The "power-zoom-power-contacts" power (they deliver the required energy) for the SDM. Regulation of the AF is another story. Close-up rings without optical elements focus without problems. There is just a need of data communication. Probably, there will be a massive need of firmware-updates in the near future, as Pentax DSLRs currently do not know of the existence of any teleconverters. Pins which transfer data, however, already are available.

At least my subjects are not always in the middle of the picture .

Also at the (extreme) borders?
http://www.photozone.de/images/8Reviews/lenses/pentax_43_19_k5/mtf.png
It might be less critical on m43.

EDIT:
Compare 43/[email protected] and 50/1.4@f2 on K10D:

http://www.photozone.de/images/8Reviews/lenses/pentax_43_19/mtf.gif

http://www.photozone.de/images/8Reviews/lenses/pentax_50_14/mtf.gif

Weekend bump!

All serious offers considered.


EDIT:
Another copy of this lens is currently listed at B&H for 499$:
http://www.bhphotovideo.com/c/product/142491-REG/Tamron_A76100_28_105mm_f_2_8_LD...

Yes.

In principle, this lens is quality wise like an A* 300 but with autofocus ... and with Tamron instead of Pentax lettering .

Well, I have (or had) M 40/2.8, (Revuenon 55/1.2), (K 50/1.2), M 50/1.7, M 50/4 Macro, A 50/1.2, (A 50/1.7), (V 58/1.4), (F 50/1.7), (FA 50/1.4), (FA 50/1.7), FA 50/2.8 Macro, (FA 43/1.9), DA 40/2.8 LS, (DA 55/1.4). There are just too many 50ies out there .

What I disliked most about the FA 43 is the sawtooth rendering of the aperture blades in backlighting conditions. Also, the sharpness is not really convincing at open aperture, which is only f1.9: http://www.photozone.de/pentax/736-pentax43f19k5?start=1 The 31 is the only FA limited that I kept - although the others also are silver .

My favourites are the K/A 50/1.2 and the 50/2.8 Macro. The latter was often stated to be one of the sharpest lenses by Pentax. IIRC camera adjustment was performed with this lens at Pentax Hamburg.

Sold - payment pending.

I have noticed that, thanks!
Pitiful chicken .

Coming back to the metering:
I dislike the green button, thus the above linked petition.

But:
If you compare lenses at the same ISO with the same f-stop under the same lighting conditions, you could/should meter once correctly and then keep the shutter speed for all lenses. By this you also could decide whether the indicated f-stop really is correct and not only labelled as such.

I would be interested, the problem again just is UK Only .

Have you tried something like this:
http://www.dslr-forum.de/showpost.php?p=10501282&postcount=61
Your item really could be helpful if you could use filters with the 8-16.