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Author Topic: Fuji Focus Bracketing  (Read 2172 times)

rdonson

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Re: Fuji Focus Bracketing
« Reply #20 on: August 27, 2018, 05:41:11 PM »

Re: BAB

You do have an "INTERVAL" that can be set between shots that you can set if you're concerned with shutter shock on the X-T2.  I've experimented on several occasions and noticed no vibration with the mechanical shutter.   Most of the time I just set the "INTERVAL" or 1 or 2 to be safe.  Other times I use the electronic shutter.  I am not using a macro lenses close up so that may be a factor.

A friend of mine who does use his 80mm macro up close on botanicals highly recommends using C-AF if there is any movement. 
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Ron

Chris Kern

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Re: Fuji Focus Bracketing
« Reply #21 on: November 05, 2018, 07:08:45 PM »

. . . has anybody figured out the semantics of the step value in the focus-bracketing menu, and how or whether it relates to the focal length of the lens or the distance between the lens and the subject?  The explanation in the manual . . . is not very useful.

I've been told to keep an eye out for an article on focus-bracketing that will be posted to the Fujjifilm X GFX website.  Hopefully it will include some information on how to estimate the optimal number of frames and step value for a particular subject based on the focal length, aperture, and subject distance—or some combination thereof.

The article I was told to watch for back in August finally has been published and it does indeed provide some useful information about the relationship between the step value and the subject, albeit expressed with respect to depth-of-field—i.e., a derived value—rather than focal length, aperture, and subject distance, which can be directly ascertained:

Quote
When using the Focus Bracketing feature on FUJIFILM cameras, users can set the Step value from 1 to 10. The Step is calculated using the distance between the near and far limit of the depth-of-field on the first image captured. Setting the Step to 1 moves the focus by approximately 20% of that distance. A Step of 5 moves the focus by around 100% of that distance. As an example, if the difference between the near and far limit of depth-of-field is four feet, a Step of 5 would move the focus point four feet for each shot.

Still, this a better than nothing and, with a little bit of effort, it should be possible to craft a software tool that would inform the user what step value and frame count were appropriate to keep the subject in focus.

Peter McLennan

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Re: Fuji Focus Bracketing
« Reply #22 on: November 06, 2018, 11:42:30 AM »

Congratulations to Fuji for being the first to implement this extremely useful function.  This should be available in all AF cameras.

I think the optimal solution from the photographer's point of view would be
  1) set start focus (manually)
  2) set end focus (manually)
  3) set number of frames
  3a) (optional) set time delay between frames
  4) go
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SrMi

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Re: Fuji Focus Bracketing
« Reply #23 on: November 07, 2018, 07:04:28 AM »

Congratulations to Fuji for being the first to implement this extremely useful function.  This should be available in all AF cameras.

<snip>

M43 cameras had focus bracketing for quite a while and D850 has it as well. Surprisingly, latest Sonys still don’t have that feature.
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TheDocAUS

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Re: Fuji Focus Bracketing
« Reply #24 on: November 08, 2018, 02:54:50 AM »

I am late to this discussion, but Micro 4/3 cameras have led the way with focus stacking, in camera. Fuji is playing catch up - which is great to see.

Panasonic and Olympus have been at it for a while, they use two different approaches. The Fuji approach seems much closer to what Olympus does. So videos on the Olympus focus stacking feature may assist the OP.

Panasonic cameras like the G9 and GH5 have two options for stacking. One is called Post Focus and the other is called Focus Bracketing. Focus Bracketing is similar to what Olympus and Fuji offer. But the Post Focus feature is so fast and powerful I have not used Focus Bracketing.

Post Focus is a two-stage process. After placing the camera in Post Focus mode and pressing the shutter release the camera finds all the focus points in the image and then takes a 6K video of all those focus points. The process takes about 2 seconds after pressing the shutter release. The lens must be in autofocus mode. You can create a focus stacked image in-camera using the G9’s touch screen or use a program like Helicon Focus. Helicon Focus imports the frames from the 6K video and you choose which frames to stack. You get a 18meg jpg in camera or a 50meg (approx.) TIF from Helicon Focus.

The challenges around the Fuji mostly concern DOF issues. A macro DOF calculator or a DOF Table may help. These types of discussions occur over at Helicon when using the Helicon FB Tube and also in the micro world, see here.

FF mirrorless cameras are far behind with only Nikon and Phase One offering choices, that I know about. Older Sony cameras can use a very basic focus stacking app (which you must buy) but it does not work with the current A9 or A7 series.

For the last 2 months I have been revising my infield focus stacking technique using Post Focus and working out how to best post process 6K videos. The journey is documented here.
« Last Edit: November 08, 2018, 03:17:21 AM by TheDocAUS »
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TheDocAUS

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Re: Fuji Focus Bracketing
« Reply #25 on: November 08, 2018, 03:45:56 AM »

There is another way which I have successfully used with a DSLR to work out how many shots to take for a stack. Set the lens to manual focus, turn on focus peaking in the camera and use Live view.

Now turn the focus ring on the lens back and forward so the focus moves across the subject, and watch the focus peak colour move across the subject and work out how many shots you need with an overlap in focus between the shots.

That whole process was manual, but you could go back and switch to the Fuji in-camera stacking mode and enter the number of shots (remember to switch the lens to AF). Over time I found I could work out the number of shots required simply by looking at the scene (mostly flowers and the like).
« Last Edit: November 08, 2018, 03:54:09 AM by TheDocAUS »
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Chris Kern

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Re: Fuji Focus Bracketing
« Reply #26 on: November 08, 2018, 05:06:01 PM »

I think the optimal solution from the photographer's point of view would be
  1) set start focus (manually)
  2) set end focus (manually)
  3) set number of frames
  3a) (optional) set time delay between frames
  4) go

Yes!  I think the specific procedure should be something along these lines:
  • Fix the location of the camera.
  • Manually set the desired aperture.
  • Manually use focus-peaking to enter a parameter representing the nearest part of the subject to appear in-focus.
  • Manually use focus-peaking to enter a parameter representing the farthest part of the subject to appear in-focus.
  • Manually enter a parameter representing the desired location of each successor frame's focus point (e.g., 25 percent of the computed depth-of-field behind the focus point of the current frame).
  • Optionally enter a parameter for the number of seconds to delay between frames.
  • Manually refocus on the nearest part of the subject.
  • Trigger the camera to dynamically compute the depth-of-field of each frame and automatically shoot the required number of frames until it reaches the farthest focus point.
This doesn't seem to me to be all that difficult for a firmware developer to implement.  Or am I missing something?

armand

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Re: Fuji Focus Bracketing
« Reply #27 on: November 08, 2018, 08:47:16 PM »

There is another way which I have successfully used with a DSLR to work out how many shots to take for a stack. Set the lens to manual focus, turn on focus peaking in the camera and use Live view.

Now turn the focus ring on the lens back and forward so the focus moves across the subject, and watch the focus peak colour move across the subject and work out how many shots you need with an overlap in focus between the shots.

That whole process was manual, but you could go back and switch to the Fuji in-camera stacking mode and enter the number of shots (remember to switch the lens to AF). Over time I found I could work out the number of shots required simply by looking at the scene (mostly flowers and the like).

Using the focus peaking in manual mode is the easiest way to get the fewest shots or have DOF only in the area that you want. I get the feeling though that the software does a better job at stitching if the steps are the same, didn't properly test it though and it's unlikely I'll have the drive to do it.
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