Help! AF not working

benroy · 05-28-2011, 06:34 AM

Help! I am using a K5 and just bought a used 300/4.5 SMC F...the AF is not working on the 300..manual focus is fine, images are very sharp, but no AF...motor runs in fits and starts, but lens does not move into focus. I've tried dismounting, remounting the lens...won't work. Is there an incompatibility here that I am not aware of?

Any kind of help would be greatly appreciated...very soon, please. I really like this lens and would prefer not to return it for a refund.

Roy Benson

To be more specific: lens is listed in the Pentaxforum database as an F series lens...entitled 300/4.5 SMC Pentax F ED IF. Lens is considered rare and has a user rating of 10. I'd provide a link, but my link thing isn't working. Hope this helps.
Furthermore, the lens has no AF/MF switch...AF/MF must be activated from the K5 camera body.

Last edited by benroy; 05-28-2011 at 08:44 AM. Reason: more info added

TOUGEFC · 05-28-2011, 06:45 AM

Whats the exact name of the lens?

Mike.P® · 05-28-2011, 07:00 AM

Have you moved the ring round the lens to AF?

Francis · 05-28-2011, 07:04 AM

I guess you have a couple of choices. Call the lens busted and send back for refund, or have it checked/fixed professionally and charge the seller for repairs. Is that the FA* 300mm?

(nice)

Francis · 05-28-2011, 07:05 AM

Originally posted by Mike.P®

Have you moved the ring round the lens to AF?

LOL it would just be as busted if the motor moved while the thing was on MF

selar · 05-28-2011, 07:48 AM

I have one and the motor moves but with difficulty when the ring is set to manual focus. To disable the motor completely the body af switch also has to be set to manual.

Wheatfield · 05-28-2011, 08:01 AM

The F300 has the AF/MF switch built right onto the focus ring, no?
Move the ring forwards gives manual focus, backwards AF (or perhaps opposite, mine isn't at my fingertips at the moment).
Anyway, I'd try moving the ring back and forth a few times to see if I couldn't get it to start engaging the AF drive properly.
Otherwise it's repair time.

benroy · 05-28-2011, 08:48 AM

Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime lens.

Roy Benson

JeffJS · 05-28-2011, 09:57 AM

Is it This type of lens? (I know the FL is different)

The focus ring pushes one way for Manual focus and the other way for Auto focus. That is the Lens AF/MF switch people are referring to.

Wheatfield · 05-28-2011, 11:40 AM

Originally posted by benroy

Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime lens.

Roy Benson

A link would be nice. I'll help if I can, but I'm not going to dig around in the database doing what you should be doing.

Ok, the ring behind the focusing ring moves forwards and backwards to switch from AF to MF. If you can't see the words Auto Focus printed on top of the lens, you have the lens in manual focus.

Mike.P® · 05-28-2011, 02:46 PM

Originally posted by benroy

Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime

Arrow points to AF/MF switch/ring .. click it forward and backwards for focus.

benroy · 05-28-2011, 06:11 PM

Thanks, Mike...never thought to try that ring...greatly appreciate your timely message...problem solved.

Roy Benson

05-28-2011, 06:34 AM	#1
benroy Senior Member Join Date: Mar 2011 Location: Boca Raton, Florida Posts: 104	Help! AF not working Help! I am using a K5 and just bought a used 300/4.5 SMC F...the AF is not working on the 300..manual focus is fine, images are very sharp, but no AF...motor runs in fits and starts, but lens does not move into focus. I've tried dismounting, remounting the lens...won't work. Is there an incompatibility here that I am not aware of? Any kind of help would be greatly appreciated...very soon, please. I really like this lens and would prefer not to return it for a refund. Roy Benson To be more specific: lens is listed in the Pentaxforum database as an F series lens...entitled 300/4.5 SMC Pentax F ED IF. Lens is considered rare and has a user rating of 10. I'd provide a link, but my link thing isn't working. Hope this helps. Furthermore, the lens has no AF/MF switch...AF/MF must be activated from the K5 camera body. Last edited by benroy; 05-28-2011 at 08:44 AM. Reason: more info added

05-28-2011, 08:48 AM	#8
benroy Senior Member Join Date: Mar 2011 Location: Boca Raton, Florida Posts: 104 Original Poster	Non AF for 300 Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime lens. Roy Benson

05-28-2011, 11:40 AM	#10
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,991	Originally posted by benroy Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime lens. Roy Benson A link would be nice. I'll help if I can, but I'm not going to dig around in the database doing what you should be doing. Ok, the ring behind the focusing ring moves forwards and backwards to switch from AF to MF. If you can't see the words Auto Focus printed on top of the lens, you have the lens in manual focus. Last edited by Wheatfield; 05-28-2011 at 12:52 PM.

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05-28-2011, 06:45 AM	#2
TOUGEFC Veteran Member Join Date: Nov 2009 Location: Brisbane Photos: Gallery Posts: 3,561	Whats the exact name of the lens?

05-28-2011, 07:00 AM	#3
Mike.P® Veteran Member Join Date: Mar 2008 Location: New Milton, Hampshire, UK Photos: Gallery \| Albums Posts: 2,154	Have you moved the ring round the lens to AF?

05-28-2011, 07:04 AM	#4
Francis Senior Member Join Date: May 2010 Location: Hilversum Photos: Gallery Posts: 215	I guess you have a couple of choices. Call the lens busted and send back for refund, or have it checked/fixed professionally and charge the seller for repairs. Is that the FA* 300mm? (nice)

05-28-2011, 07:05 AM	#5
Francis Senior Member Join Date: May 2010 Location: Hilversum Photos: Gallery Posts: 215	Originally posted by Mike.P® Have you moved the ring round the lens to AF? LOL it would just be as busted if the motor moved while the thing was on MF

05-28-2011, 07:48 AM	#6
selar Veteran Member Join Date: Jul 2007 Location: Sydney, Australia Photos: Gallery \| Albums Posts: 2,042	I have one and the motor moves but with difficulty when the ring is set to manual focus. To disable the motor completely the body af switch also has to be set to manual.

05-28-2011, 08:01 AM	#7
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,991	The F300 has the AF/MF switch built right onto the focus ring, no? Move the ring forwards gives manual focus, backwards AF (or perhaps opposite, mine isn't at my fingertips at the moment). Anyway, I'd try moving the ring back and forth a few times to see if I couldn't get it to start engaging the AF drive properly. Otherwise it's repair time.

05-28-2011, 09:57 AM	#9
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Is it This type of lens? (I know the FL is different) The focus ring pushes one way for Manual focus and the other way for Auto focus. That is the Lens AF/MF switch people are referring to.

05-28-2011, 02:46 PM	#11
Mike.P® Veteran Member Join Date: Mar 2008 Location: New Milton, Hampshire, UK Photos: Gallery \| Albums Posts: 2,154	Originally posted by benroy Lens has no AF/MF switch...AF/MF must be activated by the K5 body. Lens is listed in the Pentaxforum lens database as an F series prime Arrow points to AF/MF switch/ring .. click it forward and backwards for focus.

05-28-2011, 06:11 PM	#12
benroy Senior Member Join Date: Mar 2011 Location: Boca Raton, Florida Posts: 104 Original Poster	Thanks, Mike...never thought to try that ring...greatly appreciate your timely message...problem solved. Roy Benson