentax command that the lens does not recognise.
The K1 freezing indicates a possible bug in the firmware but it could be the lens going crazy and swamping the comms to the camera or it could be any number of other things. Of course the best fix is Sigma upgrading the lens then the camera can adjust to suit the lens (if Pentax actually does this on OEM lenses) and also post processing software can apply lens corrections but in the mean time making the K1 bullet proof would keep everyone happy. I suspect the first firmware update fixes this problem.

I have an old 28-70 f2.8 Sigma EX full frame lens (screw drive) that I love but it returns 3 255 so I have to apply a preset of my own. I hope it works ok on the K1 as it is my favourite most used lens. I will be waiting for the K1 Mk2 though after buying the K5 Mk1 and K3 Mk1.

[UncleVanya]

I will be waiting for the K1 Mk2 though after buying the K5 Mk1 and K3 Mk1.

Was you k5 or k3 experience bad? Or are you pointing out that you we're willing to take the risk on those but not this one?

[Flasher]

Was you k5 or k3 experience bad? Or are you pointing out that you we're willing to take the risk on those but not this one?

The K5 had the ttl flash issue, the Mk2 didn't fix that but the K5IIS would have been nice without the anti alias filter.

The K3 has the mirror flap problem but I must admit I would rather have the built in flash than the GPS, much more useful for me. The pixel shift would be nice to have though.

Since the K-1 is considerably more expensive here in Australia I wont be jumping into the first issue until any major problems have been identified. Probably 6 months should be enough time for anything to show up with the added bounus of the price possibly dropping.

Having said that the K3 has been a fantastic camera and I've only had the mirror problem a few times, other than that it performed flawlessly. I didn't get to use the K5 much before the K3 came out.

I have now learnt that Pentax seem to bring out a Mk2 version within a year so experience has told me to wait particularly considering I am very happy with the K3. The IQ of the K-1 will be it's biggest feature for me.

[Kunzite]

I have now learnt that Pentax seem to bring out a Mk2 version within a year so

Of the K-1? No way.

[stevebrot]

You are probably right about the code, likely it is the K1 sending a new pentax command that the lens does not recognise.

It is hard to say, except that this sort of thing (lack of backward compatibility on 3rd-party lens/flash) is quite common and not just with Pentax. I would have expected that the lens would simply not AF properly. Camera crash is another thing entirely. Pentax needs to fix the crash problem. As for Sigma, indications are that they have updated firmware that can be flashed onto the effected lenses.


Steve

[Raffwal]

My K-1 arrived this morning. It is with much relief that I can report that the following Sigma lenses works perfectly:

• 24-70mm F2.8 IF EX DG HSM - "8 255" (Generic Sigma)

Can you comment on the IQ and AF accuracy using this lens?

[jbrowning]

This is the Sigma 70-200 that I use 90% of the time. Is it one that is working with the K1? Sorry I'm so confused with all the different variations of this lens.

Sigma 70-200mm F2.8 EX DG APO Macro HSM II Lens Reviews - Sigma Lenses - Pentax Lens Review Database

Thank you
Jim

[rawr]

Is it one that is working with the K1?

There seem to be reports of it working on the K-1, and reports of it not working. It seems like a case of try it and see.

I am also a 70-200 HSM II owner, so when I get a K-1 it will be the first lens I test.

[jatrax]

There has also been at least one post saying that a firmware update already available fixes the problem.

So the variable reports might depend on how old the lens is and what firmware version is installed.