New 60-250 able to use K-7 contrast AF?

Photomy · 05-08-2009, 01:49 PM

Mr. Mabo mentioned in an earlier post I saw about the need to make changes to any lenses that will use the new real time contrast detect AF sytem and only SDM line will be adaptable. Anyone care to speculate if the 60-250 which was just released was already designed to use the new contrast detect AF system? Maybe this was already answered - I could not find it.

- Tom

**RuiC** · 05-08-2009, 02:22 PM

Originally posted by Photomy

Mr. Mabo mentioned in an earlier post I saw about the need to make changes to any lenses that will use the new real time contrast detect AF sytem and only SDM line will be adaptable. Anyone care to speculate if the 60-250 which was just released was already designed to use the new contrast detect AF system? Maybe this was already answered - I could not find it.

- Tom

The marketing of this lens took longer than we expected just to insure that it would be compatible, I think.

Photomy · 05-08-2009, 04:14 PM

I hope so. With the 60-250 I can get by with just 3 lenses for 90% of my shots. I like the concept of the K-7 from what I hear about is so far from unofficial information. Not sure how much I would use video, but you never know what opportunities it may bring. I hope Pentax comes in with a winner so I can afford to keep my RZii kit and still do some film.

RMabo · 05-09-2009, 01:21 AM

For optimum performance of the contrast detect AF, lenses needs prepared prepared focus motors (do note that Olympus has issued upgrades for their existing lenses to give better functionality with contrast detect AF) or they will focus slower than what is actually possible with the system. The 60-250 has been delayed so long and when it comes now I would be surprised if it wasn't designed with "the new K" in mind since 60-250 would propably be a popular choice among the target users for "the new K".

lol101 · 05-09-2009, 04:08 AM

Originally posted by RMabo

For optimum performance of the contrast detect AF, lenses needs prepared prepared focus motors (do note that Olympus has issued upgrades for their existing lenses to give better functionality with contrast detect AF) or they will focus slower than what is actually possible with the system. The 60-250 has been delayed so long and when it comes now I would be surprised if it wasn't designed with "the new K" in mind since 60-250 would propably be a popular choice among the target users for "the new K".

Do you think older SDM lenses can be upgraded so than people that have just bought DA* lenses can benefit from these advances?

zntgrg · 05-09-2009, 04:42 AM

I think Olympus lenses needed update because they actually have a firmware [i.e. some software on it]: i don't see why a normal electric motor shouldn't be precise and fast enough.

deejjjaaaa · 05-09-2009, 06:30 PM

Originally posted by lol101

Do you think older SDM lenses can be upgraded so than people that have just bought DA* lenses can benefit from these advances?

so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF.

lol101 · 05-10-2009, 01:53 AM

Originally posted by deejjjaaaa

so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF.

That would also include the 60-250 in that case.

AFAIK, this lens features the same AF mechanism that previous ones.

Plus, if SDM is inherently too slow for fast CDAF, what can possibly do Pentax to claim that they needed to upgrade lenses? They certainly did not upgrade them to ring USM did they?

nosnoop · 05-10-2009, 02:24 AM

Originally posted by deejjjaaaa

so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF.

Another pure speculation? There is no reason why micromotors cannot be made to be as fast as ring type.

vinzer · 05-10-2009, 05:45 AM

Originally posted by deejjjaaaa

so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF.

I still think the chokepoint is still in the AF algorithms in place than the hardware itself. Non-ring type Canon lenses are still able performers in AF speed. Not world-beating speed, but still capable.

deejjjaaaa · 05-10-2009, 07:54 AM

Originally posted by nosnoop

Another pure speculation? There is no reason why micromotors cannot be made to be as fast as ring type.

the only speculation here is underlined above

deejjjaaaa · 05-10-2009, 08:02 AM

Originally posted by vinzer

I still think the chokepoint is still in the AF algorithms in place than the hardware itself. Non-ring type Canon lenses are still able performers in AF speed. Not world-beating speed, but still capable.

yes, performers - with PDAF - where you can predict where to move and calculate how much you will need to move the focusing group of optical elements with one measurement... one measurement - one movement (some systems are doing double check though)... now enters CDAF where this is not possible (you need several iterations) and put on top of that AF-C... as for performers, sure - we even have screw driven lenses that can focus fast... with PDAF

Asahiflex · 05-11-2009, 10:27 AM

FWIW: the lens was tested on a Pentax MZ-5n and it appears to be fullframe. See here for the results: Pentax 60-250 SDM Samples: Pentax SLR Talk Forum: Digital Photography Review

Xian · 06-09-2009, 08:04 AM

Won´t screw driven on body motor support contrast AF??
Why...??

and · 06-09-2009, 08:27 AM

it will.
I consider it just a myth that the 60-250 was delayed for some special reason, codiac2600 also mentioned this that "they had plans for it" but I see no special reason why the 60-250 should be delayed it doesnt have any special feature that the other DA* has

05-08-2009, 01:49 PM	#1
Photomy Senior Member Join Date: Jan 2007 Location: Kansas City, MO Posts: 174	New 60-250 able to use K-7 contrast AF? Mr. Mabo mentioned in an earlier post I saw about the need to make changes to any lenses that will use the new real time contrast detect AF sytem and only SDM line will be adaptable. Anyone care to speculate if the 60-250 which was just released was already designed to use the new contrast detect AF system? Maybe this was already answered - I could not find it. - Tom

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05-08-2009, 02:22 PM	#2
RuiC Site Supporter Join Date: Jan 2009 Location: Lisboa - The best destination in Europe Posts: 633	Originally posted by Photomy Mr. Mabo mentioned in an earlier post I saw about the need to make changes to any lenses that will use the new real time contrast detect AF sytem and only SDM line will be adaptable. Anyone care to speculate if the 60-250 which was just released was already designed to use the new contrast detect AF system? Maybe this was already answered - I could not find it. - Tom The marketing of this lens took longer than we expected just to insure that it would be compatible, I think.

05-08-2009, 04:14 PM	#3
Photomy Senior Member Join Date: Jan 2007 Location: Kansas City, MO Posts: 174 Original Poster	I hope so. With the 60-250 I can get by with just 3 lenses for 90% of my shots. I like the concept of the K-7 from what I hear about is so far from unofficial information. Not sure how much I would use video, but you never know what opportunities it may bring. I hope Pentax comes in with a winner so I can afford to keep my RZii kit and still do some film.

05-09-2009, 01:21 AM	#4
RMabo Veteran Member Join Date: Jul 2007 Location: Sweden Posts: 845	For optimum performance of the contrast detect AF, lenses needs prepared prepared focus motors (do note that Olympus has issued upgrades for their existing lenses to give better functionality with contrast detect AF) or they will focus slower than what is actually possible with the system. The 60-250 has been delayed so long and when it comes now I would be surprised if it wasn't designed with "the new K" in mind since 60-250 would propably be a popular choice among the target users for "the new K".

05-09-2009, 04:08 AM	#5
lol101 Veteran Member Join Date: Jul 2007 Location: Garennes sur Eure France Photos: Gallery Posts: 899	Originally posted by RMabo For optimum performance of the contrast detect AF, lenses needs prepared prepared focus motors (do note that Olympus has issued upgrades for their existing lenses to give better functionality with contrast detect AF) or they will focus slower than what is actually possible with the system. The 60-250 has been delayed so long and when it comes now I would be surprised if it wasn't designed with "the new K" in mind since 60-250 would propably be a popular choice among the target users for "the new K". Do you think older SDM lenses can be upgraded so than people that have just bought DA* lenses can benefit from these advances?

05-09-2009, 04:42 AM	#6
zntgrg Senior Member Join Date: Oct 2007 Location: Verona, Italy Posts: 202	I think Olympus lenses needed update because they actually have a firmware [i.e. some software on it]: i don't see why a normal electric motor shouldn't be precise and fast enough.

05-09-2009, 06:30 PM	#7
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	Originally posted by lol101 Do you think older SDM lenses can be upgraded so than people that have just bought DA* lenses can benefit from these advances? so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF.

05-10-2009, 01:53 AM	#8
lol101 Veteran Member Join Date: Jul 2007 Location: Garennes sur Eure France Photos: Gallery Posts: 899	Originally posted by deejjjaaaa so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF. That would also include the 60-250 in that case. AFAIK, this lens features the same AF mechanism that previous ones. Plus, if SDM is inherently too slow for fast CDAF, what can possibly do Pentax to claim that they needed to upgrade lenses? They certainly did not upgrade them to ring USM did they?

05-10-2009, 02:24 AM	#9
nosnoop Veteran Member Join Date: Feb 2007 Posts: 1,299	Originally posted by deejjjaaaa so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF. Another pure speculation? There is no reason why micromotors cannot be made to be as fast as ring type.

05-10-2009, 05:45 AM	#10
vinzer Veteran Member Join Date: Mar 2007 Location: Philippines Posts: 1,399	Originally posted by deejjjaaaa so far all Pentax SDM are micromotors (essentially screw drive with the motor located in lens' body instead of camera's body), not ring type motors, so they are too slow to ensure a fast CDAF. I still think the chokepoint is still in the AF algorithms in place than the hardware itself. Non-ring type Canon lenses are still able performers in AF speed. Not world-beating speed, but still capable.

05-10-2009, 07:54 AM	#11
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	Originally posted by nosnoop Another pure speculation? There is no reason why micromotors cannot be made to be as fast as ring type. the only speculation here is underlined above

05-10-2009, 08:02 AM	#12
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	Originally posted by vinzer I still think the chokepoint is still in the AF algorithms in place than the hardware itself. Non-ring type Canon lenses are still able performers in AF speed. Not world-beating speed, but still capable. yes, performers - with PDAF - where you can predict where to move and calculate how much you will need to move the focusing group of optical elements with one measurement... one measurement - one movement (some systems are doing double check though)... now enters CDAF where this is not possible (you need several iterations) and put on top of that AF-C... as for performers, sure - we even have screw driven lenses that can focus fast... with PDAF

05-11-2009, 10:27 AM	#13
Asahiflex Pentaxian Join Date: Jan 2008 Location: Netherlands Photos: Gallery Posts: 2,795	FWIW: the lens was tested on a Pentax MZ-5n and it appears to be fullframe. See here for the results: Pentax 60-250 SDM Samples: Pentax SLR Talk Forum: Digital Photography Review

06-09-2009, 08:04 AM	#14
Xian Junior Member Join Date: Jun 2009 Location: South Korea Posts: 33	Won´t screw driven on body motor support contrast AF?? Why...??

06-09-2009, 08:27 AM	#15
and Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 2,476	it will. I consider it just a myth that the 60-250 was delayed for some special reason, codiac2600 also mentioned this that "they had plans for it" but I see no special reason why the 60-250 should be delayed it doesnt have any special feature that the other DA* has