AF Micro-Adjustment Confusion

RustyToyotaVT · 09-11-2015, 07:05 AM

Maybe someone can shed some light on this for me. On my K3, I need varying levels of adjustment for all of my lenses. I use a SpyderLensCal to calibrate. +5 on my 18-135, +2 on my 35 Limited, 0 on my 55-300, -2 on my 50 1.4, and +10 (!!) on my 16-50. My K7 requires very similar levels of adjustment. Until recently, I just accepted this as sample variation with the lens manufacturing process.

My dilemma is that I recently discovered that each of these lenses miraculously works perfectly without ANY AF adjustment on my mother's K50. How is this even possible? Does this indicate a problem with my K3 and K7? Or with her K50? Is it voodoo?

I just don't get it. I understand sample variation between bodies, but I would expect a similar spread between the lenses regardless of the body. i.e. how can my 55-300 and 16-50 have an 8-10 point spread between each other on my other bodies but neither requires any adjustment on the K50?

Any insight you can share would be tremendously helpful.

Thanks!

**jatrax** · 09-11-2015, 08:00 AM

Not sure I can explain why but it is not unusual. My k-5 required various adjustments on almost all lenses. My k-3 required no adjustments on any lens.

RustyToyotaVT · 09-11-2015, 08:17 AM

Originally posted by jatrax

Not sure I can explain why but it is not unusual. My k-5 required various adjustments on almost all lenses. My k-3 required no adjustments on any lens.

Thanks jatrax, at least I know I'm not the only one who sees this type of behavior.

FWIW I must say, I've really liked using this K-50. I'm a bit of a snob and have always owned "prosumer" DSLRs, but now I wonder if I haven't wasted a bit of $$$ over the years

Fauxton · 09-11-2015, 11:20 AM - **1 Like**

Originally posted by sweendiggs

Maybe someone can shed some light on this for me. On my K3, I need varying levels of adjustment for all of my lenses. I use a SpyderLensCal to calibrate. +5 on my 18-135, +2 on my 35 Limited, 0 on my 55-300, -2 on my 50 1.4, and +10 (!!) on my 16-50. My K7 requires very similar levels of adjustment. Until recently, I just accepted this as sample variation with the lens manufacturing process.

My dilemma is that I recently discovered that each of these lenses miraculously works perfectly without ANY AF adjustment on my mother's K50. How is this even possible? Does this indicate a problem with my K3 and K7? Or with her K50? Is it voodoo?

I just don't get it. I understand sample variation between bodies, but I would expect a similar spread between the lenses regardless of the body. i.e. how can my 55-300 and 16-50 have an 8-10 point spread between each other on my other bodies but neither requires any adjustment on the K50?

Any insight you can share would be tremendously helpful.

Thanks!

Fairly simple answer - one of the major variables is the AF subsystem itself. The AF sensor, logic and design is different between those cameras. The AF performance, for example the sensor and its loop parameters can also interact with the lens characteristics (poles and zeros in the control equations/solution) and cause differences in performance between lenses on the same camera. This is also why, in part ( there are other reasons) that zooms lenses focus differently at either ends of the zoom range. Also the lower resolution is a bit more forgiving. As the megapixels climb the mis focusing can become a bit more evident.

RustyToyotaVT · 09-11-2015, 04:42 PM

Originally posted by Fauxton

Fairly simple answer - one of the major variables is the AF subsystem itself. The AF sensor, logic and design is different between those cameras. The AF performance, for example the sensor and its loop parameters can also interact with the lens characteristics (poles and zeros in the control equations/solution) and cause differences in performance between lenses on the same camera. This is also why, in part ( there are other reasons) that zooms lenses focus differently at either ends of the zoom range. Also the lower resolution is a bit more forgiving. As the megapixels climb the mis focusing can become a bit more evident.

Good info, thank you!

09-11-2015, 07:05 AM	#1
RustyToyotaVT Senior Member Join Date: Feb 2011 Location: UK Posts: 103	AF Micro-Adjustment Confusion Maybe someone can shed some light on this for me. On my K3, I need varying levels of adjustment for all of my lenses. I use a SpyderLensCal to calibrate. +5 on my 18-135, +2 on my 35 Limited, 0 on my 55-300, -2 on my 50 1.4, and +10 (!!) on my 16-50. My K7 requires very similar levels of adjustment. Until recently, I just accepted this as sample variation with the lens manufacturing process. My dilemma is that I recently discovered that each of these lenses miraculously works perfectly without ANY AF adjustment on my mother's K50. How is this even possible? Does this indicate a problem with my K3 and K7? Or with her K50? Is it voodoo? I just don't get it. I understand sample variation between bodies, but I would expect a similar spread between the lenses regardless of the body. i.e. how can my 55-300 and 16-50 have an 8-10 point spread between each other on my other bodies but neither requires any adjustment on the K50? Any insight you can share would be tremendously helpful. Thanks!

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09-11-2015, 08:00 AM	#2
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Not sure I can explain why but it is not unusual. My k-5 required various adjustments on almost all lenses. My k-3 required no adjustments on any lens.

09-11-2015, 08:17 AM	#3
RustyToyotaVT Senior Member Join Date: Feb 2011 Location: UK Posts: 103 Original Poster	Originally posted by jatrax Not sure I can explain why but it is not unusual. My k-5 required various adjustments on almost all lenses. My k-3 required no adjustments on any lens. Thanks jatrax, at least I know I'm not the only one who sees this type of behavior. FWIW I must say, I've really liked using this K-50. I'm a bit of a snob and have always owned "prosumer" DSLRs, but now I wonder if I haven't wasted a bit of $$$ over the years

09-11-2015, 11:20 AM - 1 Like	#4
Fauxton Senior Member Join Date: Oct 2011 Posts: 100	Originally posted by sweendiggs Maybe someone can shed some light on this for me. On my K3, I need varying levels of adjustment for all of my lenses. I use a SpyderLensCal to calibrate. +5 on my 18-135, +2 on my 35 Limited, 0 on my 55-300, -2 on my 50 1.4, and +10 (!!) on my 16-50. My K7 requires very similar levels of adjustment. Until recently, I just accepted this as sample variation with the lens manufacturing process. My dilemma is that I recently discovered that each of these lenses miraculously works perfectly without ANY AF adjustment on my mother's K50. How is this even possible? Does this indicate a problem with my K3 and K7? Or with her K50? Is it voodoo? I just don't get it. I understand sample variation between bodies, but I would expect a similar spread between the lenses regardless of the body. i.e. how can my 55-300 and 16-50 have an 8-10 point spread between each other on my other bodies but neither requires any adjustment on the K50? Any insight you can share would be tremendously helpful. Thanks! Fairly simple answer - one of the major variables is the AF subsystem itself. The AF sensor, logic and design is different between those cameras. The AF performance, for example the sensor and its loop parameters can also interact with the lens characteristics (poles and zeros in the control equations/solution) and cause differences in performance between lenses on the same camera. This is also why, in part ( there are other reasons) that zooms lenses focus differently at either ends of the zoom range. Also the lower resolution is a bit more forgiving. As the megapixels climb the mis focusing can become a bit more evident.

09-11-2015, 04:42 PM	#5
RustyToyotaVT Senior Member Join Date: Feb 2011 Location: UK Posts: 103 Original Poster	Originally posted by Fauxton Fairly simple answer - one of the major variables is the AF subsystem itself. The AF sensor, logic and design is different between those cameras. The AF performance, for example the sensor and its loop parameters can also interact with the lens characteristics (poles and zeros in the control equations/solution) and cause differences in performance between lenses on the same camera. This is also why, in part ( there are other reasons) that zooms lenses focus differently at either ends of the zoom range. Also the lower resolution is a bit more forgiving. As the megapixels climb the mis focusing can become a bit more evident. Good info, thank you!