damaged autofocus?

gizi · 07-31-2009, 09:20 AM

hello there! this is my first post but sadly I come with a concern...

I have a pentax k20d + sigma apo 70-300 lens that were borrowed for a few hours to a friend of mine. this was all good until he said that he manually turned the autofocus ring when the camera was on SAF (autofocus).

he only turned it when the autofocus was set at the point he wanted not turning the lens one way while it's trying to autofocus in the other.

I know that this isn't OK but what can I say now...so I come to ask you guys for some opinions... Do I have a problem now? How does the AF motor brake or what are the "symptoms" or how could I test the autofocus if it is still running normal?

From what I tested the autofocus still works fine but I have a feeling of frustration about this because I'm no expert...

can somebody help me with some suggestions?

Thanks

Last edited by gizi; 07-31-2009 at 10:10 AM.

wildlifephotog · 07-31-2009, 10:06 AM

Had my wife do that once. Never again.

It should be OK.
I wouldn't make it a habit though. And don't loan it to folks that don't know what they are doing.

ytterbium · 07-31-2009, 10:24 AM

This is very obvious scenario that could happen with directly coupled AF.
If the camera was designed for real people and by people who are not completely dumb such possibility should have been foreseen. But have a quick look trough the manual - it is always cheaper to write what you can't do, than designing it such way you can't do it.
So thinking logically, camera might not like it too much (like draining excessively at that moment batteries, wearing out gears faster - if done often) but should handle it without damage.

Sometimes i even wonder why Pentax didn't included some clutch system in the body - it could not be full time, since the clutch would release heavy lenses - it would only "release" the lens when the camera is not focussing and delay/cancel AF if the lens is being turned at the moment of half shutter press.

The lens is another story, where the camera dosn't know anything about it's state and just keeps it turning as hard as it can. Even if the camera might be safe against such actions the lens may be not (especially such as Sigma which isn't designed exclusively for Pentax AF system, but only adapted to it).

gizi · 07-31-2009, 10:41 AM

thanks for the replies guys! I bought the camera just 2 months ago so I guess that the gears are like new...
the thing is that my friend had some time to try the " new mode SAF-manual" and from what he said, he turned the ring about 10-15 times. So, from what I understood, I can relax about this problem right? with the mentioning to not do this again and to decrease my friends

.
ytterbium...from what I know the sigma HSM lenses have a clutch...
oh, and the sigma apo still works normal...

octavmandru · 07-31-2009, 10:49 AM

If camera is not making strange noise like grinding or any irregular sound, relax.
Cameras, horses and wives are no loaners. At least on my list.

gizi · 07-31-2009, 11:02 AM

no, no strange noises. the camera sounds exactly the same as before...

Quote:

Cameras, horses and wives are no loaners. At least on my list.

Yes, I learned my lesson.

my last question...I guess the autofocus speed can't be affected by this, right?

Pentaxor · 07-31-2009, 09:06 PM

never lend your camera to anyone unless that person is familiar to that particular equipment.

gizi · 08-01-2009, 12:41 AM

yes, I got that idea. I'm now a bit concerned of maybe the autofocus speed and quality was affected by this...or in this case it's a simple answer? if it didn't brake it is like normal...but if it brake you can say bye bye to the camera. am I right? sorry for the idiot questions but I only started photography for a few months and I want to know if my camera is OK or if I have to go to repair it.

res3567 · 08-01-2009, 02:11 AM

Originally posted by gizi

yes, I got that idea. I'm now a bit concerned of maybe the autofocus speed and quality was affected by this...or in this case it's a simple answer? if it didn't brake it is like normal...but if it brake you can say bye bye to the camera. am I right? sorry for the idiot questions but I only started photography for a few months and I want to know if my camera is OK or if I have to go to repair it.

Take the camera in an outdoor of bright light setting and see how quickly it locks on focus. If it seems to be working as before, then you will probably alright.

You can always send it in for a check, but if it works like it did before you lent it out, then I would not worry about it.

You know how the camera behaved before this right? Compare it now.

The reason why I say outdoor or bright light is because Pentax DSLR's ( not including the new K7) have a history of moderate to poor low light autofocus performance.

Mine are no exception and don't let that be a reason to believe the camera is broken if has trouble locking in low light.

gizi · 08-01-2009, 05:10 AM

well, I checked that and from what I remember the focus speed is the same with the 18-55 as well as with the sigma apo (meaning that is still pretty fast under good light). in low light conditions yes it's somehow slow but exactly like before (both of them). so I think I'm ok and no damage was made to the camera...
Thanks to all that responded!

mickeyobe · 08-01-2009, 06:32 AM

Never lend your camera to ANYONE.

Mickey

07-31-2009, 09:20 AM	#1
gizi New Member Join Date: Jul 2009 Posts: 7	damaged autofocus? hello there! this is my first post but sadly I come with a concern... I have a pentax k20d + sigma apo 70-300 lens that were borrowed for a few hours to a friend of mine. this was all good until he said that he manually turned the autofocus ring when the camera was on SAF (autofocus). he only turned it when the autofocus was set at the point he wanted not turning the lens one way while it's trying to autofocus in the other. I know that this isn't OK but what can I say now...so I come to ask you guys for some opinions... Do I have a problem now? How does the AF motor brake or what are the "symptoms" or how could I test the autofocus if it is still running normal? From what I tested the autofocus still works fine but I have a feeling of frustration about this because I'm no expert... can somebody help me with some suggestions? Thanks Last edited by gizi; 07-31-2009 at 10:10 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Is my K7 damaged?	kuau	Pentax DSLR Discussion	16	06-17-2010 07:17 PM
Help! Autofocus switch stuck on AF.S and will not autofocus!	pauldiebel	Pentax DSLR Discussion	3	09-19-2009 08:59 PM
Damaged Display	TSuppa	Pentax DSLR Discussion	1	10-29-2008 06:33 PM
For Sale - Sold: FS: Autofocus film cameras and autofocus lenses	Not Registered	Sold Items	15	03-17-2008 07:08 AM
In-Body autofocus vs In-Lens autofocus	Gooshin	Pentax DSLR Discussion	7	02-05-2008 11:10 AM

07-31-2009, 10:06 AM	#2
wildlifephotog Inactive Account Join Date: Nov 2008 Location: USA Posts: 924	Had my wife do that once. Never again. It should be OK. I wouldn't make it a habit though. And don't loan it to folks that don't know what they are doing.

07-31-2009, 10:24 AM	#3
ytterbium Veteran Member Join Date: Jan 2008 Posts: 1,076	This is very obvious scenario that could happen with directly coupled AF. If the camera was designed for real people and by people who are not completely dumb such possibility should have been foreseen. But have a quick look trough the manual - it is always cheaper to write what you can't do, than designing it such way you can't do it. So thinking logically, camera might not like it too much (like draining excessively at that moment batteries, wearing out gears faster - if done often) but should handle it without damage. Sometimes i even wonder why Pentax didn't included some clutch system in the body - it could not be full time, since the clutch would release heavy lenses - it would only "release" the lens when the camera is not focussing and delay/cancel AF if the lens is being turned at the moment of half shutter press. The lens is another story, where the camera dosn't know anything about it's state and just keeps it turning as hard as it can. Even if the camera might be safe against such actions the lens may be not (especially such as Sigma which isn't designed exclusively for Pentax AF system, but only adapted to it).

07-31-2009, 10:41 AM	#4
gizi New Member Join Date: Jul 2009 Posts: 7 Original Poster	thanks for the replies guys! I bought the camera just 2 months ago so I guess that the gears are like new... the thing is that my friend had some time to try the " new mode SAF-manual" and from what he said, he turned the ring about 10-15 times. So, from what I understood, I can relax about this problem right? with the mentioning to not do this again and to decrease my friends . ytterbium...from what I know the sigma HSM lenses have a clutch... oh, and the sigma apo still works normal...

07-31-2009, 10:49 AM	#5
octavmandru Veteran Member Join Date: Jan 2009 Location: somewhere around Posts: 615	If camera is not making strange noise like grinding or any irregular sound, relax. Cameras, horses and wives are no loaners. At least on my list.

07-31-2009, 11:02 AM	#6
gizi New Member Join Date: Jul 2009 Posts: 7 Original Poster	no, no strange noises. the camera sounds exactly the same as before... Quote: Cameras, horses and wives are no loaners. At least on my list. Yes, I learned my lesson. my last question...I guess the autofocus speed can't be affected by this, right?

07-31-2009, 09:06 PM	#7
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	never lend your camera to anyone unless that person is familiar to that particular equipment.

08-01-2009, 12:41 AM	#8
gizi New Member Join Date: Jul 2009 Posts: 7 Original Poster	yes, I got that idea. I'm now a bit concerned of maybe the autofocus speed and quality was affected by this...or in this case it's a simple answer? if it didn't brake it is like normal...but if it brake you can say bye bye to the camera. am I right? sorry for the idiot questions but I only started photography for a few months and I want to know if my camera is OK or if I have to go to repair it.

08-01-2009, 02:11 AM	#9
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by gizi yes, I got that idea. I'm now a bit concerned of maybe the autofocus speed and quality was affected by this...or in this case it's a simple answer? if it didn't brake it is like normal...but if it brake you can say bye bye to the camera. am I right? sorry for the idiot questions but I only started photography for a few months and I want to know if my camera is OK or if I have to go to repair it. Take the camera in an outdoor of bright light setting and see how quickly it locks on focus. If it seems to be working as before, then you will probably alright. You can always send it in for a check, but if it works like it did before you lent it out, then I would not worry about it. You know how the camera behaved before this right? Compare it now. The reason why I say outdoor or bright light is because Pentax DSLR's ( not including the new K7) have a history of moderate to poor low light autofocus performance. Mine are no exception and don't let that be a reason to believe the camera is broken if has trouble locking in low light.

08-01-2009, 05:10 AM	#10
gizi New Member Join Date: Jul 2009 Posts: 7 Original Poster	well, I checked that and from what I remember the focus speed is the same with the 18-55 as well as with the sigma apo (meaning that is still pretty fast under good light). in low light conditions yes it's somehow slow but exactly like before (both of them). so I think I'm ok and no damage was made to the camera... Thanks to all that responded!

08-01-2009, 06:32 AM	#11
mickeyobe Veteran Member Join Date: Dec 2006 Location: Toronto, Ontario, Canada Posts: 1,759	Never lend your camera to ANYONE. Mickey