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Focus blending on new Fuji X T30

Discussion in 'Digital Image Editing & Printing' started by Terrywoodenpic, Jul 17, 2019.

  1. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    I wanted to test the focus bracket option on my new X T30. So I set up a few objects in my kitchen to cover a depth of eight inches not including the background.

    It is hard to find information on what the Fuji terms “Frames Step and Interval” actually mean. It turns out That frames is simply the chosen number of shots, Interval is the time between shots in seconds, with 0, being as fast as it can manage with the chosen shutter speed and file format.
    "Step" is more problematic as it relates to the “relative” focus step, and is not a fixed value. However, a value of 1 is equal to 20% of the Depth of field at the starting focus distance, with 5 equal to 100% which is why I decided to do a trial.

    My settings for the above scene were... Frames 50; step 1; interval 0. As I had no idea how many frames would be needed to cover 8 inches depth of field at step”1”
    The distance to the first object was 26" depth 8" camera settings 1/10 sec at F5.6, ISO 200 and 18-55 lens at 55mm

    It turned out that my first thought of 40 shots were not enough but 50 was. the first 24 were taken at full speed thereafter it slowed to about one a second as the buffer slowed ( The camera was set at normal power not boost)

    I could most likely have set the step value to 2 as there was very little change between individual steps at 1. But the cost of more shots is only in my time. And the better the overlap the smoother the result.

    I chose to shoot raw as this is my normal way of working, and although I had used a tripod, I did align the images in photoshop before focus blending them. no additional sharpening was applied.

    In the results are as below, and I have included 1st 20th and 50th shot as an indicator of the focus depth at those steps. Though viewed at 100% changes are of course more obvious.

    My next test will be the same, but including a wide depth of field landscape with a prominent foreground and distant detail.
    focus-blendweb.jpg
     
    Last edited: Jul 17, 2019
  2. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    The first twentieth and fiftieth shots.


    1web.jpg 20web.jpg 50web.jpg
     
  3. PeteRob

    PeteRob Well-Known Member

    That worked well but it seems a very large number of exposures to cover the distance.

    Edit: The 20th shot looks almost as good as the composite
     
  4. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    At this size that is true, but at larger sizes and at 100% there is an obvious difference.
    Looking at it again I found that Photoshop had made a couple of masking errors in the first orange. which I have manually corrected.
    I think changing the step to "two" would massively reduce the number of shots needed.

    It seems that we need to do trials to find what works best, as there is no way to predetermine the result, or the number of shots needed. The whole thing looks sharp at 100%

    As it is now blend-revised-web.jpg ,
     
  5. SqueamishOssifrage

    SqueamishOssifrage Well-Known Member

    Because I like the hackneyed 'pretty flowers in front, big mountains in back' type of thing, I wrote a program for my smartphone to create a stacking rack (so called after a 'rack' of slides). You can save your camera details (frame size, pixels etc) and then just enter lens focal length, aperture and closest point, and it gives you the minimum number of frames and the focus point for each.

    Surprisingly, it works rather well, but the macro version is simpler - it just sets the optimum step-size for the shot and can only be used on a focus rack.
     
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  6. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    I do not know why Fuji do not automate the step setting and number of shots, by letting you focus on the near and far point, if it is less than infinity.
    It already knows all the other necessary data
     
  7. daft_biker

    daft_biker Action Man!

    Interesting feature.

    Couple of degrees of tilt might have done the same job quicker though? Shift to keep the sensor vertically aligned with the subject would be a bonus.

    You youngsters and their technology;);):D.
     
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  8. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    This 84.5 year old youngster:confused: would point out that tilt, swing and shift only effect the "plane" of focus, not its extent.
    Focus blending increases it in depth in all planes.

    It allows you to use the aperture sweet spot for the lens, but extends that critical focus over the entire subject matter, with out introducing diffraction or compromising exposure through the use of small apertures...
    However the software used can introduce artifacts and faulty masking that may need to be dealt with. (as per my examples)

    Now that camera makers, like Fuji, have introduced focus bracket automation, the time taken to make the necessary exposures has been reduced to no more than a few seconds.
    and there are numerous software options to do the alignment and fusion, all at leisure, and in comfort of your home.

    It is also an "Interesting" and "useful" technique....that perhaps every photographer should have in their armoury, even if they use it only rarely.
    The fact that it can be done so quickly and in some cases handheld, and with no additional equipment, has now made focus fusion far more practical for day to day use.
     
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  9. PeteRob

    PeteRob Well-Known Member

    Andrew was commenting on this image and a bit of tilt would surely have done the trick.
     
  10. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    No it would not. A bit of swing would have helped. but it only swings the plane of focus depth of field is always at right angles to the plane of focus.
    few people, these days, actually understand what camera movements do to the geometry of an image and plane of focus. and how stopping down in these situations increases the depth at right angles to that plane, not down it.

    Tilt shift lenses are expensive and a poor substitute for the full set of movements on large format cameras.
    Focus fusion is not the same as, nor has the same effect as camera movements.
     
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  11. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    While I was out I took a hand held Focus bracket setting the camera to 6 shots, step of 5 and zero interval. it was very murky. exposure was 1/35 sec At F5.6 ISO 200 18mm on 18-55 lens.
    At that setting and focused on the yellow bush it reached infinity in three shots, so it only took three exposures out of the six set.
    At least I know it is doable now.
    This is the result. yellow-web.jpg
     
  12. daft_biker

    daft_biker Action Man!

    Aye..... 2 seconds at f/14 with tilt(or swing in large format speak) somewhere in the middle of the range and max shift to keep verticals vertical (or close enough:))....

    spice-tilt.jpg

    Without shift pointing the camera down would distort the subject by making the tops of the jars look bigger than the bottom and like they were leaning outwards, unless corrected with post processing.
     
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  13. cliveva

    cliveva Well-Known Member

    Hi, I was under the impression that focus stacking was primarily used for macro work, occasionally in landscape, in macro you would focus 1 or 2 mm at each shot, as depth of field is incredibly narrow with close focus.
    In landscape work it allows the use of the sweet spot of the lens, avoiding diffraction blurring from stopping down too much.
     
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  14. PeteRob

    PeteRob Well-Known Member

    Yes, you can use focus stacking for anything that doesn't move, but clearly for many macro applications it is the only way to achieve front-to-back sharpness. On a larger scale, using camera movements is the alternative, more limited, method. As pointed out, in small format tilt and shift lenses are expensive, though nothing like as dear as using a digital back on a large format camera. What struck me was, in this illustrative example, starting with 50 odd exposures to test the Fuji operation when the twentieth wasn't far out on its own seemed excessive and within the capability of a TSE lens as Andrew demonstrated. I have a 24 mm TSE not the 90 mm (or so) needed to reproduce it. Mirrorless small format cameras should make it much easier to use tilt/shift lenses depending on how they implement focus confirm. I look forward to seeing how the next generation of Canon perform.
     
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  15. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    The implementation of Fuji focus stacking sets the increment of focus movement to a fixed percentage of the depth of field of the first shot's distance measurement as focussed. That, as has been shown, produces high numbers of shots when it is set to "one" However it is still extremely quick.
    It is most likely quicker than accurately setting up a tilt shift lens. Which is again is rather quicker on a LF monorail.
    For processing stacked images one could choose to use either every shot, every other shot, or even every third shot, depending on how critical you wish to be.

    The advantage of a focus stack is that it is not confined to a single plane as is swing and tilt. Focus stacking covers the entire gamut of possible focus planes and points much like using a small aperture does, but without the diffraction, or the single plane of critical focus. As every shot is taken at the optimum aperture, every point is in critical focus if sufficient shots are taken. Which is probably why Fuji offer such a fine increment.

    As a photographer who used large format monorails most of my working life. I only wish I had had the option of focus fusion. It solves so many of the compromises that using camera movements presents to archetural and commercial photographers.
     
  16. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    That was probably true in the past. But now that the bracketing feature is inbuilt in the camera it has become quick and easy to use in other situations.
    It is now extremely useful in product and architectural photography. Especially when some parts of the image are close to the camera.
     
    Last edited: Jul 19, 2019
  17. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    I have had a further thought for landscape photographers who may want a critically sharp foreground and middle distance, but allow a more natural falloff of sharpness in the distance..
    All they need to do is take the bracket as usual, but leave out the last shots when fusing them.
    This would allow them to fine tune the effect. This would be difficult to achieve any other way.
     
  18. PeteRob

    PeteRob Well-Known Member

    Very likely - but there is some fun involved! I mostly use my TSE for keystoning correction as it was bought for photographing buildings rather than extending dof.

    I looked in my Fuji XH-1 manual but focus bracketing is not supported so it looks like an XT-3 specific feature - unless of course it has been added as a firmware update - must check.
     
  19. Terrywoodenpic

    Terrywoodenpic Well-Known Member


    It is on my X T30 so it seems to be only on the newer generation of X cameras, It is built in on the control dial as well as in the menu system, so probably not simply a firmware option. but will most likely feature on the next XH camera. Probably in an improved version. that is the way things seem to happen.

    If a tilt shift lens were to incorporate "fly by wire" auto focusing there would be no reason why you could not combine shift with focus bracketing, thereby controlling key-stoning and full sharpness. Where will it end? :)
     
    Last edited: Jul 19, 2019
  20. PeteRob

    PeteRob Well-Known Member

    I just looked - it is indeed a firmware update, and quite an old one. I must grit my teeth and apply them. I got bitten by my XE-2 when the firmware upgrade to 4 didn't work and it had to go back to Fuji. They fixed it for free but it made me nervous of doing it again.

    The XH-1 has a dedicated bracket selector - you configure whether it applies to exposure, white balance, iso, film profile and now presumably focus.

    Ha - an autofocus (or optimal focus) tilt/shift lens would be good! I presume that on a mirrorless camera the metering would also work when tilt or shift or both are applied. My main bugbear is a) remembering to put the metering on manual and b) remembering to pack a hand-held meter as inevitably the camera is all set up when I realise I didn't set the exposure before applying adjustments.
     
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