AF on K-3 Dazed and Confused

Driline · 05-02-2015, 02:39 PM

I've already perused many threads on AF adjustment and still my questions cannot be answered.

1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted)

2) Those with K manual lenses must set their AF adjustment to "Global" to work. If you do that, won't that also screw up the rest of your AF lenses? So if you set global to -8 for instance on a K lens, then when I switch lenses to say my DA*16-50 it will also be -8? That obviously won't work. So whats the point of using Global? Or is my assumption incorrect?

**monochrome** · 05-02-2015, 03:01 PM

Originally posted by Driline

I've already perused many threads on AF adjustment and still my questions cannot be answered.

1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted)

2) Those with K manual lenses must set their AF adjustment to "Global" to work. If you do that, won't that also screw up the rest of your AF lenses? So if you set global to -8 for instance on a K lens, then when I switch lenses to say my DA*16-50 it will also be -8? That obviously won't work. So whats the point of using Global? Or is my assumption incorrect?

I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens. What you see in the passive viewfinder is what you see. Same for what the focus peaking sees on the rear LCD.

Na Horuk · 05-02-2015, 03:26 PM

Originally posted by Driline

1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted)

I am not sure about the K-3, but global focus adjustments affect manual lenses as well. Don't think a "per lens" adjustment is possible with manual lenses. The thing is that the camera cannot identify manual lenses (and even some third party AF lenses), because they provide zero information. So the camera cannot make a lens AF adjustment profile if it doesn't know what lens, if any at all, is mounted.

You can try doing a global + and then - for the specific AF lenses to counter it. Another thing you can try is simply calibrating the manual lens. I mean physically adjusting its focus until it fits your camera better, so that no adjustment is needed.

And btw, live view is unaffected by focus adjustment, because it uses contrast detect. It should be fairly accurate, especially for primes

stevebrot · 05-02-2015, 05:30 PM

Originally posted by monochrome

I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens.

I can understand the desire, but am uncertain of the outcome. At best, you can only apply a global correction (see OP and Na Horuk above) and that is of limited usefulness. As monochrome notes, the best options are the optical viewfinder and live view. The optical viewfinder with the stock screen is problematic (poor precision), but many users report improved results with a viewfinder magnifier. I opted for an aftermarket screen (split image) dialed in against magnified live view.

Steve

**Rondec** · 05-02-2015, 06:37 PM

The issue is that the camera doesn't really know what lens is on the camera for pre-A lenses, right? So you can't really set a specific auto focus adjustment for those lenses.

sterretje · 05-02-2015, 11:29 PM

Originally posted by monochrome

I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens.

One reason can be to adjust for CIF.

JinDesu · 05-02-2015, 11:35 PM

Originally posted by Rondec

The issue is that the camera doesn't really know what lens is on the camera for pre-A lenses, right? So you can't really set a specific auto focus adjustment for those lenses.

The adjustment process is based on manually focusing the lens and checking in which direction you should be adjusting - so it's technically lens model independent. And it's as another user said, it's good to make sure that CIF working correctly.

Driline · 05-03-2015, 07:11 AM

Originally posted by sterretje

One reason can be to adjust for CIF.

Exactly. So one question remains. If I change this globally because that's my only choice with a manual lens, will the change persist and scew up my other lenses? If so is there a solution for this?

**monochrome** · 05-03-2015, 07:28 AM

Originally posted by Driline

Exactly. So one question remains. If I change this globally because that's my only choice with a manual lens, will the change persist and scew up my other lenses? If so is there a solution for this?

OK - I get it now. I've never had a need to use CIF - though I often use AF-C with backbutton focus and auto-focus lenses.

It seems to me global correction for manual lenses will certainly affect all manual lenses, and probably all AF lenses as well. If that is correct you would then need to individually correct each chipped lens relative to the new global correction.

sterretje · 05-03-2015, 07:28 AM

On older bodies it was always said that global setting does not influence the individual adjustment. But if I'm not mistaken, there are recent statements that they are cumulative on newer bodies. Test and you know

aleonx3 · 05-03-2015, 07:58 AM

I use the global adjustment for all my manual focus lenses including k or m42 mount. I used individual adjustment for AF lenses, each one is slightly different. I can use the green hexagon via the viewfinder for all manual focus lenses including CIF. The only restriction is that I can only use the center-focus point; which is fine since I can crop with the k-3 images. The global and individual adjustments could be cumulative or could be independent of each other. I have not been able to identify one way or the other.

Driline · 05-03-2015, 10:10 AM

Originally posted by monochrome

It seems to me global correction for manual lenses will certainly affect all manual lenses, and probably all AF lenses as well

If that's true, then the only way I see around this is to simply turn AF on line 26 "ON" for my single manual lens and set it to -8, and then when finished simply turn it "OFF" so i don't have to go in and individually set 300 or more AF lenses to compensate for one silly manual focus lens

Driline · 05-03-2015, 01:52 PM

Here's a pic wide open at 2.5 with AF set to OFF. I think I just need practice nailing the focus.

Na Horuk · 05-03-2015, 04:31 PM

Originally posted by Driline

Here's a pic wide open at 2.5 with AF set to OFF. I think I just need practice nailing the focus.

Yes, practicing MF can do wonders! Other helpful tools are viewfinder loupe (Pentax, Seagull, or other makers) and focusing screens (Focusing screen com, Katzeye, JinFinance, etc.).
CiF is helpful, too, but it takes some getting used to. For example, it will be important whether you focus from infinity to near, or from near to infinity. How quickly you twist the ring can also affect when the camera finds a lock. And the lens itself can have an effect, for example using ultra wide lenses or really slow aperture lenses might not work very well. I think some other special lenses with really low contrast also had problems triggering CiF. Some people like to use CiF in combination with bust mode and just take a bunch of photos, knowing that a couple will be out of focus, but one should be right. Then delete all but the best.

05-02-2015, 02:39 PM	#1
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,697	AF on K-3 Dazed and Confused I've already perused many threads on AF adjustment and still my questions cannot be answered. 1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted) 2) Those with K manual lenses must set their AF adjustment to "Global" to work. If you do that, won't that also screw up the rest of your AF lenses? So if you set global to -8 for instance on a K lens, then when I switch lenses to say my DA*16-50 it will also be -8? That obviously won't work. So whats the point of using Global? Or is my assumption incorrect?

05-03-2015, 07:58 AM	#11
aleonx3 Veteran Member Join Date: Jul 2007 Location: Brampton, Ontario Photos: Gallery \| Albums Posts: 3,996	I use the global adjustment for all my manual focus lenses including k or m42 mount. I used individual adjustment for AF lenses, each one is slightly different. I can use the green hexagon via the viewfinder for all manual focus lenses including CIF. The only restriction is that I can only use the center-focus point; which is fine since I can crop with the k-3 images. The global and individual adjustments could be cumulative or could be independent of each other. I have not been able to identify one way or the other. Last edited by aleonx3; 05-03-2015 at 08:25 AM.

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05-02-2015, 03:01 PM	#2
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	Originally posted by Driline I've already perused many threads on AF adjustment and still my questions cannot be answered. 1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted) 2) Those with K manual lenses must set their AF adjustment to "Global" to work. If you do that, won't that also screw up the rest of your AF lenses? So if you set global to -8 for instance on a K lens, then when I switch lenses to say my DA*16-50 it will also be -8? That obviously won't work. So whats the point of using Global? Or is my assumption incorrect? I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens. What you see in the passive viewfinder is what you see. Same for what the focus peaking sees on the rear LCD.

05-02-2015, 03:26 PM	#3
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Originally posted by Driline 1) is the AF Fine Adjustment on Line 26 for auto focus lenses only? No manual lenses correct? (wondering if setting it for manual lenses if the green in focus led can be adjusted) I am not sure about the K-3, but global focus adjustments affect manual lenses as well. Don't think a "per lens" adjustment is possible with manual lenses. The thing is that the camera cannot identify manual lenses (and even some third party AF lenses), because they provide zero information. So the camera cannot make a lens AF adjustment profile if it doesn't know what lens, if any at all, is mounted. You can try doing a global + and then - for the specific AF lenses to counter it. Another thing you can try is simply calibrating the manual lens. I mean physically adjusting its focus until it fits your camera better, so that no adjustment is needed. And btw, live view is unaffected by focus adjustment, because it uses contrast detect. It should be fairly accurate, especially for primes

05-02-2015, 05:30 PM	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by monochrome I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens. I can understand the desire, but am uncertain of the outcome. At best, you can only apply a global correction (see OP and Na Horuk above) and that is of limited usefulness. As monochrome notes, the best options are the optical viewfinder and live view. The optical viewfinder with the stock screen is problematic (poor precision), but many users report improved results with a viewfinder magnifier. I opted for an aftermarket screen (split image) dialed in against magnified live view. Steve

05-02-2015, 06:37 PM	#5
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,653	The issue is that the camera doesn't really know what lens is on the camera for pre-A lenses, right? So you can't really set a specific auto focus adjustment for those lenses.

05-02-2015, 11:29 PM	#6
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	Originally posted by monochrome I'm not quite sure I understand why you want to tune the auto-focus algo for a manual focus lens. One reason can be to adjust for CIF.

05-02-2015, 11:35 PM	#7
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Originally posted by Rondec The issue is that the camera doesn't really know what lens is on the camera for pre-A lenses, right? So you can't really set a specific auto focus adjustment for those lenses. The adjustment process is based on manually focusing the lens and checking in which direction you should be adjusting - so it's technically lens model independent. And it's as another user said, it's good to make sure that CIF working correctly.

05-03-2015, 07:11 AM	#8
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,697 Original Poster	Originally posted by sterretje One reason can be to adjust for CIF. Exactly. So one question remains. If I change this globally because that's my only choice with a manual lens, will the change persist and scew up my other lenses? If so is there a solution for this?

05-03-2015, 07:28 AM	#9
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	Originally posted by Driline Exactly. So one question remains. If I change this globally because that's my only choice with a manual lens, will the change persist and scew up my other lenses? If so is there a solution for this? OK - I get it now. I've never had a need to use CIF - though I often use AF-C with backbutton focus and auto-focus lenses. It seems to me global correction for manual lenses will certainly affect all manual lenses, and probably all AF lenses as well. If that is correct you would then need to individually correct each chipped lens relative to the new global correction.

05-03-2015, 07:28 AM	#10
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	On older bodies it was always said that global setting does not influence the individual adjustment. But if I'm not mistaken, there are recent statements that they are cumulative on newer bodies. Test and you know

05-03-2015, 10:10 AM	#12
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,697 Original Poster	Originally posted by monochrome It seems to me global correction for manual lenses will certainly affect all manual lenses, and probably all AF lenses as well If that's true, then the only way I see around this is to simply turn AF on line 26 "ON" for my single manual lens and set it to -8, and then when finished simply turn it "OFF" so i don't have to go in and individually set 300 or more AF lenses to compensate for one silly manual focus lens

05-03-2015, 01:52 PM	#13
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,697 Original Poster	Here's a pic wide open at 2.5 with AF set to OFF. I think I just need practice nailing the focus.

05-03-2015, 04:31 PM	#14
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Originally posted by Driline Here's a pic wide open at 2.5 with AF set to OFF. I think I just need practice nailing the focus. Yes, practicing MF can do wonders! Other helpful tools are viewfinder loupe (Pentax, Seagull, or other makers) and focusing screens (Focusing screen com, Katzeye, JinFinance, etc.). CiF is helpful, too, but it takes some getting used to. For example, it will be important whether you focus from infinity to near, or from near to infinity. How quickly you twist the ring can also affect when the camera finds a lock. And the lens itself can have an effect, for example using ultra wide lenses or really slow aperture lenses might not work very well. I think some other special lenses with really low contrast also had problems triggering CiF. Some people like to use CiF in combination with bust mode and just take a bunch of photos, knowing that a couple will be out of focus, but one should be right. Then delete all but the best.