LENS HELP: Auto Focus & A-Setting of Aperture Doesn't Function

richard balonglong · 06-29-2012, 07:45 AM

Hello fellow Pentaxians..!

Anyone knows how to troubleshoot a lens problem?
Here's the problem:
I have a Tokina 28-70mm f2.6-2.8 at-x pro lens, it was working perfectly on all of my Pentax DSLRs. One day, I got caught in a strong rain, and the lens got some rain water, but I'm not sure that the lens was got really soaked because I protected it with cloth and with some plastic.
So, after two days, suddenly the lens' auto focus and the A-setting of aperture doesn't work. I know that it's not a camera error because my other auto focus lenses works perfectly on my Pentax K-7. Anyway, If I install the Tokina 28-70mm on the camera, switch it on, then the focal length selector appears as if I were installing a full manual lens. It seamed that the lens' contacts/electronics got a problem. I tried to dry the lens' aperture ring for days (even used a hair dryer then pointed it at the aperture ring area) because I thought it might had a soaked parts inside, but still the AF and A-setting of aperture doesn't work. Good thing that I can still use the lens but in full manual control, manual focus and manual aperture using the aperture ring...
Anyone had an experience with this kind of problem and solved it?
I'm thinking to ship the lens for repair, but before doing that, I'm thinking that it might be a solvable problem with DIY or has some simple solutions for it...

Thank you in advance!
Richard B.

Last edited by richard balonglong; 06-29-2012 at 08:02 AM.

adpo · 06-29-2012, 08:38 AM

you might have a shorted circuit board, in which case you're pretty much out of luck. good luck with the lens, hopefully its some other ailment

espofoto · 08-17-2012, 11:04 AM

I'm sorry about your lens. I hope that by now you have solved the problem, but I'm guessing that it needs a trip to the repairman. BTW, is the RC-1 that you had advertised sold? If not please send me a PM.

screwdriver222 · 08-17-2012, 11:08 AM

I would give the contacts a good clean

MysteryOnion · 08-17-2012, 11:56 AM

Did you pack the lens in Silica gel packs or if not handy, bag of rice? Deeper in is a challenge to dry out. Rice, for example, cured my tv remote of the horrible soaking it received... tall glass of water for over an hour. Later when I had time, I took it apart to see how well the rice worked and it seemed to have pull water out even from between the membrane and contact board... worth trying if you have some time. A bag of rice twice the volume of the lens should be enough. If Silica gel, about 1/4 the volume is more than enough. Seal it in a bag. Good luck?

06-29-2012, 07:45 AM	#1
richard balonglong Veteran Member Join Date: Aug 2007 Location: Baguio City, Philippines Photos: Gallery Posts: 350	LENS HELP: Auto Focus & A-Setting of Aperture Doesn't Function Hello fellow Pentaxians..! Anyone knows how to troubleshoot a lens problem? Here's the problem: I have a Tokina 28-70mm f2.6-2.8 at-x pro lens, it was working perfectly on all of my Pentax DSLRs. One day, I got caught in a strong rain, and the lens got some rain water, but I'm not sure that the lens was got really soaked because I protected it with cloth and with some plastic. So, after two days, suddenly the lens' auto focus and the A-setting of aperture doesn't work. I know that it's not a camera error because my other auto focus lenses works perfectly on my Pentax K-7. Anyway, If I install the Tokina 28-70mm on the camera, switch it on, then the focal length selector appears as if I were installing a full manual lens. It seamed that the lens' contacts/electronics got a problem. I tried to dry the lens' aperture ring for days (even used a hair dryer then pointed it at the aperture ring area) because I thought it might had a soaked parts inside, but still the AF and A-setting of aperture doesn't work. Good thing that I can still use the lens but in full manual control, manual focus and manual aperture using the aperture ring... Anyone had an experience with this kind of problem and solved it? I'm thinking to ship the lens for repair, but before doing that, I'm thinking that it might be a solvable problem with DIY or has some simple solutions for it... Thank you in advance! Richard B. Last edited by richard balonglong; 06-29-2012 at 08:02 AM.

08-17-2012, 11:04 AM	#3
espofoto New Member Join Date: Aug 2012 Posts: 2	RC-1 I'm sorry about your lens. I hope that by now you have solved the problem, but I'm guessing that it needs a trip to the repairman. BTW, is the RC-1 that you had advertised sold? If not please send me a PM.

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06-29-2012, 08:38 AM	#2
adpo Veteran Member Join Date: Apr 2011 Location: Arizona Photos: Gallery Posts: 888	you might have a shorted circuit board, in which case you're pretty much out of luck. good luck with the lens, hopefully its some other ailment

08-17-2012, 11:08 AM	#4
screwdriver222 Senior Member Join Date: Oct 2011 Location: Plymouth Photos: Gallery \| Albums Posts: 139	I would give the contacts a good clean

08-17-2012, 11:56 AM	#5
MysteryOnion Giveaway winner! Join Date: Dec 2007 Location: beantown Photos: Albums Posts: 944	Did you pack the lens in Silica gel packs or if not handy, bag of rice? Deeper in is a challenge to dry out. Rice, for example, cured my tv remote of the horrible soaking it received... tall glass of water for over an hour. Later when I had time, I took it apart to see how well the rice worked and it seemed to have pull water out even from between the membrane and contact board... worth trying if you have some time. A bag of rice twice the volume of the lens should be enough. If Silica gel, about 1/4 the volume is more than enough. Seal it in a bag. Good luck?

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