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Sunday, September 15, 2013

AF Fine Adjustment: "Apply All" and "Apply One" Fully Explained



Quite some time ago, I explained how to focus adjust a K-5 camera using Live View. However, there are some confusions amongst Pentax users over time for the meanings and effects of the "Apply All" and "Apply One" settings. So, I opt to explain more this time. Well, the user manual tells nothing useful about these once again, just see page 126 of the K-5 user manual! >:-(

For a camera like the K-5 and K-30/50/500 which lacks a f/2.8 sensors, this "AF Fine Adjustment" is crucial so as to compensate the spherical aberration that exists on all lenses when stopped down against wide opened, which causes the camera to mis-focus depending on the amount of differences. It is because the AF system actually measures the more central part of the lenses optically for those f/5.6 AF sensors.

So, here we go, we have four scenarios:

1. Nothing is Set:



This is essentially the same as to set in the Custom Function that the "AF Fine Adjustment" is Turned Off / Disabled.

2. "Apply All" is Set but "Apply One" Not:



So, All lenses will use the "+5" setting as shown in the above example which is obvious. Do note that a +ve setting is meant to instruct the camera to focus fronter (to compensate back focusing) and vice versa for a "-ve" value to instruct the camera to focus backwards (to compensate front focusing).

3."Apply All" is Not Set and "Apply One" is Set (for Individual Lenses):



This is also obvious, the "Apply One" setting will take effect when individual lens is mounted of which the lens identity number is detected (for a Pentax F AF lens or later). So, I now know why the official user manual just tells you "Apply All" means apply all, "Apply One" means apply one or something like that but no more! ;-p

Choose this only if your camera does not contain any AF error primitively by itself, like my own K-5 unit which is a perfect copy already! :-D

4. Both "Apply All" and "Apply One" are Set:



Well, what does it mean under this case? Is it actually +2, +5 or +7?? What do you think? :-o For what I checked, it is actually +2, that means that the "Apply One" setting overrides the "Apply All". Whilst this does make sense somehow but however, the "Apply One" is not applied on top of the "Apply All" as many Pentax users wished!

Btw, if you have a copy of your Pentax camera which needs some slight adjustment by itself for *all* lenses, i.e. sample variations with some system errors, set both and remember to individually calibrate all your lenses unless the "Apply All" already works for all your lenses, i.e. scenario #2! Frankly, if you have more prime lenses like me, calibrating each lens is inevitably unavoidable!

Last but not least, some people would be puzzled for what to do with a cheap DAL or even "DA" lenses which does not have a focusing mark (namely, the DA35/2.4, DA50/1.8 and the DA40/2.8XS lens). Well, what you need to do is to put on a sticker and make the mark yourself before doing any further calibration! See the following example. :-)



Besides, some people would still wonder, do the K-5II/s need such "AF Fine Adjustment"? My answer is Yes, if you are using really Fast Prime like the DA*55/1.4 or just an old FA50/1.4 and etc., of which spherical aberration still occurs in between the widest aperture of f/1.4 down right to the f/2.8 aperture where the AF is detected and measured. So, the above techniques do still always apply! And also don't forget that not every copy of the K-5II/s is perfectly quality controlled when it was produced from the Pentax' (and now Ricoh's) factory.

Comments (17)

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Ahhhh...so this is why my M50 1.4 focus shifts in low light? Hmmm, explains a lot. It always seemed like lenses that were faster than 2.8 focus shifted the most. Now I know why. Interesting to know that apply one overrides apply all. I always assumed that, but nice to know that is in fact true. Thanks.
1 reply · active 599 weeks ago
You're welcome. :-)
It written in manual. Use either Apply All, or Apply One (for 20 lenses individually) - no any addition of settings.
3 replies · active 599 weeks ago
Apply All and Apply One can be set at the same time, can't you see the above screen picture?
No any sense to set it together. RTFM.
I already explained above for why and when it might need to set both!
Dan Johnson's avatar

Dan Johnson · 599 weeks ago

Thanks for helping Pentaxian's who can't get Sigma's USB Dock to adjust their 35mm f/1.4, 18-35mm f1.8, or 120-300mm f/2.8 OS, (until Sigma wants Pentaxian's $60) I'll hold off buying their new lenses evan if they come out with a brighter full frame zoom or a remake of their macro (brighter with an adjustable magnification (1/4 to life-size) for portrait/limited-crop) as well as the focus limiter.
2 replies · active 599 weeks ago
Sigma's USB dock lens calibrator is actually a nonsense product. It is because they should do the quality check at the factory, but not by the users. And the most important point that focus calibration is needed to be carried out with the body as a whole, but not for the lens alone, which as I have just said, should be properly done before the lenses were shipped out of the factory!
It's not only a matter of quality check and USB Dock is far more useful than simple in-body microadjustments.
Extremely helpful post. Many thanx!
Hi, I've been using this technique for about 2 years. It has worked great for me so far. However, re-reading you original post I discovered this statement: "Do note that the camera only supports Pentax lenses with an identifiable lens ID for the Pentax F series AF lenses or later". Are you sure about it? I have two back focusing long Sigmas: 180/3.5 macro and 500/4.5. And I used to think that they are covered by K-5 AF micro adjustment. Actually the 500/4.5 is beyond +10; and I shoot it now at +10 single lens micro adjustment. Now I'm frustrated a bit. I called Pentax/Ricoh USA today and they simply said that they don't know. K-5 may or may not support the Sigmas. They do not test Pentax cameras with 3rd parties lenses.
Anyway it looks like my K-5 sensor is shifted a bit. I have the same +4 for FA300/4.5, long end of DA*60-250/4, and Sigma 180/3.5. So, what do you think, if I set AF micro adjustment for, let's say, +4 Apply All. Would it work for Sigmas too?
Thank you in advance,
SG
2 replies · active 599 weeks ago
The modern Sigma K-mount lenses should have a lens id also, but it is of course not to be recognised by the Pentax software if it is not cloned. However, the AF adjustment should work.
Thank you for the reply. I do believe that AF micro adjustment does work with Sigma lenses. However, I was devastated when I read your comment about exclusivity of AF micro adjustment for Pentax lenses only.
Thank you again,
SG
Thanks for the great job, a newbie question: what would you do on a zoom lens that has opposite sign compensation at the two ends? Case in point, a DA 17-70. Also, I have the impression some lenses actually would need more than the maximum allowed correction to reach perfect infinity focus (I also check front-back focus at infinity because that's where I see most problems, some lenses just hit the end stop and can't reach focus), is there any manipulation of the hidden menus that allow to go a bit beyond?
Thanks in advance
Maurizio
1 reply · active 543 weeks ago
I have the DA 17-70. You should calibrate focus to infinity first at 70mm. Then check at 10ft or so. It struggles most with focus at 70mm so refocus and take multiple shots to confirm. Finally I usually check how things look at minimum focus. Do note that this lens focus shifts with aperture, so focusing manually in live view wide open will give you incorrect focus when you stop down. My k5 would struggle to lock focus @ infinity in live view at 70mm due to the problems with the an short focus throw. It has some wicked field curvature at 17mm so don't expect sharp edges unless you focus carefully or stop way down. I like this lens, but its focus issues at 70mm can be annoying. Best to focus twice on a good solid edge so it can microadjust a bit. If you have lenses that need to go beyond 10 you can move the zero point in debug mode, but you have to be careful. Your mount might not have perfect distance too. Best to confirm infinity with manual lenses that have good infinity stops and work from there. If your a newbie I'd be careful what you do. Feel free to reply.
I am not a newbie in photography, but surely am in touching the innards of the camera. And I didn't know the 17-70 had these issues (curvature, focus shift with aperture) also because I use it mostly a f8 or higher to have maximum sharpness, but the focus issues of course gave awful results at 70mm.
I would like to test the move beyond 10, how is it done? What should I be attentive to? Of course this would create problems with any lenses needing -10, isn't there a way to widen teh range altogether? I understood this were possible on the K10, for instance, through debug mode.
Thanks a lot
Ian Bullivant's avatar

Ian Bullivant · 365 weeks ago

Brilliant tech advise many thanks. A grateful Pentax K7D user with a now much sharper lens :+)

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