Pentax-FA SMC 28-105 F4-5.6 power zoom

Hope9811 · 07-01-2013, 05:59 PM

I just bought the power zoom version of this lens and I can't get it to work on my K-x.... anyone know why? It doesn't seem to "focus" on anything whether I use the power zoom or not. It also has an infinity sign on the showing in the top and it has a button on the side that I can't find any information at all about. It says "P A AS" any ideas of why this isn't working on the K-x? I was excited to find this lens because it's rated fairly well on the lens review and I wanted a little more distance than the 18-55 kit lens but it doesn't seem to focus on anything except landscapes.... any ideas?

Adam · 07-01-2013, 06:05 PM

Originally posted by Hope9811

I just bought the power zoom version of this lens and I can't get it to work on my K-x.... anyone know why? It doesn't seem to "focus" on anything whether I use the power zoom or not. It also has an infinity sign on the showing in the top and it has a button on the side that I can't find any information at all about. It says "P A AS" any ideas of why this isn't working on the K-x? I was excited to find this lens because it's rated fairly well on the lens review and I wanted a little more distance than the 18-55 kit lens but it doesn't seem to focus on anything except landscapes.... any ideas?

Power zoom will only work with the K10D, K20D, K-7, and K-5/II/IIs. Slide the ring back and you'll be able to zoom normally

Hope9811 · 07-01-2013, 08:12 PM

Originally posted by Adam

Power zoom will only work with the K10D, K20D, K-7, and K-5/II/IIs. Slide the ring back and you'll be able to zoom normally

I tried that ... it will sound like it's pulsing...not necessarily a focusing sound ... more of a pulsing sound then it will make my flash shoot a small distance.... but it doesn't focus. Strange... I think there might be something wrong with this particular lens..... I've been playing with it again and still nothing.... I'm a little concerned that it makes the flash do strange things as I don't want to short out my camera if this is even possible.... is it? LOL.

Adam · 07-01-2013, 08:16 PM

Originally posted by Hope9811

I tried that ... it will sound like it's pulsing...not necessarily a focusing sound ... more of a pulsing sound then it will make my flash shoot a small distance.... but it doesn't focus. Strange... I think there might be something wrong with this particular lens..... I've been playing with it again and still nothing.... I'm a little concerned that it makes the flash do strange things as I don't want to short out my camera if this is even possible.... is it? LOL.

Well, the power zoom and the focusing are two separate systems. Sounds like there might be something wrong with the lens, either that or you need to make sure that it's mounted properly.

Adam
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**Just1MoreDave** · 07-01-2013, 08:44 PM

The button on the side is for some power zoom features - I don't think any of these features are supported on any DSLR. I don't know a lot about that switch because mine was broken off when I got the lens.

Have you tried manual focus, or even turning the focus ring with the lens off the camera? The window where you see the infinity symbol should show a scale that has a flower at the other end.

The zoom ring will show the words POWER ZOOM on its power zoom position, turn only about 30 degrees left or right and center itself when released. In the manual zoom position it should rotate like any other zoom.

**RKKS08** · 07-04-2013, 06:15 PM

The "P A AS" functions will not work with your camera. And even with DSLRs supporting power zoom, not all PZ functions may work. I think, only the Z/PZ1 and MZ-S did support all functions.

If you still are interested to know about all the functions of that switch (and the button beneath), have a look at the english speaking section of the Photo-net forum (I hope I am allowed to set a link to an at least partially competing forum):

Function of P-A-AS in Pentax Power Zoom lenses - Photo.net Pentax Forum

There a user explains it in detail.

EDIT:
I must correct my statement in respect to compatibility with Pentax film bodies.

It seems every Z/PZ body supports all power zoom functions.
But of the MZ/ZX series, some don't.

07-01-2013, 05:59 PM	#1
Hope9811 Junior Member Join Date: Jun 2013 Posts: 46	Pentax-FA SMC 28-105 F4-5.6 power zoom I just bought the power zoom version of this lens and I can't get it to work on my K-x.... anyone know why? It doesn't seem to "focus" on anything whether I use the power zoom or not. It also has an infinity sign on the showing in the top and it has a button on the side that I can't find any information at all about. It says "P A AS" any ideas of why this isn't working on the K-x? I was excited to find this lens because it's rated fairly well on the lens review and I wanted a little more distance than the 18-55 kit lens but it doesn't seem to focus on anything except landscapes.... any ideas?

07-01-2013, 06:05 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,597	Originally posted by Hope9811 I just bought the power zoom version of this lens and I can't get it to work on my K-x.... anyone know why? It doesn't seem to "focus" on anything whether I use the power zoom or not. It also has an infinity sign on the showing in the top and it has a button on the side that I can't find any information at all about. It says "P A AS" any ideas of why this isn't working on the K-x? I was excited to find this lens because it's rated fairly well on the lens review and I wanted a little more distance than the 18-55 kit lens but it doesn't seem to focus on anything except landscapes.... any ideas? Power zoom will only work with the K10D, K20D, K-7, and K-5/II/IIs. Slide the ring back and you'll be able to zoom normally Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

07-04-2013, 06:15 PM	#6
RKKS08 Site Supporter Join Date: Mar 2010 Location: Frankfurt am Main Posts: 1,241	The "P A AS" functions will not work with your camera. And even with DSLRs supporting power zoom, not all PZ functions may work. I think, only the Z/PZ1 and MZ-S did support all functions. If you still are interested to know about all the functions of that switch (and the button beneath), have a look at the english speaking section of the Photo-net forum (I hope I am allowed to set a link to an at least partially competing forum): Function of P-A-AS in Pentax Power Zoom lenses - Photo.net Pentax Forum There a user explains it in detail. EDIT: I must correct my statement in respect to compatibility with Pentax film bodies. It seems every Z/PZ body supports all power zoom functions. But of the MZ/ZX series, some don't. Last edited by RKKS08; 07-04-2013 at 06:35 PM.

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07-01-2013, 08:12 PM	#3
Hope9811 Junior Member Join Date: Jun 2013 Posts: 46 Original Poster	Originally posted by Adam Power zoom will only work with the K10D, K20D, K-7, and K-5/II/IIs. Slide the ring back and you'll be able to zoom normally I tried that ... it will sound like it's pulsing...not necessarily a focusing sound ... more of a pulsing sound then it will make my flash shoot a small distance.... but it doesn't focus. Strange... I think there might be something wrong with this particular lens..... I've been playing with it again and still nothing.... I'm a little concerned that it makes the flash do strange things as I don't want to short out my camera if this is even possible.... is it? LOL.

07-01-2013, 08:16 PM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,597	Originally posted by Hope9811 I tried that ... it will sound like it's pulsing...not necessarily a focusing sound ... more of a pulsing sound then it will make my flash shoot a small distance.... but it doesn't focus. Strange... I think there might be something wrong with this particular lens..... I've been playing with it again and still nothing.... I'm a little concerned that it makes the flash do strange things as I don't want to short out my camera if this is even possible.... is it? LOL. Well, the power zoom and the focusing are two separate systems. Sounds like there might be something wrong with the lens, either that or you need to make sure that it's mounted properly. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

07-01-2013, 08:44 PM	#5
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	The button on the side is for some power zoom features - I don't think any of these features are supported on any DSLR. I don't know a lot about that switch because mine was broken off when I got the lens. Have you tried manual focus, or even turning the focus ring with the lens off the camera? The window where you see the infinity symbol should show a scale that has a flower at the other end. The zoom ring will show the words POWER ZOOM on its power zoom position, turn only about 30 degrees left or right and center itself when released. In the manual zoom position it should rotate like any other zoom.