da* 16-50 f2.8 artificially restricted to f2.8?

Yeah, man... Go ahead and mess around with the "innards" of that $1,500 MSRP lens you likely paid AT LEAST more than $900 for (last time I looked, it's FINALLY back down around $920, or so, which is roughly what I paid for it when I bought my K-5 in July 2011).

Frankly, I agree with the other posters that there are likely very good reasons it's "artificially restricted" from going below F2.8 at 16mm, and I certainly wouldn't wanna mess with the lens to find out why -- especially not with these lenses already having known issues with their SDM focusing motors! I've been VERY happy with mine. I'd suggest you leave well enough alone.

Jeff

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A word is worth 1/1000th of a picture... Maybe that's why I use so many words!