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03-25-2013, 08:47 AM   #16
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QuoteOriginally posted by ve2vfd Quote
Thanks for the heads up on that software Stormtech! I was already using their lens-align scale and had some pretty decent results, but also found I had to readjust my K5d periodically as my focus point seems to drift. This will take a lot of guesswork out of the adjustments.

Pat
No problem Pat. Actually Focus Tune is from the same founder of LensAlign - he does say that using LensAlign along with Focus Tune will give you the most accurate results. The software was made to work with LensAlign in the beginning but has also provided the ability to use it a printed target.

Although not the greatest news, it makes me feel a little better that I am not the only one experiencing this AF focus drift. This is one reason that made me buy myself another Fuji x100 - fixed lens will eliminate this problem!

I plan to do a little review of Focus Tune once the v2.0 public version is released.

03-26-2013, 06:54 AM   #17
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Stan,
This is my current method to determine AF-Fine Adjust values:

My approach is a more practical than scientific one.
Starting point is Live View (LV using contrast detection on sensor = CD-AF) being more accurate than Phase Detect AF (PD-AF or AF for short). Using manual focus in LV (LVm) with up to 10 times magnification may be even more accurate than auto focus in LV (LVa). For simplicity, I use LVa for this description.
procedure A:
Auto focus in LV (LVa), turn off LV and observe the lens barrel when auto focussing (PD-AF).
The barrel may not move, turn towards 0 or turn towards infinity (v, ->0, ->oo)
v: the AF-FA value seems to be ok (at least close to best)
->0: PD-AF does FF i.e. move the AF-FA value to negative direction (f.ex. +5 ->+1 or +2->-4 or -1->-7)
->oo:PD-AF does BF i.e. move AF-FA value to positive direction (f.ex. -2->+3)
Repeat procedure A until the lens barrel does't move anymore.

In procedure A you will find that there may be several AF-FA values without barrel movement.
Therefore we will try to find the AF-FA limits where the barrel starts moving towards 0 (V->0) and towards infinity (V->oo). Usually we'll get a range V->oo,.....,V->0 in the AF-FA scale from -10 to +10, but sometimes V->oo or V->0 may be out of this range (and can't be determined).

procedure B:
B1) Auto focus in LV (LVa), turn off LV and observe the lens barrel when auto focussing (PD-AF).
R1) The barrel may not move, turn towards 0 or turn towards infinity (v, ->0, ->oo)
Repeat B1 with a different AF-FA value until the barrel does not move.

B2) Lower the AF-FA value and repeat B1 until the barrel starts to move towards infinity (V->oo)
B3) Increase the AF-FA value and repeat B1 until the barrel starts to move towards 0 (V->0)

B4) Pick an AF-FA value in the middle between V->oo and V->0 (if you prefer slight FF, take the one to the left of the middle value).

For a zoom lens you should do procedure B at least for the wide end and the long end of the zoom and then pick an AF-FA value which is approximately in the middle of both V->oo,....,V->0 ranges. In bad situations, there may not be a common AF-FA value at all in both ranges.

You can find a video for a similar procedure here:
'Dot-Tune'

I've tried 'Dot-Tune' on my K-5 but since focus is set only once to determine the AF-FA range, it seems to depend a lot on the chosen focus setting. Also all mechanical variances are excluded since AF is turned off for the lens and only the AF indicator is used.

In procedure B above you should execute B1) several times for each AF-FA value to get good statistics with all AF elements included. (LVa does refocus each time!).

Procedure A and B can be executed without taking any picture (but you can of course).
Test setup is very similar to the one in the video. Additionally I use the following settings on my K-5::

2-sec timer (turns shake reduction off)
Enable AF on AF Button and disable AF on Shutter Button Half Press (Exposure Menu 5 'Button Customization')
Menu C1/4 'Meter Operating Time' = 3sec (minimum)
AF Center Point only
Lens aperture wide open (this is usually the case for auto focussing, but aperture may be closed for LV if target is very bright)
distance from cam to target should be about 50 times the focal length of the lens (or at least 25 times)

If the AF-FA ranges are often outside the -10,...,+10 scale (at one end), you should use Debug to control (and change) the AF -Correction value.

Thanks
03-26-2013, 07:25 AM   #18
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Before using Focus Tune, I did use the Dot Tune method. Actually the results were fairly similar so I feel the Dot Tune method is a good one.

But, the reason I like the Focus Tune method more is that with each image taken, you are making the AF work in phase detection mode. I had an idea that my AF was drifting, so forcing the AF to work in each of the 44 images would help prove that.

The other reason - when using the Dot Tune method, I had one lens where one end of my results was beyond +10 (I had a range of +2 at the bottom but at +10 I was still getting focus confirmation). That is when I decided to try Focus Tune to hopefully get more detailed results. Also with Focus Tune, you can check the focus consistency where you take a set of images at one certain AF adjustment value and it will show the constancy on the graph - again because you are de-focusing between each shot and making the AF work each time.

Here is the result of a focus consistency test:

Last edited by photolady95; 04-17-2016 at 02:53 AM.
04-23-2013, 09:47 PM   #19
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I have just recently in the last few weeks noticed a focusing problem with my k-5 IIs with my Tamron 10-24mm lens. The IIs focuses fine with my other lenses but still better in live view. I use the 10-24mm lens for real estate photography so it is very important that the lens is right on. Now on every shot I have to use live view to focus, then turn auto off to manual focus and then take my shots. Every time the live view is better than the through the prism focus. I have to figure out how to adjust it but I don't want to mess up the live view focus. I have tried using different settings and it doesn't matter what setup I use, it is not focusing correctly. I have a K-r and I did not have this same problem. Any suggestions and do you know if I mess with the focus will it also change the live view focus?

Thanks,
Racerdew

04-23-2013, 11:13 PM   #20
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Well I am following up on my post. I don't want to stir up any panic with the k-5 IIs users. I watched the above video and one other. I read my manual and played with the AF Fine tune adjustment and found the default setting to be best. I had the lens at 24mm and just about 4ft away from my subject. It came out right on every time through different settings. That test is not how I use the lens. I am usually at about 12mm shooting houses and backyards. The live view is much better for consistency. I am not sure why I don't get consistent sharp images when I am shooting in the normal through the view finder. The lens is so broad that it seems to have such a general focus and everything is slightly off. I am using a tripod for all of my shots. So I don't know why it is not as good at wide angle shots all the time. The live view focus is always right on and the other some times is off. I have tried the different settings and I don't feel like I have an advantage with any of them. Sometimes the auto 11 can pick something slightly different than what I wanted. The spot is not always the best when you are shooting a large room. However the big box of the live view is always right on.

My other lenses seem to focus great with the IIs. The 10-24mm is so wide, it might be picking up on things I just am not aware of. But the camera really wants some contrast to find it's focuse. An empty room even lit pretty good can be a problem. I think it might be many factors and not the camera body with this lens.

Racerdew
04-24-2013, 04:50 AM   #21
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QuoteOriginally posted by Racerdew Quote

Racerdew
From what you explain it sounds more like the lens having focus issues - not your camera. If you do adjust the AF fine adjustment, it will in no way affect your live view focus. The AF fine adjustment only affects the phase detect focusing which is what you are using when looking through the viewfinder.

I would suggest you test your 10-24 lens for focus adjustment. It's kind of hard sometimes with a zoom lens, but since you use it primarily at the wide end, I would do the test and adjustment at the wide end for the lens and see how it works then. You won't "break" anything by adjusting the AF adjustment - it is easy enough to hit the "reset" and put everything back to the factory default setting.
04-24-2013, 08:24 AM   #22
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I don't have K-5xxx however, when I tuned focus on my K-x I noticed that Pentax lenses work great, while Tamron 17-50 accuracy vary across multiple shots on the same shooting setup (BF/Center/FF) .

I remember reading somewhere that it is known issue with Tamron lenses.
04-24-2013, 10:27 PM   #23
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Thanks IDude for the info. Sometimes my 10-24 can be just awesome and other times I am wondering what in the world it is focusing on? Last night I played with the find adjustment and the lens worked great. I was inside using the house lights so I was fully zoomed at 24mm. It was right on every time I tested it. I moved the adjustment but the factory settings at "0" worked best. So I am gong to continue to watch it and see what makes it mis-focus. I know a plan, background with little detail makes it tough for the lens focus clearly.

Thanks,
Racerdew

06-02-2013, 09:42 PM   #24
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Follow up to my focusing problem.
I sent my Tamron 10-24mm in on warranty and it did have a problem with the focus and the aperture. They fixed it under warranty and now it works like it should. I was going crazy thinking it was me, the camera or who knows what. It was the lens and now it is as good as new or maybe better. There is nothing wrong with my K-5 IIs. Tamron did a nice job of correcting the lens and returned it pretty quickly.
08-17-2013, 09:03 AM   #25
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QuoteOriginally posted by stormtech Quote
I've read just about every thread about the new AF system I could find for the K-5IIs. My questions comes to those of you who have gone from the K-5 to the K-5IIs, and who may have had the same problem I've been experiencing with my K-5.

The short version - AF consistency is not so great with my K-5. I guess a proper term might me AF float?
Hi Stormtech
I see you got the IIs in the end. Has it solved your AF float problem?

I'm thinking of replacing my K-5 because of its inconsistent PDAF. Contrast detect AF is always spot on if the light is good enough. Within 7 or so metres most of my fast lenses need about a -1 to -6 adjustment wide open to match CDAF. At infinity the adjustment changes to -9. It drives me crazy.
08-17-2013, 03:07 PM   #26
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QuoteOriginally posted by Gray Quote
Hi Stormtech
I see you got the IIs in the end. Has it solved your AF float problem?

I'm thinking of replacing my K-5 because of its inconsistent PDAF. Contrast detect AF is always spot on if the light is good enough. Within 7 or so metres most of my fast lenses need about a -1 to -6 adjustment wide open to match CDAF. At infinity the adjustment changes to -9. It drives me crazy.
Yes it definitely did - and I am so happy for it! All of my lenses are super sharp without any AF adjustment. Seems weird actually since most of my lenses needed adjustment on my K-5 in the plus and minus range.

After shooting with my new K-5IIs for a couple months, even though all my images looked great even at 100%, I ran them all through Focus Tune a couple weeks ago just for the fun of it. Only one lens, my FA* 300 4.5 needed a +2 adjustment to make it even ohhhh that much sharper.

The short answer is yes!
08-17-2013, 06:37 PM   #27
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QuoteOriginally posted by stormtech Quote
The short answer is yes!
Thanks!
08-18-2013, 04:04 AM   #28
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This is good to know, but I do have a question. If I understand correctly, FocusTune measures the sharpness of the images. The AF adjustment for the sharpest image is then considered the "correct" AF adjustment. However, I often hear people saying they want 1/3 of the in-focus area in front of where they focused, and 2/3 behind where they focused. E.g. if you take a portrait photo and focus on the eyes, you want both the nose and most of the head to be sharp as well, stopping down as needed. But it seems to me that this is not the result you would get with this method. Or is it?
08-18-2013, 04:48 AM   #29
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It shows you which was the sharpest - yeah, sure. While that's certainly interesting bit of information, it's not what decides the 'best' AF adjustment for the camera, nor does the focus tune suggest that. It still takes the averages of the shots, and the best average is the correct adjustment, as it should be. Focus inconsistency may produce the actually sharpest image on another adjustment. But there's a fix for that: don't cut corners, do the test the even harder way.

A major problem I see overlooked by the focustune app is sample size. I have this app, and I did the adjust thing with steps of 5 at first and then 1, and shot 3-6 images at each adjustment as the app suggested, and I kept getting inconsistent results. Doing it again yielded different results.

So I thought I ain't got time for this and took 10-11 pics per AF adjusmemt, 210 images total, per lens, on the most used distance and focal length. Then I dropped the odd results which stood out from the pack. Only that gave the result the program should give.

My K-5 is now debug adjusted to -4, and all lenses are +-0. Before this they were assorted number of minus adjusted each, but the large sample test showed they all hovered around -4.
09-14-2013, 02:44 AM   #30
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QuoteOriginally posted by stormtech Quote
I guess I am the only one who has this problem with their K-5. For me, this is the second one that did the same thing.

After digging around a lot more on this subject, it seems I see a lot of people have needed to do lens adjustments with their K-5's. What really made this stick out for me is reading a thread about the K-5iis where a few folks said they had to do no AF adjustments at all with their new iis's but had to do quite a few adjustments with their K-5's. This tells me that this might be a regular problem with the K-5 and most people don't even realize it.

My second K-5 is on its way back from CRIS with the same work done as my first one - camera was back focusing - adjusted to optimal resolution. I also wonder if they physically adjust the AF sensor of do it via software like using debug mode. Also makes me wonder if or when the AF will "un-adjust" itself again.

But, since there were no replies here about any similar issues, I guess it's just me having 2 K-5's in a row like this.
Similar problems here with K5, tried all adjustments, adjustments changed with time,AF adjustment, shimmed the focussing screen. I just don't want to spend another $1200 to fix a "simple" focus problem due to crappy design of the K5. I am currently waiting for a K5II replacement and a drop in price.

I really like the apporach of Olympus where focussing is performed on the imaging sensor. Olympus even offers more hight quality fixed focal length lenses with decent apertures and quality. I will probably sell some Pentax gear quite soon and move slowly over to an OM-D
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