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09-05-2020, 08:21 AM   #1
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Concerns about focus adjustment on KP with SMC DA 18-135 WR

I went out shooting this morning and when I got home, I saw that the majority of my photos were really just not quite focused correctly. I've just upgraded to a KP from a Kr and figured maybe I still need to get used to some of the nuances of higher resolution, more (and faster) AF points, and new lenses I was working with. I decided to set up a little focus test on my desk, and I'm a concerned about the results. Camera was on a tripod, 135mm, ISO 800, 1/60, f 5.6. These are the 3 extremes using the build-in AF fine tuning (single lens). The +10 seems like the best of the 3, and I've never had to make more than a +- 1 or 2 adjustment before, and that was with an older MF lens.

Am I going crazy? Am I testing this wrong? I know my lighting could be better, but this seems quite extreme.

Thanks in advance for any guidance.

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Last edited by bobbyscon; 09-05-2020 at 08:30 AM.
09-05-2020, 08:30 AM   #2
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I also did a test with my SMC FA 50mm 1.4 all the way open at 1/320 and ISO 800. This test seems much more in line with what I would expect, which at least helps me understand it's very likely not the camera itself.
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09-05-2020, 09:18 AM   #3
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That's the fuzziest test shot I've ever seen. A properly done test should clearly show in and out of focus areas even if it needs adjustment. For focus adjustment the DOF should be in acceptable focus somewhere in the frame. My best guess would be someone smeared vaseline on your sensor based on what you've posted. Are you shooting at base ISO?

Are the lenses you are using sharp enough to resolve the detail from the distance you are shooting? The lack of contrast and clarity would suggest not. But lets say, 1/3 of your DoF should be infant of the 0 and 2//3s behind, Your plus 10 looks to be the best. On the 50 0 is the best. Each lens must be adjusted individually. Remember the focus adjustment moves the DoF forward and backwards, but it doesn't affect the quality of the image within the DoF.

I'd sart by contrasting those images. Contrast increases the appearance of sharpness. At least it would make it easier to see exactly what you're looking at.

Last edited by normhead; 09-05-2020 at 09:30 AM.
09-05-2020, 09:58 AM - 1 Like   #4
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QuoteOriginally posted by normhead Quote
That's the fuzziest test shot I've ever seen. A properly done test should clearly show in and out of focus areas even if it needs adjustment. For focus adjustment the DOF should be in acceptable focus somewhere in the frame. My best guess would be someone smeared vaseline on your sensor based on what you've posted. Are you shooting at base ISO?

Are the lenses you are using sharp enough to resolve the detail from the distance you are shooting? The lack of contrast and clarity would suggest not. But lets say, 1/3 of your DoF should be infant of the 0 and 2//3s behind, Your plus 10 looks to be the best. On the 50 0 is the best. Each lens must be adjusted individually. Remember the focus adjustment moves the DoF forward and backwards, but it doesn't affect the quality of the image within the DoF.

I'd sart by contrasting those images. Contrast increases the appearance of sharpness. At least it would make it easier to see exactly what you're looking at.
These are cropped at 100%, so I'd expect fuzziness, CA, and lack of IQ for the posted images. Having to go +10 on any lens (and I was making adjustments per lens) seems extreme. And the 18-135 being quite a common lens on these forums leads me to believe I certainly shouldn't expect to have to go that high. I was basing my judgments on what was in focus around the 0 mark looking for DOF on either side. I cropped to 100% to get a more defined scope of the DOF, but maybe that's my main mistake.

I will set up another round of tests with proper lighting and drop ISO to 200.

Thanks for the guidance!

09-05-2020, 10:30 AM   #5
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QuoteOriginally posted by bobbyscon Quote
I've never had to make more than a +- 1 or 2 adjustment before, and that was with an older MF lens.
I don't understand this comment. An MF (manual focus) lens isn't affected by an in-camera adjustment to the auto-focus system.

For AF lenses, you may want to try the 'Dot-Tune' method of focus calibration. Quick, easy, and doesn't require shooting any pictures.
09-05-2020, 10:44 AM - 1 Like   #6
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QuoteOriginally posted by Apet-Sure Quote
I don't understand this comment. An MF (manual focus) lens isn't affected by an in-camera adjustment to the auto-focus system.

For AF lenses, you may want to try the 'Dot-Tune' method of focus calibration. Quick, easy, and doesn't require shooting any pictures.
The problem I ran into with my Kr and an older lens was that the focus alert and dots were signaling in focus, but the shots weren't. Maybe it was a different setting to account for that and I've confused the different cameras.

I'll definitely check out that video, thanks!
09-05-2020, 11:05 AM - 1 Like   #7
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If anyone is confused it's more likely to be me! Come to think of it, when using manual focus lenses, I just trust the green hexagon to come on when it's supposed to. Maybe I need to do a comparison between viewfinder and LV focusing with MF lenses.

09-05-2020, 11:08 AM   #8
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If those are 100% crops you're too far away from the target I think. I do the fine tuning at about a meter distance for normalish lenses
09-05-2020, 11:21 AM   #9
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QuoteOriginally posted by Apet-Sure Quote
If anyone is confused it's more likely to be me! Come to think of it, when using manual focus lenses, I just trust the green hexagon to come on when it's supposed to. Maybe I need to do a comparison between viewfinder and LV focusing with MF lenses.
Isn't that what the DotTune video is all about? Get the lens to focus, switch to manual, then make sure the green dot stays solid and adjust the fine tuning until it does? It was actually incredibly helpful to take that video's approach and stop with the "take a photo, review, adjust, take a photo, review, adjust..."

Using this method, I was getting to a +7 or +8 for achieving the green dot, but still getting it at +10. Below +7 and I was no longer getting the indicator. It feels too high to be "normal", but it could be I've just never had to deal with it before.

QuoteOriginally posted by Serkevan Quote
If those are 100% crops you're too far away from the target I think. I do the fine tuning at about a meter distance for normalish lenses
That very well could be. The 18-135 does have a min focus distance that might be pushing back further that you might expect for this testing, though. I'm at about 2 - 2.5ft away (0.6 - 0.8 meters). I'm new to using these focus charts as well.
09-05-2020, 12:02 PM - 1 Like   #10
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QuoteOriginally posted by Apet-Sure Quote
I don't understand this comment. An MF (manual focus) lens isn't affected by an in-camera adjustment to the auto-focus system.
When doing a AutoFocus Fine Adjustment AF/FA manual lenses can be fine tuned if needed just like AF lenses....when using the AF confirmation (green hexagon) to focus your shots

The adjustment corrects for any manufacturing tolerance in either the lens or the camera (sensor) or both. All my AF lenses require +8 average, which indicates to me the issue is with the camera tolerances, not the lenses. Thankfully the AF/FA setting corrects them perfectly, which is the reason it was supplied as a menu item.

When adjusting manual lenses there is only one setting that can be used, the APPLY ALL setting. But because any problems with manual lenses can only be caused by the body, when using AF confirmation, this is not an issue.

---------- Post added 09-05-20 at 08:05 PM ----------

QuoteOriginally posted by bobbyscon Quote
These are cropped at 100%, so I'd expect fuzziness
Sorry but these are seriously wrong. Even at 100% crop you should have something in sharp focus.
09-05-2020, 12:13 PM   #11
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QuoteOriginally posted by pschlute Quote
The adjustment corrects for any manufacturing tolerance in either the lens or the camera (sensor) or both. All my AF lenses require +8 average, which indicates to me the issue is with the camera tolerances, not the lenses. Thankfully the AF/FA setting corrects them perfectly, which is the reason it was supplied as a menu item.
Ah, OK. This is what I was after. The fact that lenses may require going as "extreme" as a +8 is relatively normal makes me feel better. When looking at adjustments like these, having to go all the way to an end of the available adjustment range seems like a red flag. It sounds like the -10 to +10 range is actually a completely acceptable variance and one should only be worried if you find a need to go outside of that range.

Man I love this forum. Thank you all for the help!
09-05-2020, 12:19 PM - 1 Like   #12
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QuoteOriginally posted by bobbyscon Quote
having to go all the way to an end of the available adjustment range seems like a red flag. It sounds like the -10 to +10 range is actually a completely acceptable variance and one should only be worried if you find a need to go outside of that range.
I discovered this very early on with my K1 in 2016. Four years later the AF/FA set at the time still works. Any tolerance discrepancy does not change over time (at least over 4 years !)

The point about this adjustment is that it has always been necessary even going back to film camera days. But until the digital age and 36MP images we never noticed it. Most of us when using film never printed large enough for it to be an issue.
09-05-2020, 12:29 PM   #13
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QuoteOriginally posted by pschlute Quote
Sorry but these are seriously wrong. Even at 100% crop you should have something in sharp focus.
Well...crud. I had assumed that at 100% crop with these particular lenses (wide open, fully zoomed for the 18-135) that I shouldn't expect sharp without a bit of post. Unless we have a different definition of acceptability for sharp.

Here's samples with lighting and some post for contrast and levels (no sharpening). This was +8 AF adjusted, 1/160, f 5.6, ISO 400 at 135mm. I made sure my camera was level using the built-in sensors, but I think I was just a bit too elevated compared to the focus card. I was aiming for the center of the QR code.

---------- Post added 09-05-20 at 03:32 PM ----------

QuoteOriginally posted by pschlute Quote
But until the digital age and 36MP images we never noticed it. Most of us when using film never printed large enough for it to be an issue.
And I think that's part of my problem today. I went from the Kr to a KP (past few weeks) and I'm just starting to scrutinize the new camera and lenses. Over analyzing and not accounting for double the MP!

Thanks again
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09-05-2020, 12:34 PM - 1 Like   #14
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QuoteOriginally posted by bobbyscon Quote
I went from the Kr to a KP (past few weeks) and I'm just starting to scrutinize the new camera and lenses. Over analyzing and not accounting for double the MP!
Nothing wrong with zooming an image to check for nailing focus as long as you NEVER go over 100%


Here is a full size image (something I rarely post anywhere) , but it shows if you zoom to 100% what is in focus and what is not. The eyeball and the lower lid and everything on the same plane is in sharp focus.


Last edited by pschlute; 09-05-2020 at 12:40 PM.
09-05-2020, 01:13 PM   #15
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I hope you are using the camera set to center-only spot AF, and if on a tripod have the SR turned off. The lighting in your first test example is terrible. AF needs light!
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