SDM Lenses

Although another thread is running for "issues" with these lenses, don't forget that these are first generation motor driven lenses as far as Pentax are concerned. Just as other makers have slow and fast AF lenses, Pentax will need to address any issues raised.

An example of a slow lens for Nikon is the 80-400mm, it is not up to sports coverage. Other lenses in their range are just silly fast.

The whole system has to be matched for speed, the AF within the camera and the motor/servo system within the lens.

I think that we will have to give Pentax time to develop a faster system.

Regards

Gary, you don't need to defend Pentax.
It's one of the only brands I believe that didn't want to put behind users with an older camera that can't use SDM so also put a screwdrive with them (KAF2 mount).
Canon I believe switch systems completely in one go, leaving behind users with older camera's.
Only recently pentax have brought out SDM only lenses (KAF3) so lets wait what Pentax can do when they put more effort in that.

The DA*55 is a KAF3 mount and I must say I had higher hopes for the AF with that one, maybe the K7 speed it up a bit, does anybody knows that?

Hi Stefan,

I probably put my points across wrong as I didn't intend to make it a defence statement, more to highlight that for Pentax it's a first step. With respect to the lens compatibility, no issue, it's a huge advantage to those with older glass.

Regards

There are often topics on the forum that I have not got a clue about, I am completely in the dark in respect of 'SDM', for me and anyone else who doesn't know an explanation would be much appreciated

Regards

Chris
K200D,18-55,50-200,FA50.M50

Chris, SDM means Super Direct-drive Motor (ultrasonic autofocus)

Its supposed to be fast and silent when focusing at least on the digital bodies.

There is a good read here

They are exceptionally good with great IQ, weather sealing and very light at least that is my experience.

May I pick you up on two things Amin,
USM they are not, (Ultra sonic motors) Canons "ring motors" very fast, the same as Sigma’s HSM, "Hyper sonic motors"
SDM, as I understand it is for "Silent drive motor" a micro motor similar to the Tamron version, the only very fast drives at the moment are of the ring type.
And yes you also require very fast AF to go with it, i.e. the newest Canon version on their 7D, so Pentax does have to make lots of improvements yet.

I stand corrected then Richard, thank you for your clarification.
I see then that's the reason why the Sigma version is faster compared to the DA*60-250.

Thanks again Richard

Thanks very much for the explanation.
So much to learn

Regards

Chris

If Pentax say it's Supersonic Direct-drive Motor then it's Supersonic Direct-drive Motor link

Ultrasonic motor is a type of motor that vibrates and that vibrations is turn into motion. link

Canon use three kind of USM motors, and the micro type is the same as Pentax use as stated above correctly.

Stefan

I think Richard meant to correct my (ultrasonic) term added in the line where I explained what SDM stood for. I just copied that from another forum and obviously seems wrong.
What I should have put there after the SDM explanation was (significantly faster and operate more quietly than conventionally driven AF lenses.

Ahhh the joys of learning .

It's always of help to clarify what means what. It still leaves us with a fledegling system that has a way to go before the only posts about SDM AF will be Yipeeeee!!!!

Regards

Yes I know Amin but what you stated was right though, only the fast part they are lacking with though
Here see this link

One thing you must agree on Stefan, is "Supersonic" focusing they are not, wishfull thinking on Pentax's part! IMHO.
I could call my car a Formula 1, but that would be a joke

Arther, I agree on that.
They need to improve that quite a lot.
Although I don't know if the lens is fully to blame since every SDM lens is focusing faster with every new generation camera coming strangely enough...
Maybe Pentax are deliberately keeping them slow???

Hang on chaps, Time Out, me thinks. We praise the ability to use older MF glass and then raise issues over a newer generation glass that works reliably and is in it's infancy.

Are we daft or what? I bet more Canikon readers read our threads than watch Pentanation Street, Pentadale Farm or East Pentenders.....just to see what the in-house gossip is all about or for a laugh..

Regards