AF problem in K-5

oferreira.andre · 08-11-2016, 10:57 AM

Hello!
I bought and Pentax K-5 with a 12k shutter count. It came with the 18-55 WR, I also have the 35-135 and the 50 f1.7
I have it for few days, but I notice that the photos are a bit soft and threfocus point is on the back..I been trying to AF fine ajustment, but I can't manage to work, even in the max of the ajustment, the focus point still the same in the back. One thing I notice is that in Liveview mode the AF manage to focus correctly, the face and contrast AF detection. And also it looks like the stabilization mode only work the liveview mode too, at least I just notice it the this mode.
How can I manage to resolve this problems?
The firmware is the last one realesed 1.16.
Thank you in advance for your help, best wishes

André

Adam · 08-11-2016, 12:59 PM

Have you used a test chart to measure the degree of AF inaccuracy? It can vary at different focal lengths, though it shouldn't be that big of a deal with the 18-55, since it has a slower aperture and thus a wider DoF than many other lenses.

**kiwi_jono** · 08-11-2016, 01:18 PM

Excuse me for asking the obvious but are you using a fixed point (like centre point) when using phase detect AF rather than letting camera random points?

Also, unlike in lens VR, you will not see the effect of the SR in the viewfinder - it only effects the actual photo.

bm75 · 08-11-2016, 02:26 PM

AF fine tuning could be tricky and dangerous if you don't exactly know what to do. before doing that, try 1 - factory reset of all settings; 2 - check for firmware , eventually make an update to the latest version; 3 - make some tests in good light with the camera on a tripod (try another af lens, different from the 18-55 to see if something changes). after that, if you don't notice a different behaviour in the camera, try the AF fine tune. My experience with K5 is that you need some learning curve to be AF confident . I mostly use center point only , AFS and for critical situation in landscape I check the focusing with liveview magnification. Also remember that AF performance varies due to lens-body combo . I've experienced that AF is quite reliable in center point af in AFS but algorithms for AFC or Auto 11 points are not that reliable.

oferreira.andre · 08-12-2016, 01:46 AM

I am using the center focus point only.

Originally posted by kiwi_jono

Excuse me for asking the obvious but are you using a fixed point (like centre point) when using phase detect AF rather than letting camera random points?

Also, unlike in lens VR, you will not see the effect of the SR in the viewfinder - it only effects the actual photo.

---------- Post added 08-12-16 at 02:03 AM ----------

I been testing just in AFS and using just the center focus point. What I think is weird, is the focus in live view gets pretty sharp in the focus point, with the eyeview gets soft, and focus a little bit in the back. Also the fine ajustment I don't notice any difference in the focus accuracy, if is -10 or +10 is equal (off course this a example, I have been testing smaller steps). I have the last firmware, but I am thinking maybe something went wrong, and maybe I will give a try in 1.15, and check if there is any diference in the AF and in the fine ajustment.
About different lens the problem is the same, the zoom 35-135 or the prime 50mm.

Originally posted by bm75

AF fine tuning could be tricky and dangerous if you don't exactly know what to do. before doing that, try 1 - factory reset of all settings; 2n - check for firmware , eventually make an update to the latest version; 3 - make some tests in good light with the camera on a tripod (try another af lens, different from the 18-55 to see if something changes). after that, if you don't notice a different behaviour in the camera, try the AF fine tune. My experience with K5 is that you need some learning curve to be AF confident . I mostly use center point only , AFS and for critical situation in landscape I check the focusing with liveview magnification. Also remember that AF performance varies due to lens-body combo . I've experienced that AF is quite reliable in center point af in AFS but algorithms for AFC or Auto 11 points are not that reliable.

bm75 · 08-12-2016, 08:08 AM

I'm sorry for that....it's really a strange thing that af fine adj. doesn't work. With my k5 I've never had any necessity to fine calibrate the af (also with DA17-70 that's known for being problematic) but initially I had some problems with the viewfinfìder: I didn't find the correct 0 position (uncorrected diptrics), i solved the problem with the OM-53 magnifier eyecup. Just to say that if you have problems with the viewfinder, you'll never exactly know what the af is guessing to be in focus (with some subjects in my opinion the red af squares are too big to really give the exact idea of what the af focusing in - and APSC viewfinders are small, also if pentax' are really good).
As an exemple of repetitive missing focus in my experience: my k5 af doesn't like to focus small faces in typical family candids with a landscape on the back...no way to solve the problem also in AFS single central point (AFlock and recomposing - that's insidious because the focal plane can shift with wides)...no way to have eyes in focus...I know that and treat it 1- as a mine fault as a bad photographer

: I have to learn composition and make better photos (typically I close the diaphragm to f/8 or more).. 2 - Perhaps af sensors have a sensitive area that's bigger than the relative small part which I want in focus.
Just to say...

oferreira.andre · 08-13-2016, 01:31 AM

Thank you for all the replies, I will try a pair of changes and do some more test,and let you know if I could manage to resolve the problem. If anyone had similar problems,let me know please

oferreira.andre · 08-13-2016, 03:01 AM

Just notice that I can't downgrade the firmware, I want to install the 1.15, but it can't replace the 1.16. Any chance that some dust in the mirror could explain that focus difference between liveview and eyeview? It doesn't explain anyway why tha focus fine ajustment it isn't working, I guess

sambista · 07-26-2020, 09:10 AM

Hello
Old thread but I have the same issue with my k-5 (about 15k shots) and 17-70/f4. Hard (almost impossible today) to obtain a focused photo with viewfinder but it works in liveview mode. AF fine adjustment seems to have no effect.
Any clue ?
Thanks

deoncam · 09-02-2020, 02:21 PM

My camera developed the same problem about 4 years ago. Viewfinder AF started to struggle, eventually got worse then gave up. It doesn’t even track anymore to try to focus while using the viewfinder. In Live View mode however, it works perfectly. I no longer use the camera. Just came here to see if a solution has been found.

**mikesbike** · 09-04-2020, 07:32 PM

Usually, a problem with back-focus or front-focus is due to a mis-match between the lens variance and the camera AF setting when manufactured. Hence Pentax came up with this control feature to enable the user to vary this relationship for an individual lens and the camera. What I am saying is, the issue would most likely be different with different lenses, if any issue at all.

So if the issue is the same with every lens, and there had been no prior issue with the same lenses, something has gone wrong within the camera. Others on this forum are more technically knowledgeable than I, but I do recall there is a separate mirror specifically for AF, which can get some dirt on it and cause problems to occur. I have never had to clean mine, but I have seen some advice for doing so with an air-blower. I do not think it wise to actually touch either of the mirrors.

The only problem I had with AF in using my then new K-5, was with one lens (though I did not try it with all my lenses), which was my FA 43mm Limited, which I was able to resolve via the focus adjustment. Later upon getting a new K-5 IIs, which incorporated a new updated AF system, I had no problem with any lens.

08-11-2016, 10:57 AM	#1
oferreira.andre New Member Join Date: Aug 2016 Posts: 4	AF problem in K-5 Hello! I bought and Pentax K-5 with a 12k shutter count. It came with the 18-55 WR, I also have the 35-135 and the 50 f1.7 I have it for few days, but I notice that the photos are a bit soft and threfocus point is on the back..I been trying to AF fine ajustment, but I can't manage to work, even in the max of the ajustment, the focus point still the same in the back. One thing I notice is that in Liveview mode the AF manage to focus correctly, the face and contrast AF detection. And also it looks like the stabilization mode only work the liveview mode too, at least I just notice it the this mode. How can I manage to resolve this problems? The firmware is the last one realesed 1.16. Thank you in advance for your help, best wishes André

08-11-2016, 12:59 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Have you used a test chart to measure the degree of AF inaccuracy? It can vary at different focal lengths, though it shouldn't be that big of a deal with the 18-55, since it has a slower aperture and thus a wider DoF than many other lenses. 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:

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08-11-2016, 01:18 PM	#3
kiwi_jono Loyal Site Supporter Join Date: Dec 2009 Location: Christchurch, New Zealand Photos: Gallery \| Albums Posts: 2,437	Excuse me for asking the obvious but are you using a fixed point (like centre point) when using phase detect AF rather than letting camera random points? Also, unlike in lens VR, you will not see the effect of the SR in the viewfinder - it only effects the actual photo.

08-11-2016, 02:26 PM	#4
bm75 Veteran Member Join Date: Aug 2014 Location: Italia Photos: Albums Posts: 354	AF fine tuning could be tricky and dangerous if you don't exactly know what to do. before doing that, try 1 - factory reset of all settings; 2 - check for firmware , eventually make an update to the latest version; 3 - make some tests in good light with the camera on a tripod (try another af lens, different from the 18-55 to see if something changes). after that, if you don't notice a different behaviour in the camera, try the AF fine tune. My experience with K5 is that you need some learning curve to be AF confident . I mostly use center point only , AFS and for critical situation in landscape I check the focusing with liveview magnification. Also remember that AF performance varies due to lens-body combo . I've experienced that AF is quite reliable in center point af in AFS but algorithms for AFC or Auto 11 points are not that reliable.

08-12-2016, 01:46 AM	#5
oferreira.andre New Member Join Date: Aug 2016 Posts: 4 Original Poster	I am using the center focus point only. Originally posted by kiwi_jono Excuse me for asking the obvious but are you using a fixed point (like centre point) when using phase detect AF rather than letting camera random points? Also, unlike in lens VR, you will not see the effect of the SR in the viewfinder - it only effects the actual photo. ---------- Post added 08-12-16 at 02:03 AM ---------- I been testing just in AFS and using just the center focus point. What I think is weird, is the focus in live view gets pretty sharp in the focus point, with the eyeview gets soft, and focus a little bit in the back. Also the fine ajustment I don't notice any difference in the focus accuracy, if is -10 or +10 is equal (off course this a example, I have been testing smaller steps). I have the last firmware, but I am thinking maybe something went wrong, and maybe I will give a try in 1.15, and check if there is any diference in the AF and in the fine ajustment. About different lens the problem is the same, the zoom 35-135 or the prime 50mm. Originally posted by bm75 AF fine tuning could be tricky and dangerous if you don't exactly know what to do. before doing that, try 1 - factory reset of all settings; 2n - check for firmware , eventually make an update to the latest version; 3 - make some tests in good light with the camera on a tripod (try another af lens, different from the 18-55 to see if something changes). after that, if you don't notice a different behaviour in the camera, try the AF fine tune. My experience with K5 is that you need some learning curve to be AF confident . I mostly use center point only , AFS and for critical situation in landscape I check the focusing with liveview magnification. Also remember that AF performance varies due to lens-body combo . I've experienced that AF is quite reliable in center point af in AFS but algorithms for AFC or Auto 11 points are not that reliable.

08-12-2016, 08:08 AM	#6
bm75 Veteran Member Join Date: Aug 2014 Location: Italia Photos: Albums Posts: 354	I'm sorry for that....it's really a strange thing that af fine adj. doesn't work. With my k5 I've never had any necessity to fine calibrate the af (also with DA17-70 that's known for being problematic) but initially I had some problems with the viewfinfìder: I didn't find the correct 0 position (uncorrected diptrics), i solved the problem with the OM-53 magnifier eyecup. Just to say that if you have problems with the viewfinder, you'll never exactly know what the af is guessing to be in focus (with some subjects in my opinion the red af squares are too big to really give the exact idea of what the af focusing in - and APSC viewfinders are small, also if pentax' are really good). As an exemple of repetitive missing focus in my experience: my k5 af doesn't like to focus small faces in typical family candids with a landscape on the back...no way to solve the problem also in AFS single central point (AFlock and recomposing - that's insidious because the focal plane can shift with wides)...no way to have eyes in focus...I know that and treat it 1- as a mine fault as a bad photographer : I have to learn composition and make better photos (typically I close the diaphragm to f/8 or more).. 2 - Perhaps af sensors have a sensitive area that's bigger than the relative small part which I want in focus. Just to say...

08-13-2016, 01:31 AM	#7
oferreira.andre New Member Join Date: Aug 2016 Posts: 4 Original Poster	Thank you for all the replies, I will try a pair of changes and do some more test,and let you know if I could manage to resolve the problem. If anyone had similar problems,let me know please

08-13-2016, 03:01 AM	#8
oferreira.andre New Member Join Date: Aug 2016 Posts: 4 Original Poster	Just notice that I can't downgrade the firmware, I want to install the 1.15, but it can't replace the 1.16. Any chance that some dust in the mirror could explain that focus difference between liveview and eyeview? It doesn't explain anyway why tha focus fine ajustment it isn't working, I guess

07-26-2020, 09:10 AM	#9
sambista New Member Join Date: Jul 2020 Posts: 1	Hello Old thread but I have the same issue with my k-5 (about 15k shots) and 17-70/f4. Hard (almost impossible today) to obtain a focused photo with viewfinder but it works in liveview mode. AF fine adjustment seems to have no effect. Any clue ? Thanks

09-02-2020, 02:21 PM	#10
deoncam New Member Join Date: Sep 2020 Posts: 3	My camera developed the same problem about 4 years ago. Viewfinder AF started to struggle, eventually got worse then gave up. It doesn’t even track anymore to try to focus while using the viewfinder. In Live View mode however, it works perfectly. I no longer use the camera. Just came here to see if a solution has been found.

09-04-2020, 07:32 PM	#11
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,564	Usually, a problem with back-focus or front-focus is due to a mis-match between the lens variance and the camera AF setting when manufactured. Hence Pentax came up with this control feature to enable the user to vary this relationship for an individual lens and the camera. What I am saying is, the issue would most likely be different with different lenses, if any issue at all. So if the issue is the same with every lens, and there had been no prior issue with the same lenses, something has gone wrong within the camera. Others on this forum are more technically knowledgeable than I, but I do recall there is a separate mirror specifically for AF, which can get some dirt on it and cause problems to occur. I have never had to clean mine, but I have seen some advice for doing so with an air-blower. I do not think it wise to actually touch either of the mirrors. The only problem I had with AF in using my then new K-5, was with one lens (though I did not try it with all my lenses), which was my FA 43mm Limited, which I was able to resolve via the focus adjustment. Later upon getting a new K-5 IIs, which incorporated a new updated AF system, I had no problem with any lens.