EM1 Micro Focus Adjustment - Why and How to Perform

Phocal

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Yes, I am happy to have over interpreted, though I did just shoot a ballet performance with my 150,2 and not a single image was in focus except for the handful I took after switching to MF. Mixing up the MMF-3s would have been a good explanation and a relief. I hate focus tuning.
Focusing tuning can be a pain in the ass. Have you done the adjustment at all on the 150/2?

Next month I will be doing all my 4/3 lenses (4) and the 300/4 on two cameras in all combos with the TC’s. I will dedicate a day to doing them all, hopefully it doesn’t bleed over into a 2nd day (but I want to test a few things so it could take a bit longer). My plan is to assign each MMF-3 to a camera and only use that MMF-3 with that camera. While theoretically there should be no difference (I do plan to test one lens with both on the same camera to confirm), it will just put my mind at ease if I only use the MMF-3’s on the body tested on.
 

Speedliner

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Focusing tuning can be a pain in the ass. Have you done the adjustment at all on the 150/2?
Yes, I did all 5 one day including with the EC-14 and 20. Can’t bear doing it again.

I hate it enough that I’m considering keeping the 150,2 and selling the others to fund 40-150 and 300 Pros.
 

Mack

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Back to trying to do the 25 AF tuning points on the Olympus E-M1 Mark II.

I located a phase chart from a bench tech that fits close to the fine focus tuning grid on the Olympus E-M1 Mark II. Use it with a 2K monitor (1980x1020, etc.) and place it at whatever distance so that the outside AF viewfinder green target overlaps the center of the four outside center dots of the charts 25 targets. If the tuning is accurate in C-AF mode, you should see the pixels of the screen sharply when viewed at a 14x magnification. If off and image soft at 14x, try changing the AF Tuning by +/- 5 points an try again. It should appear grainy and pixelated if set right and not blurry. I also tried to do it on a fine 4K Eizo monitor's screen, but I could not see the pixelation of that screen so 2K screen was better for me.

I aligned the target's dark lines with the maximum grid lines set in the viewfinder that sets it up as being parallel to the screen and no tilt which results in keystoning of the lines. I could see the bow of the wide angle lens, but as long as they appear parallel it seemed to work well. The 12mm was close to my laptop's 17" diagonal screen (10" ??) and at around 56 inches to the front with the 12-100mm set at 85mm in my test. I just moved the single green AF target in the Super View Finder to another phase target and checked it there while checking all 25 of them with no need to move the camera or laptop.

I put the camera on a tripod and aligned the pattern full screen with normal exposure. I had the stabilization turned on too in both camera and lens following how I normally use it.

I did a random followup to double-check the pixelation of the phase chart and it seemed accurate on the second trial as well. I don't know if Olympus uses defocus zones in their lenses like Nikon and Sigma do and cause issues between normal lens testing gear we use (Lens Align or Reikan FoCal) and the real world, so I'd check the test outside too.

Got a shot of the rear of my camera's AF settings off the 12-200mm lens. The 100mm Tele settings are on top, and the 12mm Wide are the bottom numbers. The Tele +5 at the middle bottom is the odd one out, but it was consistent so some lens issue there perhaps.

Mack

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@Phocal
Dear Yoda, I ordered a test chart which finally arrived. I bought a real cheap version without software. I suffer a form of OCD but don't think it is the same as yours :).

I do have a question first up on a point which I might have missed in your article. I have a 40-150 Pro and a MC14. Have you found any difference whether the MC14 is attached or not? (I am guessing not because the converter is a fixed bit of optics, and that its physical manufacturing tolerance could be more easily controlled.)

Thanks and regards!
 

Phocal

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@Phocal
Dear Yoda, I ordered a test chart which finally arrived. I bought a real cheap version without software. I suffer a form of OCD but don't think it is the same as yours :).

I do have a question first up on a point which I might have missed in your article. I have a 40-150 Pro and a MC14. Have you found any difference whether the MC14 is attached or not? (I am guessing not because the converter is a fixed bit of optics, and that its physical manufacturing tolerance could be more easily controlled.)

Thanks and regards!
I haven’t done my 300/4 yet, so that means I have not done any testing with the MC14. But I don’t see how it would be any different than any other TC I have used or tested. I currently have 4 lenses that I have performed the micro focus adjustment on and every one of them needed more adjustment with the EC-14 and even more with the EC-20.

If I tested a lens and then tested it with TC and the setting needed didn’t change I would retest both of them. I have never sat down to figure out the math or physics as to why a TC needs more adjustment, but I can say that I have never seen a time where adding a TC didn’t require more adjustment.
 

Speedliner

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I’d guess that TCs need more adjustment for two reasons: 1) they add a joint which adds variance to the mix and 2) as multipliers they magnify variances in the original lens.

I can’t say with any certainty that 2 applies, I just don’t know, but 1 is a certainty. If you have multiple TCs you have to tune for each separately because they would have slightly different variances.
 

Bengeo

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I haven’t done my 300/4 yet, so that means I have not done any testing with the MC14.
Many thanks to Phocal for this thread. I had used Lens Align and FocusTune a while back for some Sony gear, but this thread prompted me to update it and test my 300mm f4 with the 1.4x converter.

I've been happy with the 300mm on its own, but with the converter it seemed to be front focused. I found using +5 with the converter gave the best test results and this is borne out by the photos now. The 300mm lens on its own showed it was fine with no adjustment. But there is a still problem. The Focus Adjustment is only applied in C-AF. That sort of makes sense as that is when PDAF only is used, but I've found that when using S-AF the photos are still front focused. I would like the option for the Focus Adjustment to be made in S-AF too.

I've also got the 40-150mm f2.8 so I guess I should test the converter with that now, but the photos have always seemed to be fine from that combination.
 

Phocal

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Many thanks to Phocal for this thread.
You are welcome, hope you found it useful.

But there is a still problem. The Focus Adjustment is only applied in C-AF. That sort of makes sense as that is when PDAF only is used, but I've found that when using S-AF the photos are still front focused. I would like the option for the Focus Adjustment to be made in S-AF too.
If it isn’t focusing correctly in SAF then you have problem. CDAF is basically 100% accurate.
 

DynaSport

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I just took my lunch break and visited a place nearby that I just discovered. I took some photos in CAF and some in SAF and I honestly don’t know which are which. Anyway, after getting back to the office and looking at them (on the camera screen, as I can’t load them on my work computer) I found tons of them were back focused. Over half I think. But the others came out very nice. I’m thinking it’s not a matter of back focusing as much as it is the focus area is too large and it focuses on something behind the bird, even though I am confident I had the focus box on the bird’s head. I think that because they were all misfocused. Some came out great. It’s a bit frustrating when you think you’ve got a great shot just to discover you have a great shot of some grass behind a duck.
 

panamike

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A big thank you for bringing this out into the open :2thumbs:

I was ready to return my week old EM1MK11 as i couldnt match my G80 BIF shots with it, any way today i took it out and used S-AF for some shots.

Up to know in C-AF this is the best i have had, i think its only this close to right because the birds are smaller in the frame and further away

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P5060120 by electric.mike, on Flickr

With S-AF and a bigger closer subject i got this, it looks some AF fine tune is in order before i use C-AF again.

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P5080110 by electric.mike, on Flickr
 

Phocal

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A big thank you for bringing this out into the open :2thumbs:

I was ready to return my week old EM1MK11 as i couldnt match my G80 BIF shots with it, any way today i took it out and used S-AF for some shots.

Up to know in C-AF this is the best i have had, i think its only this close to right because the birds are smaller in the frame and further away

View attachment 640426P5060120 by electric.mike, on Flickr

With S-AF and a bigger closer subject i got this, it looks some AF fine tune is in order before i use C-AF again.

View attachment 640427P5080110 by electric.mike, on Flickr
You are welcome, hope you get it all worked out.
 

barry13

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@Phocal - Hey Ronnie, thanks again for posting this how-to...

I finally got a ZD 50-200 SWD and realized I should do a focus calibration for it...

When I started testing the 50-200 SWD (in S-AF mode), I noticed it makes small focus adjustments back and forth as nears focus lock-in. This seemed odd as that is how CDAF works.

Regardless, today, I put the camera in C-AF mode, with BBF (hold to enable AF), and shot a test target and larger ruler with the ZD 50-200 SWD with and without both teleconverters, as well ZD 70-300 (no TCs).
There's definitely some missed-focus shots and some are clearly significantly front-focused and some are clearly significantly back-focused. As expected, in other words, and enough that any movements I could have made sitting and using a monopod could not explain them alone.

However, after that, I decided to do a quick comparison of my three telephotos, all at 200mm: 40-150Pro w MC-14, 50-200 SWD, and ZD 70-300. (the bare SWD was a bit better than the Pro+MC14, fwiw.)
I decided to do this one in S-AF, braced, as it would go faster not having to use BBF.
Well, none of the shots were obviously front or back-focused! (some have some shake but the ruler shows no focus problem)

So, I'm wondering if focus tuning makes any sense for those of us who use an E-M1 mk1 (and 4/3 lenses) with S-AF only?

I know you use C-AF a lot, so I know you need it, but do the rest of us?

I thought the consensus was that the E-M1 mk1 uses PDAF with non-CDAF optimized 4/3 lenses (and maybe all 4/3 lenses) in S-AF and C-AF, but now I'm not sure.

Thanks!


btw,
E-M1 mk1 firmware 4.4
50-200 SWD firmware 1.1
ZD 70-300 firmware 1.4
EC-14 & EC-20 firmware 1.1
 
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Ronnie,

Thanks again for doing this. It's incredibly helpful. I'm going through it with my µ4/3 telephotos.

I wanted to clarify the part of the process where I am taking each test shot, pulling focus between each shot. You mentioned that it is best to use the AF Focus Adjust screen to do the test, because this way you know you are using PDAF, and it simplifies the process (rather than going out, switching to C-AF, and then taking 5 shots). My problem is this: If I just take all five shots without trying to refocus every time, I can do it all without leaving the AF Focus Adjust screen. But I can't figure out how to change the focus from that screen, as there doesn't seem to be a movable target reticle (neither is there one on your sample image). Using the touchscreen doesn't do anything, and using the MF clutch pulls me out of the AF Focus Adjust screen entirely.

Did I miss something? How are you pulling focus off between each shot while staying in this mode? I can see how to do it the long way, but I wanted to know if there was a streamlined method. I hope my question makes sense, and thanks for your insight.
 

JDS

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One thing that confuses me about all this- why couldn't Olympus automatically do this internally, by comparing CDAF to PDAF? The camera would know where to place the lens focus position with CDAF, then could just look at where it places it with PDAF and have precise compensation numbers, couldn't it? Its kind of an irrelevant question since it doesn't have this feature, it just seems like it would be easy for them to implement. Do the entire process internally in a couple minutes...
 

barry13

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My problem is this: If I just take all five shots without trying to refocus every time, I can do it all without leaving the AF Focus Adjust screen. But I can't figure out how to change the focus from that screen, as there doesn't seem to be a movable target reticle (neither is there one on your sample image). Using the touchscreen doesn't do anything, and using the MF clutch pulls me out of the AF Focus Adjust screen entirely.
Hi,
1. the SWD lenses should be able to be focused as the focus ring always works
2. if you have the AF mode set to S-AF+M, the focus ring should work on the non-SWD lenses without using the clutch. I don't know if that'll kick you out of the Adjust screen as I didn't use that screen in my tests (yet).
 
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Hi,
1. the SWD lenses should be able to be focused as the focus ring always works
2. if you have the AF mode set to S-AF+M, the focus ring should work on the non-SWD lenses without using the clutch. I don't know if that'll kick you out of the Adjust screen as I didn't use that screen in my tests (yet).
Ill give that a shot. Thanks.
 

Phocal

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When I started testing the 50-200 SWD (in S-AF mode), I noticed it makes small focus adjustments back and forth as nears focus lock-in. This seemed odd as that is how CDAF works.
That is odd. I just tested this with my 50-200 and 150/2 and both seem to do something similar when having trouble focusing. But I don't believe it's using CDAF as my Canons would do that at times when having trouble focusing.

So, I'm wondering if focus tuning makes any sense for those of us who use an E-M1 mk1 (and 4/3 lenses) with S-AF only?
Yes. You are using PDAF and PDAF is not error free like CDAF (well it is almost error free, as close as us humans can get it). I actually use SAF more than CAF and I have noticed a big difference with my 150/2, especially when I am really close and have a super thin DOF.

Take this shot for example
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Curiosity by Phocal Art, on Flickr

A slight focus shift would make it unusable as the entire eye wouldn't be in focus and the DoF is basically the depth of the eye. Shot at 4.2 feet which gives about .2 inches DoF.

Personally, any camera I have ever owned that used PDAF I have calibrated the lenses. The amount of error with Olympus is much less than my Canon gear because you don't have the possibility of error due to miss alignment between the PDAF sensor and image sensor. But there still is that chance.
 

Phocal

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One thing that confuses me about all this- why couldn't Olympus automatically do this internally, by comparing CDAF to PDAF? The camera would know where to place the lens focus position with CDAF, then could just look at where it places it with PDAF and have precise compensation numbers, couldn't it? Its kind of an irrelevant question since it doesn't have this feature, it just seems like it would be easy for them to implement. Do the entire process internally in a couple minutes...
In theory is should work perfectly. Nikon is the only company to try it in the D500 (not sure if they implemented it in the D5) and I have heard mixed reviews about it.
 

Phocal

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Ronnie,

Thanks again for doing this. It's incredibly helpful. I'm going through it with my µ4/3 telephotos.

I wanted to clarify the part of the process where I am taking each test shot, pulling focus between each shot. You mentioned that it is best to use the AF Focus Adjust screen to do the test, because this way you know you are using PDAF, and it simplifies the process (rather than going out, switching to C-AF, and then taking 5 shots). My problem is this: If I just take all five shots without trying to refocus every time, I can do it all without leaving the AF Focus Adjust screen. But I can't figure out how to change the focus from that screen, as there doesn't seem to be a movable target reticle (neither is there one on your sample image). Using the touchscreen doesn't do anything, and using the MF clutch pulls me out of the AF Focus Adjust screen entirely.

Did I miss something? How are you pulling focus off between each shot while staying in this mode? I can see how to do it the long way, but I wanted to know if there was a streamlined method. I hope my question makes sense, and thanks for your insight.
To start off, I have not done my 300/4 yet, it's the only m4/3 lens I would do this for. I also don't recommend using CAF out of the testing menu because you could introduce error due to not having perfect CAF algorithms. The CAF algorithms are not the same as what they use for the PDAF system. Well they are, but with an added set of algorithms to predict movement. So I really do recommend using the testing menu at all times to force the camera into SAF with PDAF, something you can't do outside of it with a m4/3 lens.

I see what you mean about defocusing, tried it with my 300/4. Since I recommend staying within the testing menu and you can't manually defocus I would put my hand in front of the lens and hit the focus button. This should force it to try and get focus on your hand and defocus from the target. It is the only way I can see doing this with lenses that have the manual focus clutch which is a shame Olympus didn't fully think this one through.

Hope that helps
 
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