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09-10-2011, 10:52 AM   #1
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AF Adjustment STILL not working for me..

So I have a K7, and have posted about this before. When attempting to change my AF, I do all the settings, and it seems nothing changes.
These are a few photos taken at -5 -3 0 +3 +5, unless im missing something, I see NO difference. All were taken exactly the same. and when I went back to change the AF settings, it was as the last setting, (IE, when I changed from say 0 to +3, it showed the +3 when changing to +5, so i know it accepted the change)
All on tripod, SR off, 2 second delay, no movement etc. just change the AF adjust, next photo, AF adjust, next photo, etc.

Here is enlarged crops of the photos, so what am i doing wrong??
Tamron 17-50 2.8
K7

PS, the focus is at the intersection of the two darkest perpendicular lines.

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Last edited by SlickYamaha; 09-10-2011 at 11:43 AM.
09-10-2011, 10:57 AM   #2
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Because doing focus adjustment at macro range will never work.
09-10-2011, 11:42 AM   #3
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QuoteOriginally posted by wlachan Quote
Because doing focus adjustment at macro range will never work.
Its not the macro range, This was cropped, The lens is about 3 feet from table.
Here is the original.
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09-10-2011, 11:55 AM   #4
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You should not be aiming at the intersection of the lines. the focus point should be the middle of the horizontal line. Aiming at the intersection gives the camera to much leeway in choosing the focus point. Remember, the focus indicator in the viewfinder is approximate. Aiming at the center of the horizontal line insures that the focus is truly on the horizontal line.

09-10-2011, 12:55 PM   #5
rgk
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My K5 setup is below. I pushed things together for a better pic. I aim at the center of the pattern. Wide open, spot focus, SR off, 2sec timer, good light.

rgk

09-10-2011, 01:54 PM   #6
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QuoteOriginally posted by rgk Quote
My K5 setup is below. I pushed things together for a better pic. I aim at the center of the pattern. Wide open, spot focus, SR off, 2sec timer, good light.

rgk
How can you tell if your FF or BF?
09-10-2011, 03:27 PM   #7
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I'd go 10 0 -10 just make sure it's even working at all. Also, Aren't AF adjustments supposed to be done outdoors in daylight?
09-10-2011, 05:55 PM   #8
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QuoteOriginally posted by SlickYamaha Quote
How can you tell if your FF or BF?
The Bourque pattern I use has graduated lines and text similar to your pattern. General process is the same. I went with a test jig to make sure everything was perfectly square, but I'm sure simpler methods also work. I agree with the suggestion to try extreme steps to see of you can tell a difference. Does the K7 have the option for lens-specific adjustments or only a global common adjustment?

rgk

09-10-2011, 07:08 PM   #9
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It does lens specific and global, I'm using the lens specific method
09-10-2011, 07:38 PM   #10
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I'm sharing your frustration. I have never been happy with angled targets for two reasons:
1) you focus on a point but read the result elsewhere (usually on the right)
2) if you're not close enough the focus point (badly named, it's actually a big cross covering about the size of center circle in the VF) could lock on anything beside the target. And so you get inconsistent results.

What works for me is to use a flat target and compare the sharpness at different AF settings. Usually the settings are VERY subtle and it's really difficult to tell the difference between one increment (0 and +1 for example). I mostly use -10, -5, 0, +5 and +10.

The other thing is that some lenses are simply inconsistent. I'm testing a Sigma 30mm f/1.4 and it's not always focusing to the same point. So it becomes difficult to really have perfect accuracy.

CD-AF is usually good but not perfect. Sometimes, surprisingly, PD-AF is actually more accurate.

There's also commercial tools like "Lens Align" but it still suffers from my number 1 defect.
09-11-2011, 06:40 AM   #11
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You may want to consult these AF adjustments hints I compiled.

As others have written, it is important to have an unambiguous focus target. If you point the camera a bit above and below the target, it should not be able to focus. If it locks focus nevertheless, the AF area catches some of the measurement print to the left and right.

Remember that the AF "points" are not points but areas. You'll have to move the camera up/down quite a bit to make the centre AF area not "see" the target anymore. However, once you reach a certain angle (and you are not catching yet any of the other print over / under the target bar on the test chart) the camera shouldn't be able to lock focus anymore as the AF area only sees white paper. If you have managed to find a position / arrangement where you can achieve this inability to lock focus then point the centre AF point back to the focus target. The camera will then be able to lock focus and you'll be sure that it used the correct target to obtain focus.

BTW, I see slight differences in where the focus is in your sample images. In the last shot the target is much more in focus then in the one but last shot.

I agree with ManuH about the problem regarding the different position of the focus vs read-out area (that even the Lens Align tool has), but that method should get you pretty close.

The most precise method is AF adjustment bracketing. Note, however, that you should do multiple shots (each time putting the lens out of focus manually) for each AF adjustment setting and hand-pick the best one before you compile the series and then determine which in the series yielded optimal focus.
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