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View Poll Results: What do you think about SDM?
Nothing for me. I don't need it, I don't want it and I'm not willing to pay for it. 1414.74%
Sometimes good to have it, although I pesonally can live without it. 1818.95%
Nice feature! If SDM lenses are affordable, I will surely buy some. 3536.84%
I'm looking forward to more SDM lenses and I will prefer them. 2829.47%
Voters: 95. You may not vote on this poll

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01-27-2008, 04:29 AM   #1
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About SDM

Hello everybody

I'd like to start a little discussion about the supersonic motors, SDM, and possibly learn more about this feature from the ones that already had the possibility to use SDM lenses. I'm a newbie here, so I hope this topic hasn't been discussed elsewhere, but I didn't find it

I had no chance to try any SDM lens yet unfortunately (I had just my hands on a Nikon with a Sigma HSM lens for a while), so… my question for now is whether there is some difference regarding the using of a SDM lens when comparing to other vendor's supersonic focusing implementation (like USM, HSM etc.).

I was a little bit confused when reading the specification of new SDM lenses and there was also Quick-Shift Focus System mentioned, because although Quick-Shift is nice feature, I think that it is superseded by supersonic motors. Am I wrong? Isn't SDM full-time manual and is it rather like a micro-USM or is Quick-Shift active only with screw-drive bodies, while SDM is truly full-time manual (and therefore Quick-Shift is effectively not used with SDM-capable bodies)?

Thanks for your comments and for clearing my doubts.

01-27-2008, 05:21 AM   #2
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QuoteOriginally posted by Gumysh Quote
I was a little bit confused when reading the specification of new SDM lenses and there was also Quick-Shift Focus System mentioned, because although Quick-Shift is nice feature, I think that it is superseded by supersonic motors. Am I wrong? Isn't SDM full-time manual and is it rather like a micro-USM or is Quick-Shift active only with screw-drive bodies, while SDM is truly full-time manual (and therefore Quick-Shift is effectively not used with SDM-capable bodies)?

Thanks for your comments and for clearing my doubts.
Yes, you are correct, SDM is designed to be full time manual. The focus clutch system is still in place for those with non-SDM capable bodies that is driving the lens via the screw. The screw drive isn't used at all when fitting a SDM lens on a SDM body.
01-27-2008, 06:36 AM   #3
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Thanks for the reply, Avant My feeling from the short experience with the friend's HSM Sigma is very good; recently I experienced several situations when AF with instant full-time manual override would have been handy. So now I hope that there will be more supersonic lenses - I wish Sigma stopped ignoring Pentax and began to make HSM-enabled lenses for K-mount as well. Although I don't really expect it soon Or has anybody some positive news?
01-31-2008, 04:58 AM   #4
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I dug some more information at Forums: Digital Photography Review. According to the posts there it seems that (at least current) SDM implementation is not as smart as I though, since it is not of the ring-type Then it's twice as good news for me that Sigma introduces HSM for K-mount while HSM should be ring-type motor. Well, we'll see - I think that Sigma could have some advantage here.

01-31-2008, 05:28 AM   #5
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I voted sometimes good to have but I can live without it because I have already for over 25 years.

Hell I lived without AF for half of that.

Is it a good advance, yes

Will I get some, yes probably in the future

Will I trade all my lenses now just to have it. NO
01-31-2008, 06:11 AM   #6
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According to the Pentax DA Interchangeable Lens Operating Manual, pages 12-17, the SDM lenses are always used with the camera body focus mode switch set to one of the autofocus positions. The lens AF/MF switch can then be set to either auto focus or manual focus. If it is set to auto focus, then the Quick-Shift Focus System will allow manual focus touch-ups using the lens focussing ring, so long as the shutter button is half-pressed or the AF lock switch has been pressed.

The Quick-Shift System is explicitly intended for use when the camera/lens combo is in auto focus mode, and the System is very much able to be used with SDM-capable bodies, not just the screw-drive auto focus bodies.

With respect to Sigma, here's the text of a little e-mail exchange I've had recently with their US office:

A definite direct answer I do not have all I can say is that Japan may feel
that the market for HSM wouldn't be beneficial to start production on as it
would for Canon or Nikon.
It would be a costly process and even though the Pentax market is growing it
still isn't as popular in demand as the Canon and Nikon markets.

There may be sometime in the future where they may produce HSM for Pentax
but as for now there isn't.

Best regards,
*
Customer service/technical assistance
Sigma Corp of America
15 Fleetwood Court
Ronkonkoma, NY 11779
631-585-1144
631-585-1895 Fax
dgaige@sigmaphoto.com



-----Original Message-----
From: Christine Landon
Sent: Thursday, January 10, 2008 6:48 AM
To: info@sigmaphoto.com
Subject: Re: HSM for Pentax K10D?

Dear DG,

Thank you for responding, but you left a couple matters rather vague,
so I wanted to follow up.

You wrote:

newer Pentax digital have something in the body that is similar to
what our
HSM does
It is my understanding that HSM is an autofocus motor built into the
lens that uses ultrasonic waves to drive the lens' focus instead of
using a camera body focus motor driving the lens through a mechanical
coupling. Sigma's HSM lenses would be comparable to an SDM Pentax
lens, if I'm not mistaken. The "something in the body" that the K10D
has is a standard body focus drive for non-SDM (HSM?) lenses, those
lacking an in-lens, ultrasonic drive focus motor. I persuaded that in-
body focus motors in any DSLR cannot produce focus with the same
speed and quietness that an HSM/SDM/AF-S /USM/SWM lens can achieve.
So, why wouldn't Sigma want to make the benefits of its HSM lenses
available in a Pentax mount for the K10D, which can take advantage of
ultrasonic lens focusing motors?

I originally asked about Sigma lenses in the EX HSM series, but did
not mean to include the OS lenses; sorry if I wasn't clear, but I
know that in-body shake reduction precludes the need for in-lens OS.
Still, there are some nice, non-OS lenses in Sigma's EX and EX HSM
lines that I'd seriously consider buying if they were available in a
Pentax KAF2 mount. I'm sure that there are thousands of current
Pentax digital owners who'd agree. Is there any reason Sigma would
neglect such a group of potential customers?

All my relations, Christine

On Dec 26, 2007, at 12:20 PM, DG wrote:

As of now we will not be producing HSM for the Pentax mount because
the
newer Pentax digital have something in the body that is similar to
what our
HSM does and it also has an image stabilization in the body.

We may be introducing new lenses at PMA in Las Vegas this year so I
would
check back after the end of January to see if there are any new
announcements on our website.

Best regards,

Customer service/technical assistance
Sigma Corp of America
15 Fleetwood Court
Ronkonkoma, NY 11779
631-585-1144
631-585-1895 Fax
dgaige@sigmaphoto.com


-----Original Message-----
From: Christine Landon
Sent: Monday, December 24, 2007 2:20 AM
To: info@sigmaphoto.com
Subject: HSM for Pentax K10D?

Dear Folk at Sigma,

Just another new Pentax K10D owner wondering whether to to save up
for any of your attractive HSM tele/zoom lenses. Might a Pentax KAF2
mount version of the 100-300 f4 or 120-300 f2.8, in particular, be on
the market in 2008? I'd seriously purchase either, and would even
bite the bullet for a KAF2-mount 500mm f4.5 EX tele.

All my relations, Christine Landon
02-01-2008, 01:36 AM   #7
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The latest sigma lenses with HSM (the new 70-200 and 50-150, for example) are listed as having the HSM motors in them, and will work on pentax cameras that support the in-lens motor (presumably the K10, K100 super, K20, and whatever else has the two extra contacts), from what I hear. They won't focus at all on other bodies, so it seems to me that they've removed the screw-driven system completely. As far as costs go, it seems that it would be more expensive to have two different production lines (HSM and non-HSM) than to update the pentax designs to HSM.
02-01-2008, 07:04 PM   #8
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SDM did not impress me a bit, I actually sent 50-135mm back to B&H. I guess I was expecting performance close to Canon's USM or Sigma's HSM, but not even close, just quiet and still slow...

So to answer the poll from my perspective:

If SDM is true ultra/hyper or what ever it is in the future (and not that tiny little micro motor) that is quiet, accurate and fast - yes, these are my expectation from any lens costing close to $1000. Otherwise, current version of SDM does nothing for me, I can use my manual glass for the fraction of the cost. Just my $0.2...

Regards,
D

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