How to deactivate SDM and allow for screw drive autofocus with DA* 16-50mm f/2.8
Posted 02/01/2013 - 12:28
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Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
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Posted 02/01/2013 - 12:36
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cabstar wrote:
Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
You are still looking at well over £100 for an SDM repair?Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
If you haven't got the money then this at least gives you af capability. I believe that screw drive on these 2 lenses is also quite a bit faster than SDM ... I might even consider the 50-135mm again (and sell the Sigma 50-150mm) if I could bypass SDM.
Posted 02/01/2013 - 14:09
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Last quote I had was around £125 and that was with the new upgraded parts
When I compared my 50-135 on an old k110d (screwdrive) to my GX20 focus speed there was very little difference in AF speed. I think the noise of screwdrive creates an impression of speed.
Here are some shaky videos I made at the time
Screwdrive
SDM
When I compared my 50-135 on an old k110d (screwdrive) to my GX20 focus speed there was very little difference in AF speed. I think the noise of screwdrive creates an impression of speed.
Here are some shaky videos I made at the time
Screwdrive
SDM
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Currently on a Pentax hiatus until an FF Pentax is released
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Currently on a Pentax hiatus until an FF Pentax is released
Posted 02/01/2013 - 14:17
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cabstar wrote:
Last quote I had was around £125 and that was with the new upgraded parts
When I compared my 50-135 on an old k110d (screwdrive) to my GX20 focus speed there was very little difference in AF speed. I think the noise of screwdrive creates an impression of speed.
Here are some shaky videos I made at the time
Screwdrive
SDM
£125 is a lot to some people so screw drive is still better than manual focus. Also AF speed was "supposedly" much improved with the K-7/K-5 .. I know some of my screw drive lenses were/are faster on those 2 bodies when compared with the K10D.
Last quote I had was around £125 and that was with the new upgraded parts
When I compared my 50-135 on an old k110d (screwdrive) to my GX20 focus speed there was very little difference in AF speed. I think the noise of screwdrive creates an impression of speed.
Here are some shaky videos I made at the time
Screwdrive
SDM
Posted 02/01/2013 - 14:21
Link
Didn't SDM speed also improve on the k-7 / k-5 too???
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Currently on a Pentax hiatus until an FF Pentax is released
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Currently on a Pentax hiatus until an FF Pentax is released
Posted 02/01/2013 - 14:53
Link
cabstar wrote:
Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
I do understand your point of view. It is obvious That the Best choice is to repair the Lens, but there are many situations where you might consider bot using sdm .Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
For example, the cost of reparing, using a converter, the lack of time to sens the Lens for repair it, an already failed sdm, etc...
In thèse cases, thé double af possibilities of thé Lens might be usefull
Posted 02/01/2013 - 15:06
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cabstar wrote:
Didn't SDM speed also improve on the k-7 / k-5 too???
If it did I never noticed it on the 50-135mm.Didn't SDM speed also improve on the k-7 / k-5 too???
As I understand it the limiting factor (with regard to AF speed) of SDM lenses is the lens motor itself, hence why the 18-135mm (DC motor) is much faster
Posted 02/01/2013 - 15:22
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As I noticed that very first producted 16-50mm have a slower but smoother SDM than latter ones. ( I had a very first 16-50mm avaible in France and since, I broke it, exchange for a second with SDM failure, repaired and I tried more than 5 16-50mm during a sale I made by spliting K20, 50-135 and 16-50mm before the price increasing tiume)
Posted 02/01/2013 - 16:28
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Mike-P wrote:
As I understand it the limiting factor (with regard to AF speed) of SDM lenses is the lens motor itself, hence why the 18-135mm (DC motor) is much faster
Is there a different motor in the 18-135 then???
cabstar wrote:
Didn't SDM speed also improve on the k-7 / k-5 too???
If it did I never noticed it on the 50-135mm.Didn't SDM speed also improve on the k-7 / k-5 too???
As I understand it the limiting factor (with regard to AF speed) of SDM lenses is the lens motor itself, hence why the 18-135mm (DC motor) is much faster
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Currently on a Pentax hiatus until an FF Pentax is released
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Currently on a Pentax hiatus until an FF Pentax is released
Posted 02/01/2013 - 16:31
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clover wrote:
For example, the cost of reparing, using a converter, the lack of time to sens the Lens for repair it, an already failed sdm, etc...
In thèse cases, thé double af possibilities of thé Lens might be usefull
Hmm the use of a teleconverter is a good idea for longer glass maybe the 300mm f/4
cabstar wrote:
Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
I do understand your point of view. It is obvious That the Best choice is to repair the Lens, but there are many situations where you might consider bot using sdm .Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
For example, the cost of reparing, using a converter, the lack of time to sens the Lens for repair it, an already failed sdm, etc...
In thèse cases, thé double af possibilities of thé Lens might be usefull
PPG Wedding photography Flickr
Concert photography
Currently on a Pentax hiatus until an FF Pentax is released
Concert photography
Currently on a Pentax hiatus until an FF Pentax is released
Posted 02/01/2013 - 16:49
Link
Quote:
Is there a different motor in the 18-135 then???
Yes, it uses a different DC motor.
Is there a different motor in the 18-135 then???
Best regards, John
Posted 02/01/2013 - 17:23
Link
cabstar wrote:
I sold my 300mm DA for a 300mm FA 4.5 so I can use AF with a converter.clover wrote:
For example, the cost of reparing, using a converter, the lack of time to sens the Lens for repair it, an already failed sdm, etc...
In thèse cases, thé double af possibilities of thé Lens might be usefull
Hmm the use of a teleconverter is a good idea for longer glass maybe the 300mm f/4cabstar wrote:
Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
I do understand your point of view. It is obvious That the Best choice is to repair the Lens, but there are many situations where you might consider bot using sdm .Why???
All those lenses will work with screw drive only bodies, if its to get around a broken SDM lens then repairs with the newer parts can be done fairly reasonably.
I don't see the point of this...
For example, the cost of reparing, using a converter, the lack of time to sens the Lens for repair it, an already failed sdm, etc...
In thèse cases, thé double af possibilities of thé Lens might be usefull
I will try to get the lens rom from a 300mm as soon as I can
Posted 02/01/2013 - 18:46
Link
johnriley wrote:
Is that unique to that lens John?
Quote:
Is there a different motor in the 18-135 then???
Yes, it uses a different DC motor.Is there a different motor in the 18-135 then???
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Concert photography
Currently on a Pentax hiatus until an FF Pentax is released
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Currently on a Pentax hiatus until an FF Pentax is released
Posted 02/01/2013 - 18:56
Link
cabstar wrote:
Yes, I think so. I was actually expecting the new 18-270mm to be a DC motor as well, but that one is marked up as SDM.
johnriley wrote:
Is that unique to that lens John?Quote:
Is there a different motor in the 18-135 then???
Yes, it uses a different DC motor.Is there a different motor in the 18-135 then???
Best regards, John
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17 posts
14 years
For the 16-50mm
http://www.pentaxiste.org/pratique/depannage/article/how-to-deactivate-sdm-and-a...
For the 50-135mm
http://www.pentaxiste.org/pratique/depannage/article/how-to-deactivate-sdm-and-a...