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Thread: GFX 50x, 100 manual focusing strategies

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    GFX 50x, 100 manual focusing strategies

    I've been working with MILCs for almost a decade -- longer, if you consider a Betterlight back on a Master Technika a MILC. During that time, I've developed a strategy to achieve rapid, accurate, and repeatable manual focus. In a nutshell, it's pretty simple:

    1. Use focus peaking
    2. Use magnification
    3. Use as much magnification as you can subject to the next line
    4. Use as low a peaking sensitivity as can produce visible peaking at the chosen magnification.
    5. The tie breaker: if you can’t see any peaking at maximum sensitivity at maximum magnification, back the magnification off a step and try again.


    The basics are easy to say. The subtleties can be difficult to understand. To try to make it easier for people to adopt this system, I've written a blog post that goes through the details and illustrates them with examples using a GFX 100.

    https://blog.kasson.com/gfx-100/opti...ng-strategies/

    Questions are welcome. I am particularly interested in hearing about things that I've said that are unclear, so that I can work on them.

    Thanks,

    Jim
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by JimKasson View Post
    I've been working with MILCs for almost a decade -- longer, if you consider a Betterlight back on a Master Technika a MILC. During that time, I've developed a strategy to achieve rapid, accurate, and repeatable manual focus. In a nutshell, it's pretty simple:

    1. Use focus peaking
    2. Use magnification
    3. Use as much magnification as you can subject to the next line
    4. Use as low a peaking sensitivity as can produce visible peaking at the chosen magnification.
    5. The tie breaker: if you can’t see any peaking at maximum sensitivity at maximum magnification, back the magnification off a step and try again.


    The basics are easy to say. The subtleties can be difficult to understand. To try to make it easier for people to adopt this system, I've written a blog post that goes through the details and illustrates them with examples using a GFX 100.

    https://blog.kasson.com/gfx-100/opti...ng-strategies/

    Questions are welcome. I am particularly interested in hearing about things that I've said that are unclear, so that I can work on them.

    Thanks,

    Jim
    The only MILC that I have ever used where I couldn't accurately manual focus the lens using Magnified Live View was the GFX 50S. For reasons I was not aware of, this was very poorly implemented in the 50S, despite the relatively high resolution of the EVF. I found myself guessing. Was that not changed in the GFX 100?

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by hcubell View Post
    The only MILC that I have ever used where I couldn't accurately manual focus the lens using Magnified Live View was the GFX 50S. For reasons I was not aware of, this was very poorly implemented in the 50S, despite the relatively high resolution of the EVF. I found myself guessing. Was that not changed in the GFX 100?
    Were you using the strategy that I described?

    As to the focusing in the GFX 100 as opposed to that of the GFX 50x, there have been changes to the finder and minor tweaks to the peaking controls. You get the best results with the GFX 50x the same way as you get the best results with the GFX 100, and that's the way I suggested in the OP. At least, that's been my experience, and I've tried a lot of MILCs.

    You should make sure you are focusing at or near taking aperture with some GFX lenses at some apertures, to calibrate out focus shift stemming from spherical aberration.

    Jim

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by JimKasson View Post
    Were you using the strategy that I described?

    Jim
    No, I returned the 50S to B&H and purchased an X1D. It was strange to me, because the EVF on the 50S had a higher resolution that the X1D. In practice, however, the magnified live view on the 50S was very grainy and it was difficult to discern the exact point at which you were in optimum focus. The difference between the two cameras on this score was readily apparent. Not a subtle difference. I would have thought that Fuji could correct it with a firmware update.

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by hcubell View Post
    No, I returned the 50S to B&H and purchased an X1D. It was strange to me, because the EVF on the 50S had a higher resolution that the X1D. In practice, however, the magnified live view on the 50S was very grainy and it was difficult to discern the exact point at which you were in optimum focus. The difference between the two cameras on this score was readily apparent. Not a subtle difference. I would have thought that Fuji could correct it with a firmware update.
    I've hardly ever focused the GFX 50x or the GFX 100 without focus peaking assistance. Why make it harder than it has to be? But I do remember from the 50S that focusing without peaking wasn't a particularly pleasant experience.

    Jim

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    Re: GFX 50x, 100 manual focusing strategies

    I have followed Jim's method for focusing the 50s and it works like a charm. I've trained myself enough to actually get 'almost' as accurate results by backing off slightly with magnification and no peaking vs peaking. But for dead on results Jim's methods are spot on.

    This is all due to the fact that the 50s and 100 have a slightly to very soft image at maximum magnification. Coming from a 3100 this was very different since at 100% pixels the 3100 was crystal clear and focus was extremely easy. The 4150 is a different animal and follows more Jim's methodology for the 50s/100 since it also is slightly soft. A little practice can result in your own workflow with a combination of all of the above.

    Victor
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by vjbelle View Post
    I have followed Jim's method for focusing the 50s and it works like a charm. I've trained myself enough to actually get 'almost' as accurate results by backing off slightly with magnification and no peaking vs peaking. But for dead on results Jim's methods are spot on.

    This is all due to the fact that the 50s and 100 have a slightly to very soft image at maximum magnification. Coming from a 3100 this was very different since at 100% pixels the 3100 was crystal clear and focus was extremely easy. The 4150 is a different animal and follows more Jim's methodology for the 50s/100 since it also is slightly soft. A little practice can result in your own workflow with a combination of all of the above.

    Victor
    Very strange. The GFX 100 has a state of the art EVF, so I don't understand why the Live view at 100% would be soft.
    If you use Focus Peaking to manually focus in Magnified Live view, isn't the Focus Peaking always on even when you are are not in Magnified Live View?

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    Re: GFX 50x, 100 manual focusing strategies

    Howard..... I don't recall if you ever owned a 3100 but a 100% view on that LCD was/is absolutely crystal clear - really remarkable. The 50s/r at 100% pixels is comparatively very soft and really requires peaking or some practice. When I had the GFX 100 I also saw that it was soft but not as bad as the 50s. It wasn't the EVF but rather the sensor feeding the information. My 4150 is also softer at 100% pixels than the 3100 and is much more similar to the GFX 100 although somewhat/slightly sharper. So, FMPOV peaking is a valuable assistant and I use it with my 4150 a lot and also with my 50s. Granted I can get focus really close and many times dead on without peaking however I have found that focus is always on with peaking.

    If peaking is activated it is always on regardless of view. It is a wonderful asset if the camera being used does not have focus stacking as focus can be easily and accurately moved forward manually by just following the peaking line while in non-magnified view.

    Victor

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    Re: GFX 50x, 100 manual focusing strategies

    I am so glad someone else finds the live view of the 4140 not to the same as previous phase backs. I have complained about this from day one.
    The 100 percent view is just not as crisp as the 3100 or IQ150/250/350.

    Can’t understand why it would be so different.

    Paul C

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    Re: GFX 50x, 100 manual focusing strategies

    Jim,
    I do have a few questions / clarifications. First, I’ve always second-guessed the terms being used. Fuji uses “sensitivity” (I guess; never tried one). P1 uses the term “threshold.” With P1, the higher the “threshold,” the less peaking there is. It sounds like from your blog that “sensitivity” means the opposite:
    “The photographer can vary that threshold with the sensitivity control. Higher sensitivity means a lower threshold, and more pixels flagged. Lower sensitivity means a higher threshold, and fewer pixels flagged.”

    So “sensitivity” is the inverse of “threshold.” That makes sense, but you can see how people might flip those meanings.

    Second, you mention “magnification” levels without context. If I remember correctly, the a7 series goes from full screen to "10x" to "100x." I don’t actually know what that means! 100x of what? Of full screen? So, if I have a 42mp a7rii, then I am looking at 1/100 of the image? Or does that mean 100%? On double tap, P1 goes to 100%. You can pinch out higher, up to 400%. That meaning is pretty clear; 4 screen pixels = 1 sensor pixel. Do you know how that compares with the GFX100 magnification options?

    I’ve been experimenting with zooming @ 400%, and I seem to err more often than not on front focusing. Not sure why that is; I will play / practice a bit more.

    This looks a bit front focused:


    This one looks better, but IMO had slightly less peaking:


    Dave
    Last edited by dchew; 4 Weeks Ago at 16:52.
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    Re: GFX 50x, 100 manual focusing strategies

    Practice helps.




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    Re: GFX 50x, 100 manual focusing strategies

    Looks good but maybe a hair front focused?

    John
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by jng View Post
    Looks good but maybe a hair front focused?

    John
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by dchew View Post
    I kept thinking the camera was going to give me a Moe Three Stooges Slap for shooting with the lens wide open.
    Hi,

    What camera did you use? With SLR kind cameras there is an issue of focus shift. You may focus with the lens fully open, but shoot with the lens stopped down. That will cause a systematic error, due to focus shift.

    With a view camera, focused at shooting aperture, that kind of systematic error would not occur.

    That said, with my manual focus tilt/shift systems I often focus at maximum aperture, because focusing feels more precise. But, accuracy may suffer.

    Best regards
    Erik

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by dchew View Post
    Jim,
    I do have a few questions / clarifications. First, I’ve always second-guessed the terms being used. Fuji uses “sensitivity” (I guess; never tried one). P1 uses the term “threshold.” With P1, the higher the “threshold,” the less peaking there is. It sounds like from your blog that “sensitivity” means the opposite:
    “The photographer can vary that threshold with the sensitivity control. Higher sensitivity means a lower threshold, and more pixels flagged. Lower sensitivity means a higher threshold, and fewer pixels flagged.”

    So “sensitivity” is the inverse of “threshold.”
    Apparently so; it seems that P1 and I are using the term "threshold" the same way.


    Quote Originally Posted by dchew View Post
    Second, you mention “magnification” levels without context. If I remember correctly, the a7 series goes from full screen to "10x" to "100x." I don’t actually know what that means! 100x of what? Of full screen? So, if I have a 42mp a7rii, then I am looking at 1/100 of the image? Or does that mean 100%? On double tap, P1 goes to 100%. You can pinch out higher, up to 400%. That meaning is pretty clear; 4 screen pixels = 1 sensor pixel. Do you know how that compares with the GFX100 magnification options?
    The highest magnification in the a7 series is a bit over 10 times (linearly). 10x would mean that you are looking at 1/100 of the image area. The highest magnification in the GFX 100 appears to be about the same.

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by ErikKaffehr View Post
    Hi,

    What camera did you use? With SLR kind cameras there is an issue of focus shift. You may focus with the lens fully open, but shoot with the lens stopped down. That will cause a systematic error, due to focus shift.
    Hi Erik,
    This was shot on the Alpa STC with my sk90 apo-digitar. It is the only lens I have right now with an aperture wider than f/5.6. I am playing around with this stuff just trying to learn the new boundaries of the IQ4 150, and what my best process is. Focus shift is one of the things I've been investigating. With the IQ3100, I used to just focus wide open @ f/5.6, stop down to f/11 and shoot; never worried about focus shift and rarely, if ever, saw the effects in images. That may or may not be the solution with this back, and especially with this lens.

    I do find it significantly easier to focus wide open, so I am trying to quantify any shift, not to mention shift vs. field curvature on each lens. It is a Pandora's box, but hopefully I will learn, refine a process and then not worry about it after that.

    We'll see!

    Dave
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by JimKasson View Post
    Were you using the strategy that I described?

    As to the focusing in the GFX 100 as opposed to that of the GFX 50x, there have been changes to the finder and minor tweaks to the peaking controls. You get the best results with the GFX 50x the same way as you get the best results with the GFX 100, and that's the way I suggested in the OP. At least, that's been my experience, and I've tried a lot of MILCs.

    You should make sure you are focusing at or near taking aperture with some GFX lenses at some apertures, to calibrate out focus shift stemming from spherical aberration.

    Jim

    Thanks Jim,

    Might I suggest a TLDR to abbreviate this, at least for GFX100 users?

    It is simply "set focus peaking to low, and use high magnification"?

    Fuji manual is not so useful, (the word 'magnification' yields 0 results!) but as I understand it:

    Set back focus S/C/M selector to M
    In Menu go to AF/MF, to 2/3 > 'MF ASSIST' > select Focus Peak > Red (low)
    When manually focusing, magnify by either turning lens focus (default option) which will zoom into AF area
    and/or magnify via a preset Fn button (I have set Fn3 for this)
    increase magnification zoom via rear command dial (in my setup)
    Focus for optimum peaking, ideally at shooting aperture,
    press-click rear command dial to return to full view
    take photograph.

    I likely missed something, please do correct me?
    Thanks. Your work on this is appreciated.

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by narikin View Post
    Thanks Jim,

    Might I suggest a TLDR to abbreviate this, at least for GFX100 users?

    It is simply "set focus peaking to low, and use high magnification"?

    Fuji manual is not so useful, (the word 'magnification' yields 0 results!) but as I understand it:

    Set back focus S/C/M selector to M
    In Menu go to AF/MF, to 2/3 > 'MF ASSIST' > select Focus Peak > Red (low)
    When manually focusing, magnify by either turning lens focus (default option) which will zoom into AF area
    and/or magnify via a preset Fn button (I have set Fn3 for this)
    increase magnification zoom via rear command dial (in my setup)
    Focus for optimum peaking, ideally at shooting aperture,
    press-click rear command dial to return to full view
    take photograph.

    I likely missed something, please do correct me?
    Thanks. Your work on this is appreciated.
    With respect to the basics, you've only missed one thing. With some subjects and some lenses, low peaking sensitivity won't light up *anything* at maximum magnification. Then you need to up the sensitivity. If that doesn't do it, you need to back down the magnification.



    Jim
    Last edited by JimKasson; 4 Weeks Ago at 11:46.

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by dchew View Post
    Hi Erik,
    This was shot on the Alpa STC with my sk90 apo-digitar. It is the only lens I have right now with an aperture wider than f/5.6. I am playing around with this stuff just trying to learn the new boundaries of the IQ4 150, and what my best process is. Focus shift is one of the things I've been investigating. With the IQ3100, I used to just focus wide open @ f/5.6, stop down to f/11 and shoot; never worried about focus shift and rarely, if ever, saw the effects in images. That may or may not be the solution with this back, and especially with this lens.

    I do find it significantly easier to focus wide open, so I am trying to quantify any shift, not to mention shift vs. field curvature on each lens. It is a Pandora's box, but hopefully I will learn, refine a process and then not worry about it after that.

    We'll see!

    Dave
    Hi Dave..... I've never checked for shifting with my LF lenses and after seeing these posts I did. All of my Schneider lenses (35,60,72,100,120,150,180) never move when stopping down with a Tapas lensAlign. If there is shifting it's easy to see shifting with peaking as the peaking will move as the lens is stopped down - as I know you know.

    The only lens I own that has shifting is the Rody 90. More than likely never enough to influence anything at my normal subject distances but to be really safe I will more than likely refocus at working aperture or focus exclusively at working aperture.

    Victor
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by vjbelle View Post
    Howard..... I don't recall if you ever owned a 3100 but a 100% view on that LCD was/is absolutely crystal clear - really remarkable. The 50s/r at 100% pixels is comparatively very soft and really requires peaking or some practice. When I had the GFX 100 I also saw that it was soft but not as bad as the 50s. It wasn't the EVF but rather the sensor feeding the information. My 4150 is also softer at 100% pixels than the 3100 and is much more similar to the GFX 100 although somewhat/slightly sharper. So, FMPOV peaking is a valuable assistant and I use it with my 4150 a lot and also with my 50s. Granted I can get focus really close and many times dead on without peaking however I have found that focus is always on with peaking.

    If peaking is activated it is always on regardless of view. It is a wonderful asset if the camera being used does not have focus stacking as focus can be easily and accurately moved forward manually by just following the peaking line while in non-magnified view.

    Victor
    Hi, Victor. I don't think it's the EVF or the sensor that's the problem. I think it's the firmware. The X1D Mark II uses the same EVF and the same sensor as the GFX 50S/R, but I expect the magnified Live View at 100% with Manual Focus should be the same as the X1D Mk I, which is crystal clear. Very easy to discern the exact point where the lens is in critical focus. I think someone (Paul?) mentioned that all of the Fuji cameras have this issue.
    I agree with you about focus peaking as a pretty cool way to manually set the lens for focus brackets. However, I don't like having the focus peaking on all of the time. It distracts me as I compose through the EVF. I think I may program one of the buttons to turn it on and off.

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    Re: GFX 50x, 100 manual focusing strategies

    I also find it very annoying to have focus peaking active all the time.

    IMO, Leica cameras have the best implementation: moving the focus ring automatically magnifies and focus peaking becomes active only when the image is magnified.

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by SrMphoto View Post
    I also find it very annoying to have focus peaking active all the time.
    It doesn't bother me much, but it would be nice to have a way to toggle peaking on and off. On the GFX 100, I have it in the Q menu, but it's a few clicks from "Off" to "PeakRL". Anybody know of a faster way?

    Jim

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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by JimKasson View Post
    It doesn't bother me much, but it would be nice to have a way to toggle peaking on and off. On the GFX 100, I have it in the Q menu, but it's a few clicks from "Off" to "PeakRL". Anybody know of a faster way?

    Jim
    For the GFX 50S, keep the rear dial pressed and hold until the focus peaking is active or inactive.

    Maybe it is synonymous with the GFX100.

    Greeting Gerd
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    Re: GFX 50x, 100 manual focusing strategies

    Quote Originally Posted by Gerd View Post
    For the GFX 50S, keep the rear dial pressed and hold until the focus peaking is active or inactive.

    Maybe it is synonymous with the GFX100.

    Greeting Gerd
    That works! Thankyouthankyouthankyou.
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