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02-24-2012, 09:10 AM - 4 Likes   #46
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I did these tests to try to further understand the actual functioning of the AF Adjustment, and finally figured it out.

All lens swaps involved powering off the body. AF Adjustment values were checked in EXIF of the RAW pics.

Start with AF Adjustment Off, [ALL] = 0; [ONE]= unset

Power Up with 18-135 lens

Set 18-135 [ONE] to +2
Set [ALL] to +5
* take picture: AF used = +5

Swap in 70mm DA
Set [ONE] to +7
'OK' [ALL] at +5
* take picture AF used = +5

Swap in 18-135
* take picture: AF used = +5
Power Off/ON
* take picture: AF used = +5

Swap in 70mm
* take picture: AF used = +5
'OK' [ONE] at +6
* take picture: AF used = +6

Swap in 18-135
* take picture: AF used = +5

Power Up with 18-135
OK [ONE] at +2
* take picture: +2 used
Power Cycle
* take picture: +2 used

Swap in 70mm
* take picture: +6 used ([ONE] value I last set for 70mm above)

Swap in 18-135
* take picture: +2 used ([ONE] value I last OKd for this lens)

OK [ALL] at +5 with 18-135
* take picture: +5 used

Swap in 70mm
* take picture: +6 used ([ONE] value)

Swap in 18-135
* take picture: +5 used ([ALL] value last OK'd with this lens)


An [ALL] setting will over-ride a [ONE] setting for that lens IF [ALL] was OK'd last with that lens.
A [ONE] setting will be used for a specific lens IF that [ONE] setting was OK'd last with that lens.

SOO, as the manual hints, whatever value [ALL] or [ONE] was OK'd last with a specific lens will be the AF value used for that lens.

Sort of makes sense...as long as you are aware of it.

02-24-2012, 01:03 PM   #47
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QuoteOriginally posted by jmg257 Quote
I did these tests to try to further understand the actual functioning of the AF Adjustment, and finally figured it out.

....

An [ALL] setting will over-ride a [ONE] setting for that lens IF [ALL] was OK'd last with that lens.
A [ONE] setting will be used for a specific lens IF that [ONE] setting was OK'd last with that lens.

SOO, as the manual hints, whatever value [ALL] or [ONE] was OK'd last with a specific lens will be the AF value used for that lens.

Sort of makes sense...as long as you are aware of it.
Good work! My understanding from the manual was that an All setting affected all lenses.

Now from your work, it appears that All is used when there is no One setting for the installed lens. So we can have a mixture of All and One settings - sounds good! Folks who believe they have turned off Fine Adjustment by setting All=0 may not have turned it off if they have One settings - is that correct?

As to the other issue of whether to use fine Adjustment at all. I've read posts saying that BF/FF can change depending on how close the subject is. I've experienced that myself when calibrating an FA50 in close, and then finding out it was it was not focused at 40 feet. Then one gets into the whole zoom lens business where BF/FF can changed based on what FL is being used.

Perhaps, what it comes down to is if we have a specific application, e.g. stage shots at 20 feet, that a specific lens might be successfully fine tuned to that application. But in general, setting All=0 is not a bad setting for all other lenses because its a median value which ignores all the individual lens characteristics.

If we're having problems with several lenses, than perhaps its time to send the camera in for an overall calibration, e.g. Christine's situation where she's an experienced shooter, happy with the K5 at one time, but no longer, sends the camera in and its performance is restored.
02-24-2012, 03:10 PM   #48
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Hmmm...good question...it seems what will be used is very dependent on what was done last i.e was [ALL] or [ONE] OKd with that specific lens, IF [ONE] is set to some value (as opposed to "UNSET").

So it seems you are right - if I OK [ALL] to 0 with one lens installed - that lens will use AF 0. But another lens that was set/OKd with a different [ONE] value will still use that value.
02-24-2012, 11:19 PM   #49
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@jmg257

Thanks for taking the time to test this.
This is a counterintuitive implementation, wish they would rethink it or at least explain it better in the manual.

If I understand correctly, for each lens we can set 2 values, a common one - the ALL; and a value that depends on the lens - the ONE.
Then we can select one of the two values for each lens, and the camera will revert to the last set value for that specific lens.

While I'm sure there's a calibration procedure that works well with this specific implementation, I wish they would give us the procedure. Now it looks like a factory calibration tool with no instruction about how to use it.

02-25-2012, 01:02 AM   #50
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I remember reading that the ALL setting overrides the ONE setting in all cases if the camera AF adjust mode is set to ALL. The MODE is either ALL or ONE and there's no mix as far as I understand it. As to whether the camera applies AF micro-adjustments according to the chip in the lens automatically, regardless of the AF feature being ON or OFF, that is another question.
02-25-2012, 11:44 AM   #51
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Which is why I tested it. The manual memos how it works, but isn't very clear. There were also some notions that the [ALL] and [ONE] settings might be cumulative.

As noted, the [ALL] will over-ride the [ONE] if set, but only if [ALL] was set/OKd last with that lens on the camera. A lens-specific [ONE] will be used for that lens IF it was the setting OKd last with that lens installed. AF Adjustment is either OFF or ON, and ON could even be with [ALL] at 0, which 1) would override a len's [ONE] value IF [ALL]=0 was OKd last with that lens; and 2) per the manual it is very likely, if there was a lens-chip setting, an [ALL]=0 would override it too. FWIW, when I bothered looking, I haven't seen any AF setting used other then 0 or what I set in [ALL] or [ONE].

So you can mix across lenses, just depends on which one you set (OK) last with a specific lens. Seems it could get very confusing though, but once set for a lens, it shouldn't change.

Last edited by jmg257; 02-25-2012 at 12:32 PM.
02-26-2012, 01:18 AM   #52
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I wish I could remember where I read it but I'm pretty certain it was a Pentax rep who stated it:

1: The ALL overrides the ONE every time and is a global camera adjustment. It probably +/- the lens chip's settings per lens from the factory and has nothing to do with any adjustment you may have made in the ONE menu.
2: Any differing numbers you may record are probably the global being +/- to that factory setting and nothing more.
02-26-2012, 08:17 AM   #53
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Yep - appears he was wrong, re: [ALL] vs [ONE].

He could be right that an in-lens setting, if one actually exists that would be used by the AF module during calcs, would be 'invisible' to the camera settings and EXIF - and is calculated in w/o reporting. Which would make sense...like an AF Shift for a body done in service software (or via debug mode), a specific uM value used in calculations but not reported (or easily identified anway!) in EXIF.

I can't think of a way to test in-lens if/when if the values aren't reported. Anyway, while interesting to know, it doesn't seem as important as knowing which ALL or ONE value will be used at any time with a certain lens (sumed up best by 'whichever was set last...').


Last edited by jmg257; 02-26-2012 at 11:26 AM.
03-03-2012, 05:10 AM   #54
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And the camera can save up to 20 "ONE" settings for different lenses. However, it doesn't use the lens serial number but it's focal length - so if you have two 50mm lenses it can't tell them apart. At least that's my understanding from reading several reviews on the 'net. I believe if the lens can't talk to the body you can enter the focal length manually so your AF fine tuning will work.

My K-5 doesn't arrive until Weds ( ;-) , but AF fine tuning was one of the reasons I bought it over any similarly-priced DSLR - they don't have it. Of course I also chose it because of the build quality, the excellent feature set, the wonderful low noise specs, and the fact that I've had a soft spot for Pentax since the 1980s when I was shooting film.
03-31-2012, 12:15 PM   #55
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Top notch work jmg257!
04-03-2012, 01:21 AM   #56
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So in the End, ON will ignore factory calibration for Lens or Not?
04-03-2012, 05:55 AM   #57
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Hard to know what is set, or how, for factory calibration of lenses...I can't find much info on the topic. I would like to think there is some software setting in a lens chip that's been calibrated to a 'master/reference body'...but maybe they are hardware adjusted...maybe both like the bodies? Maybe it depends on the lens? (all this vs just leaving it to manufacturing build tolerances).

Anyway, when setting AF On or Off in the menu, it states "Off - fine adjustment disabled. Lenses will focus according to factory default tolerances". And On is "...Fine adjustment enabled - press right arrow to fine tune lens target focus".

Does "factory default tolerances" refer to hardware only? Does it mean to include factory calibration settings?

Hmmm...I would also like to think any setting made in the camera takes the lens' 'factory adjustment' into consideration - whatever that is, and we are just 'fine tuning' it. .

Last edited by jmg257; 04-03-2012 at 06:03 AM.
12-26-2012, 03:43 PM   #58
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Interesting thread.
Today I have done micro adjustment on all my wifes lenses, and all my own on our K-5 s
Yes the adjustment was ON

Then I read this thread and tryed with the adjustment on/off on all lenses.

ALL lenses is sharper when I turn the lens correction off.
Why on earth I dont know, but everything is much bether.

Now I will try without th SR for a few days.

Thanks to you all.

Rune
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