Originally posted by kunik Its not an apology, its just a fact. I know I won't notice a difference so why should I care. I have yet to see any numbers as to just how slow it is so I would hold off on final judgment until I see some numbers or try the lens myself. Do you know if or by how much this is slower than Sigma/Canon/Nikon?. Some people demand a minivan that handles like a sports car. I know that Pentax does not handle like a sports car and they do not need to apologize to me for that.
Without some sort of predictive ability the focus speed of a pentax lens will not matter to me. My fastest focusing Pentax lens (in my subjective opinion) is my 300/2.8. I can't really be certain if it focuses faster than my Canon 1DmkIII with its 70-200/2.8 lens, because the Canon has AI Servo. So ultimately the Canon does a much better job of focusing on fast moving objects but is that because of AI or focus speed?
I can definitely tell the SDM motors turn a little slow on long throws (on my DA* lenses) but its more quirky than annoying for me. Now when Pentax comes out with a sports oriented body it might start to matter more but until then it works fine for me.
edit - I don't intend to be argumentative but when people start complaining about Pentax on a public forum about things that matter to them but do not matter to me I think its valuable to include a note representing an alternative point of view. Pentax does not sponsor me and they never replied to my request for participation in their professional program but I sincerely enjoy their gear and I honestly don't consider the so-called negative points about Pentax to be a concern for me. I've been shooting a $4000 Canon for 4 months now and I can honestly say I still prefer my K20D (and I've take more than 20,000 pics in that time - between the two brands). The different bodies and lenses require different techniques to achieve good results but although saying "Pentax has slow focus" may be factually correct in relation to the Canon it does not prevent me from getting the images I want so does it really matter?
Let's turn it the other way: would faster AF be a problem on such a lens? Would it prevent you to take the kind of shots you like?
If not, then why make it slow since it would suit everyone better?
Why the 4000$ Canon gear if you prefer your Pentax?
Pentax introduced a new AF mechanism in SDM, I thought it might not be faster than conventional screw-driven motor on some lenses but I certainly didn't think it would be slower.
The FA 50f1.4 is about as fast as the Canon 50f1.4 USM which has the same kind of micro motor than our SDM lenses, I expected the DA 55 to be about the same speed, not much slower: was that expectation unreasonable?
I know, I know:
It's a portrait lens, so it is optimized for MF !
Real photographers only use MF anyway!
Fast AF is useless without good AF tracking ! (good one!
)
(Insert the corny usual justifications for slow AF here)
... ... ... ...
Canon has fast USM AF, Nikon has fast AF-S AF, Sony has fast SSM AF and even Olympus introduced fast SWD AF but Pentax has missed the opportunity to erase the only real recurring complaint USERS have with their brand by introducing the slowish SDM AF.
Of course, it's a good thing since it differentiate us, discerning Pentax users, from the Canikon crowd: see, slowish AF is a FEATURE, not a compromise imposed by wrong techno-economical choices...
But I suppose it's OK because Pentax is in a niche player or because Pentax users know better than using a portrait lens for anything else than static portraits or because some of us don't use AF at all...
Anyone else getting tired of hearing this kind of justification?